## From NASA JPL-Caltech: “NASA’s WFIRST Will Help Uncover the Universe’s Fate”

From NASA JPL-Caltech

September 13, 2019

Calla Cofield
626-808-2469
calla.e.cofield@jpl.nasa.gov

Written by Ashley Balzer
NASA’s Goddard Space Flight Center, Greenbelt, Md.

NASA WFIRST depiction. Credit: NASA’s Goddard Space Flight Center

Scientists have discovered that a mysterious pressure dubbed “dark energy” makes up about 68% of the total energy content of the cosmos, but so far we don’t know much more about it.

Dark Energy Survey

Dark Energy Camera [DECam], built at FNAL

NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

Timeline of the Inflationary Universe WMAP

The Dark Energy Survey (DES) is an international, collaborative effort to map hundreds of millions of galaxies, detect thousands of supernovae, and find patterns of cosmic structure that will reveal the nature of the mysterious dark energy that is accelerating the expansion of our Universe. DES began searching the Southern skies on August 31, 2013.

According to Einstein’s theory of General Relativity, gravity should lead to a slowing of the cosmic expansion. Yet, in 1998, two teams of astronomers studying distant supernovae made the remarkable discovery that the expansion of the universe is speeding up. To explain cosmic acceleration, cosmologists are faced with two possibilities: either 70% of the universe exists in an exotic form, now called dark energy, that exhibits a gravitational force opposite to the attractive gravity of ordinary matter, or General Relativity must be replaced by a new theory of gravity on cosmic scales.

DES is designed to probe the origin of the accelerating universe and help uncover the nature of dark energy by measuring the 14-billion-year history of cosmic expansion with high precision. More than 400 scientists from over 25 institutions in the United States, Spain, the United Kingdom, Brazil, Germany, Switzerland, and Australia are working on the project. The collaboration built and is using an extremely sensitive 570-Megapixel digital camera, DECam, mounted on the Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory, high in the Chilean Andes, to carry out the project.

Over six years (2013-2019), the DES collaboration used 758 nights of observation to carry out a deep, wide-area survey to record information from 300 million galaxies that are billions of light-years from Earth. The survey imaged 5000 square degrees of the southern sky in five optical filters to obtain detailed information about each galaxy. A fraction of the survey time is used to observe smaller patches of sky roughly once a week to discover and study thousands of supernovae and other astrophysical transients.

Exploring the nature of dark energy is one of the primary reasons NASA is building the Wide Field Infrared Survey Telescope (WFIRST), a space telescope whose measurements will help illuminate the dark energy puzzle. With a better understanding of dark energy, we will have a better sense of the past and future evolution of the universe.

An Expanding Cosmos

Until the 20th century, most people believed that the universe was static, remaining essentially unchanged throughout eternity. When Einstein developed his general theory of relativity in 1915, describing how gravity acts across the fabric of space-time, he was puzzled to find that the theory indicated the cosmos must either expand or contract. He made changes to preserve a static universe, adding something he called the “cosmological constant,” even though there was no evidence it actually existed. This mysterious force was supposed to counteract gravity to hold everything in place.

However, as the 1920s were coming to a close, astronomer Georges Lemaitre, and then Edwin Hubble, made the startling discovery that with very few exceptions, galaxies are racing away from each other.

Edwin Hubble looking through a 100-inch Hooker telescope at Mount Wilson in Southern California, 1929 discovers the Universe is Expanding

The universe was far from static – it was ballooning outward. Consequently, if we imagine rewinding this expansion, there must have been a time when everything in the universe was almost impossibly hot and close together.

The End of the Universe: Fire or Ice?

The Big Bang theory describes the expansion and evolution of the universe from this initial superhot, superdense state. Scientists theorized that gravity would eventually slow and possibly even completely reverse this expansion. If the universe had enough matter in it, gravity would overcome the expansion, and the universe would collapse in a fiery “Big Crunch.”

If not, the expansion would never end – galaxies would grow farther and farther away until they pass the edge of the observable universe. Our distant descendants might have no knowledge of the existence of other galaxies since they would be too far away to be visible. Much of modern astronomy might one day be reduced to mere legend as the universe gradually fades to an icy black.

The Universe Isn’t Just Expanding – It’s Accelerating

Astronomers have measured the rate of expansion by using ground-based telescopes to study relatively nearby supernova explosions. The mystery escalated in 1998 when Hubble Space Telescope observations of more distant supernovae helped show that the universe actually expanded more slowly in the past than it does today.(?) The expansion of the universe is not slowing down due to gravity, as everyone thought. It’s speeding up.

Saul Perlmutter [The Supernova Cosmology Project] shared the 2006 Shaw Prize in Astronomy, the 2011 Nobel Prize in Physics, and the 2015 Breakthrough Prize in Fundamental Physics with Brian P. Schmidt and Adam Riess [The High-z Supernova Search Team] for providing evidence that the expansion of the universe is accelerating.

Fast forward to today. While we still don’t know what exactly is causing the acceleration, it has been given a name – dark energy. This mysterious pressure remained undiscovered for so long because it is so weak that gravity overpowers it on the scale of humans, planets and even the galaxy. It is present in the room with you as you read, within your very body, but gravity counteracts it so you don’t go flying out of your seat. It is only on an intergalactic scale that dark energy becomes noticeable, acting like a sort of weak opposition to gravity.

What Is Dark Energy?

What exactly is dark energy? More is unknown than known, but theorists are chasing down a couple of possible explanations. Cosmic acceleration could be caused by a new energy component, which would require some adjustments to Einstein’s theory of gravity – perhaps the cosmological constant, which Einstein called his biggest blunder, is real after all.

Alternatively, Einstein’s theory of gravity may break down on cosmological scales. If this is the case, the theory will need to be replaced with a new one that incorporates the cosmic acceleration we have observed. Theorists still don’t know what the correct explanation is, but WFIRST will help us find out.

WFIRST Will Illuminate Dark Energy

Previous missions have gathered some clues, but so far they haven’t yielded results that strongly favor one explanation over another. With the same resolution as Hubble’s cameras but a field of view that is 100 times larger, WFIRST will generate never-before-seen big pictures of the universe. The new mission will advance the exploration of the dark energy mystery in ways that other telescopes can’t by mapping how matter is structured and distributed throughout the cosmos, and also by measuring large numbers of distant supernovae. The results will indicate how dark energy acts across the universe, and whether and how it has changed over cosmic history.

The mission will use three survey methods to search for an explanation of dark energy. The High Latitude Spectroscopic Survey will measure accurate distances and positions of millions of galaxies using a “standard ruler” technique. Measuring how the distribution of galaxies varies with distance will give us a window into the evolution of dark energy over time. This study will connect the galaxies’ distances with the echoes of sound waves just after the Big Bang and will test Einstein’s theory of gravity over the age of the universe.

The High Latitude Imaging Survey will measure the shapes and distances of multitudes of galaxies and galaxy clusters. The immense gravity of massive objects warps space-time and causes more distant galaxies to appear distorted. Observing the degree of distortion allows scientists to infer the distribution of mass throughout the cosmos. This includes all of the matter we can see directly, like planets and stars, as well as dark matter – another dark cosmic mystery which is visible only through its gravitational effects on normal matter. This survey will provide an independent measurement of the growth of large-scale structure in the universe and how dark energy has affected the cosmos.

WFIRST will also conduct a survey of one type of exploding star, building on the observations that led to the discovery of accelerated expansion. Type Ia supernovae occur when a white dwarf star explodes. Type Ia supernovae generally have the same absolute brightness at their peak, making them so-called “standard candles.” That means astronomers can determine how far away they are by seeing how bright they look from Earth – and the farther they are, the dimmer they appear. Astronomers will also look at the particular wavelengths of light coming from the supernovae to find out how fast the dying stars are moving away from us. By combining distances with brightness measurements, scientists will see how dark energy has evolved over time, providing a cross-check with the two high-latitude surveys.

“The WFIRST mission is unique in combining these three methods. It will lead to a very robust and rich interpretation of the effects of dark energy and will allow us to make a definite statement about the nature of dark energy,” said Olivier Doré, a research scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, and leader of the team planning the first two survey methods with WFIRST.

Discovering how dark energy has affected the universe’s expansion in the past will shed some light on how it will influence the expansion in the future. If it continues to accelerate the universe’s expansion, we may be destined to experience a “Big Rip.” In this scenario, dark energy would eventually become dominant over the fundamental forces, causing everything that is currently bound together – galaxies, planets, people – to break apart. Exploring dark energy will allow us to investigate, and possibly even foresee, the universe’s fate.

Stem Education Coalition

Jet Propulsion Laboratory (JPL)) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge, on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

## From Science Alert: “Here Are NASA’s Wild Plans to Explore Time And Space For The Next 10 Years”

21 AUG 2019
MORGAN MCFALL-JOHNSEN

NASA hopes to reach a dead planet called Psyche. (NASA/JPL-Caltech/Arizona State Univ./Space Systems Loral/Peter Rubin)

NASA’s 10-year plan involves billions of dollars and spans millions of miles. And much like the universe, it’s only expanding.

Last year, the agency announced that it’s planning to send astronauts back to the Moon and eventually build a base there, with a Mars-bound mission to follow in the years after that.

In June, the agency introduced a mission that aims to fly a nuclear-powered helicopter over the surface of Titan, an icy Moon of Saturn’s, to scan for alien life. NASA wants to looking for life in other places too, like the ocean below the icy surface of Jupiter’s Moon Europa.

Other future missions will try to photograph our entire cosmic history and map the dark matter and dark energy that govern our Universe.

Here are some of NASA’s biggest and most ambitious plans for the coming decade.
1. Several ground-breaking NASA missions are already in progress, including the Parker Solar Probe, which will will rocket past the Sun a total of 24 times.

NASA Parker Solar Probe Plus named to honor Pioneering Physicist Eugene Parker

Launched: August 12, 2018

Arrived: November 5, 2018

The probe is travelling closer to the Sun than anything from Earth before it. The mission aims to investigate the forces behind solar wind, which could inform efforts to protect technology on Earth from the Sun’s flare-ups.

Parker slingshots around the Sun at record speeds of up to 213,200 mph (343,000 km/h); it’s currently approaching its third close encounter. A powerful heat shield keeps the spacecraft’s equipment cool.

The Parker Solar Probe will get closer to the sun than any other probe before it. (NASA Goddard/Youtube)

2. Far from the Sun, New Horizons is exploring the Kuiper Belt, a region of millions of chunks of ice left over from the Solar System’s birth.

NASA/New Horizons spacecraft

Kuiper Belt. Minor Planet Center

Launched: January 19, 2006

Arrived at Ultima Thule: January 1, 2019

The New Horizons spacecraft visited Pluto and the ice dwarfs surrounding it in 2015. In January, the spacecraft reached the farthest object anything human-made has ever visited: a snowman-shaped space rock called 2014 MU69 (or Ultima Thule).

It sent back the following video of Ultima Thule, though it will likely take until late 2020 for scientists to receive and download all the data from New Horizons’ flyby.

So far, we’ve learned that the primordial object contains methanol, water ice, and organic molecules.

3. On the surface of Mars, the InSight lander is listening for quakes.

NASA/Mars InSight Lander

Launched: May 5, 2018

Arrived: November 26, 2018

Since the InSight lander touched down on the surface of the red planet, it has detected dozens of Mars quakes. The early data is giving scientists new insight into the planet’s internal structure.

Illustration of the InSight lander on Mars. (NASA/JPL-CaltechAn)

4. A new Mars rover will join InSight next year. NASA is currently building the vehicle in its Jet Propulsion Laboratory in Pasadena, California.

NASA Mars 2020 rover schematic

NASA Mars 2020 Rover

Members of NASA’s Mars 2020 project after attaching the rover’s mast. (NASA/JPL-Caltech)

5. Researchers hope a future mission to Mars could return the Martian rock samples that the Mars 2020 rover collects back to Earth.

Planned launch: Unknown

Anticipated arrival: Unknown

Until NASA sends another robot to Mars that could launch the stored samples to Earth, the 2020 rover will store the samples in its belly and search for a place on Mars where it can stash them for pickup.

Proposed Mars Sample Return mission launching samples towards Earth. (NASA/JPL-Caltech)

Planned launch: July 2020

Anticipated arrival: February 2021

The Mars 2020 rover will search for signs of ancient microbial alien life on the red planet, collect and stash rock samples, and test out technology that could pave the way for humans to walk the Martian surface one day.

You can tune in to NASA’s live broadcast of the Mars 2020 rover’s construction anytime to watch the US$2.1 billion mission take shape. 6. NASA eventually hopes to send a crewed mission to Mars. But before that, the agency plans to return astronauts to the Moon and built a lunar base there. Planned launch: Unknown Anticipated arrival: 2024 NASA wants to send humans to the Moon again by 2024. Those would be the first boots on the lunar surface since the Apollo program ended over 45 years ago. This time, however, NASA wants to build a Moon-orbiting space station with a reusable lunar-landing system. The idea is that the lunar base could allow for more in-depth scientific research of the Moon, and potentially even enable us to mine resources there that could be converted to fuel for further space travel. 7. From the lunar surface, astronauts may springboard to Mars. Planned launch: 2030s Anticipated arrival: 2030s The next Moon mission will test deep-space exploration systems that NASA hopes will carry humans on to Mars. Astronauts travelling to Mars would have to spend about three years away from Earth. In order to explore of the red planet, human travellers would have to be able to use the materials available on the lunar and Martian surfaces. NASA is already designing future astronauts’ gear. They’re sending spacesuit material on the Mars 2020 rover to test how it holds up in the planet’s harsh atmosphere. A deep-space habitat competition this year yielded a 3D-printable pod that could be constructed using materials found on Mars. Concept illustration of Martian habitats. (JPL/NASA) 8. NASA also plans to investigate our Solar System’s past by launching a mission to an asteroid belt surrounding Jupiter. Planned launch: October 2021 Anticipated arrival: 2027 A mysterious swarm of Trojan asteroids – the term for space rocks that follow planets – trail Jupiter’s orbit around the Sun. NASA’s Lucy mission plans to visit six of them. “We know very little about these objects,” Jim Green, the leader of NASA’s planetary science program, said in a NASA video. “They may be captured asteroids, comets, or even Kuiper Belt objects.” What we do know is that the objects are as old as the Sun, so they can serve as a kind of fossil record of the Solar System. 9. Relatively nearby, a spacecraft will scan for alien life in the saltwater ocean on Jupiter’s Moon Europa. Planned launch: 2020s Anticipated arrival: Unknown When Galileo Galilei first looked at Jupiter through his homemade telescope in 1610, he spotted four Moons circling the planet. Nearly 400 years later, NASA’s Galileo mission found evidence that one of those Moons, Europa, conceals a vast ocean of liquid water beneath its icy crust. NASA is planning to visit that ocean with the Europa Clipper, a spacecraft that will fly by the Moon 45 times, getting as close at 16 miles above the Moon’s surface. NASA/Europa Clipper annotated Clipper will fly through water vapour plumes that shoot out from Europa’s surface (as seen in the NASA visual above) to analyse what might be in the ocean. Radar tools will also measure the thickness of the ice and scan for subsurface water. 10. That investigation could help scientists prepare to land a future spacecraft on Europa’s surface and punch through the ice. NASA’s Lucy mission visiting asteroids near Jupiter. (Southwest Research Institute) Anticipated launch and arrival: Unknown The future lander would search for signs of life in the ocean, digging 4 inches below the surface to extract samples for analysis in a mini, on-the-go laboratory. 11. A nuclear-powered helicopter called Dragonfly will take the search for alien life one planet further, to Saturn’s largest Moon, Titan. Dragonfly visiting sampling location on Titan. (NASA) Planned launch: 2026 Anticipated arrival: 2034 Titan is a world with ice, liquid methane pools, and a thick nitrogen atmosphere. It somewhat resembles early Earth, since it has carbon-rich organic materials like methane and ethane. Scientists suspect that an ocean of liquid water might lurk 60 miles below the ice. All that makes Titan a contender for alien life. But getting to the distant, cold Moon is not easy – Saturn only gets about 1 percent of the sunlight that bathes Earth, so a spacecraft can’t rely on solar energy. Instead, Dragonfly will propel itself using the heat of decaying plutonium. 12. Another NASA team is developing a spacecraft to probe the metal core of a dead planet called Psyche. Planned launch: 2022 Anticipated arrival: 2026 Most of the asteroids in our Solar System are made of rock or ice, but Psyche is composed of iron and nickel. That’s similar to the makeup of Earth’s core, so scientists think Psyche could be a remnant of an early planet that was decimated by violent collisions billions of years ago. NASA is sending a probe to find out. “This is an opportunity to explore a new type of world – not one of rock or ice, but of metal,” Linda Elkins-Tanton, who’s leading the mission, said in a press release. “This is the only way humans will ever visit a core.” If Psyche really is the exposed core of a dead planet, it could reveal clues about the Solar System’s early years. The probe NASA plans to send to Psyche would be the first spacecraft to use light, rather than radio waves, to transmit information back to Earth. The agency gave the team the green light to start the final design and early assembly process in June. 13. NASA also has 176 missions in the works that use CubeSats: 4-by-4-inch cube-shaped nanotechnology satellites. Three CubeSats ejected from the Japan Aerospace Exploration Agency’s Kibo laboratory. (NASA) NASA is partnering with 93 organisations across the US on these CubeSat projects. Such satellites have already been built and sent to space by an elementary school, a high school, and the Salish Kootenai College of the Flathead Reservation in Montana. The first CubeSats sent to deep space trailed behind the InSight Mars lander last year. They successfully sent data from the InSight lander back to Earth as it landed on the Martian surface. One planned mission using the nanotechnology will use lasers to search for ice on the Moon’s shadowy south pole. It’s expected to launch in November 2020. Another CubeSat mission, also set to launch in 2020, will fly past an asteroid near Earth and send back data. It will be the first exploration of an asteroid less than 100 meters in diameter. That data will help scientists plan for future human missions to asteroids, where astronauts might mine resources as they explore deep space. 14. Closer to home, the European Space Agency’s Euclid telescope will study dark matter and dark energy. ESA/Euclid spacecraft Planned launch and arrival: 2022 Dark matter makes up 85 percent of the universe, but nobody is sure what it is. Part of the problem is that we can’t see it because it doesn’t interact with light. Dark matter’s gravity holds the entire universe together, while an unknown force called dark energy pushes everything apart. Dark energy is winning, and that’s why the universe is expanding. As Euclid orbits Earth, the space telescope will measure the universe’s expansion and attempt to map the mysterious geometry of dark matter and energy. NASA is working with the ESA on imaging and infrared equipment for the telescope. 15. The James Webb Space Telescope, which has a massive, 18-panel mirror, will scan the universe for life-hosting planets and attempt to look back in time to photograph the Big Bang. NASA/ESA/CSA Webb Telescope annotated Planned launch and arrival: 2021 It’s been almost 30 years since the Hubble Space Telescope launched. The James Webb Space Telescope is its planned replacement, and it packs new infrared technology to detect light beyond what the human eye can see. The telescope’s goal is to study every phase of the universe’s history in order to learn about how the first stars and galaxies formed, how planets are born, and where there might be life in the universe. A 21-foot-wide folding beryllium mirror will help the telescope observe faraway galaxies in detail. A five-layer, tennis court-size shield protects it from the Sun’s heat and blocks sunlight that could interfere with the images. 16. The James Webb Space Telescope will be capable of capturing extremely faint signals. The farther it looks out into space, the more it will look back in time, so the telescope could even detect the first glows of the Big Bang. The telescope will also observe distant, young galaxies in detail we’ve never seen before. The expanding universe. (NASA) 17. The Wide Field InfraRed Survey Telescope (WFIRST) is expected to detect thousands of new planets and test theories of general relativity and dark energy. NASA/WFIRST Planned launch and arrival: mid-2020s WFIRST’s field of view will be 100 times greater than Hubble’s. Over its five-year lifetime, the space telescope will measure light from a billion galaxies and survey the inner Milky Way with the hope of finding about 2,600 exoplanets. See the full article here . Please help promote STEM in your local schools. Stem Education Coalition • #### richardmitnick 1:02 pm on July 4, 2019 Permalink | Reply Tags: Astronomy ( 8,814 ), Astrophysics ( 5,941 ), Basic Research ( 12,030 ), Cosmology ( 6,131 ), NASA WFIRST, STScI ( 5 ) ## From Space Science Telescope Institute: “STScI to Design Science Operations for New Panoramic Space Telescope” From Space Science Telescope Institute NASA/WFIRST STScI is thrilled to be able to help NASA, the science teams, and the astronomical community, in making WFIRST a success. NASA has awarded a contract to the Space Telescope Science Institute (STScI) in Baltimore, Maryland, for the Science Operations Center (SOC) of the Wide Field Infrared Survey Telescope (WFIRST) mission. WFIRST is a NASA observatory designed to settle essential questions in a wide-range of science areas, including dark energy and dark matter, and planets outside our solar system. July 02, 2019 Ray Villard Space Telescope Science Institute, Baltimore, Maryland 410-338-4514 villard@stsci.edu Roeland van der Marel Space Telescope Science Institute, Baltimore, Maryland 410-338-4931 marel@stsci.edu NASA has awarded a contract to the Space Telescope Science Institute (STScI) in Baltimore, Maryland, for the Science Operations Center (SOC) of the Wide Field Infrared Survey Telescope (WFIRST) mission. WFIRST is a NASA observatory designed to settle essential questions in a wide-range of science areas, including dark energy and dark matter, and planets outside our solar system. WFIRST was ranked as the highest scientific priority for a large space astrophysics mission in the Decadal Survey conducted by the National Research Council in 2010. The launch of WFIRST is planned for the mid-2020s. To be located one million miles beyond Earth, WFIRST’s prime mission will last for five years. The approximately$34.6 million cost-plus-fixed-fee contract was issued as a sole-source procurement. The SOC leads work on the mission’s observation scheduling system, wide field instrument data processing system for the direct-imaging mode, and the mission’s entire data archive. STScI has already performed pre-formulation, formulation, and design activities for the WFIRST mission since 2014. The contract enables continued science operations system engineering, design, science research support, and scientific community engagement and public outreach through September 2021.

STScI is the science operations center for both the Hubble and upcoming James Webb Space Telescope. Its expertise with these great observatories puts the Institute in a unique position to support cutting-edge astronomical research well into the future. STScI was established in 1981 on the Johns Hopkins University campus, and is operated by the Association of Universities for Research in Astronomy (AURA).

AURA/STScI will join a team led by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, which manages the WFIRST mission for NASA. The team also includes the Jet Propulsion Laboratory (JPL) in Pasadena, California; the Infrared Processing and Analysis Center (IPAC), also in Pasadena; a science team comprised of members from U.S. research institutions across the country, including STScI astronomers; and various industrial and international partners.

The WFIRST observatory will follow on the legacy of the Hubble Space Telescope. WFIRST has the same-sized mirror, but will have a wide-field view of the universe in near-infrared light. Sharp exposures of millions of far-flung galaxies will be done in a fraction of the time that it would take with Hubble. WFIRST’s deep-space view will cover 100 times the area of sky as Hubble.

“I am looking forward to the scientific power that WFIRST will provide to the entire astrophysics community. The data sets will be large, accessible to all, and open to support exploration of multiple facets of the universe,” said STScI Deputy Director Nancy Levenson.

Science research with WFIRST will work in synergy with and complement Webb and extraordinarily powerful new ground-based telescopes going into operation in the 2020 decade. This promises to open a remarkable new era of astrophysics.

“The WFIRST mission promises to discover thousands of extrasolar planets, survey millions of galaxies, and image billions of individual stars. The research collectively will encompass galactic and stellar populations, environments, evolution, and demographics across all of astrophysics,” said STScI WFIRST Mission Scientist Karoline Gilbert. “Interesting objects discovered by WFIRST can later be studied in more detail by the Webb telescope.”

In addition to having a wide-field camera, WFIRST will have a coronagraph to block out the glare from a star to look for accompanying planets. This technology demonstrator is expected to find exoplanets, and also pave the way for many of the large space-based missions being studied for the 2030s and beyond, that will directly image Earth-like exoplanets. WFIRST promises to advance the search for worlds that might support life, as we know it.

“The Barbara A. Mikulski Archive for Space Telescopes (MAST)
at STScI already holds the astronomical data from some 20 astronomy missions. The addition of the WFIRST data, including new cloud-based products to support data analysis, will add considerably to its scientific discovery potential for present and future generations of astronomers,” said Arfon Smith, the STScI Data Science Mission Head.

WFIRST will begin operations after traveling to a gravitational balance point known as Earth-Sun L2, which is located about one million miles from Earth in a direction directly opposite the Sun.

“WFIRST will offer the world’s astronomers a unique mixture of new capabilities for large surveys, pointed guest-observer science, and archival research. STScI will leverage its expertise in these areas from Hubble, Webb, and other missions. We are thrilled to be able to help NASA, the science teams, and the astronomical community, in making WFIRST a success. The discoveries will be unprecedented,” said Roeland van der Marel, the STScI WFIRST Mission Head.

five-ways-keep-your-child-safe-school-shootings

We are the Space Telescope Science Institute in Baltimore, Maryland, operated by the Association of Universities for Research in Astronomy. We help humanity explore the universe with advanced space telescopes and ever-growing data archives.

Founded in 1982, we have helped guide the most famous observatory in history, the Hubble Space Telescope.

NASA/ESA Hubble Telescope

Since its launch in 1990, we have performed the science operations for Hubble. We also lead the science and mission operations for the James Webb Space Telescope (JWST), scheduled for launch in 2019.

NASA/ESA/CSA Webb Telescope annotated

We will perform parts of the science operations for the Wide Field Infrared Survey Telescope (WFIRST), in formulation for launch in the mid-2020s, and we are partners on several other NASA missions.

NASA/WFIRST

Our staff conducts world-class scientific research; our Barbara A. Mikulski Archive for Space Telescopes (MAST) curates and disseminates data from over 20 astronomical missions;

Mikulski Archive For Space Telescopes

and we bring science to the world through internationally recognized news, education, and public outreach programs. We value our diverse workforce and civility in the workplace, and seek to be an example for others to follow.

## From NYT: “Astronomers’ Dark Energy Hopes Fade to Gray”

The New York Times

FEB. 19, 2018
Dennis Overbye

A remnant from a Type 1A supernova observed in the Milky Way, one of the cosmic markers of how fast the universe is expanding. Observing exploding stars helped astronomers first discover the existence of dark energy nearly 20 years ago. Credit Chandra X-ray Observatory/NASA

NASA/Chandra Telescope

A star-crossed mission nearly 20 years in the making that was intended to seek an answer to the most burning, baffling question in astronomy — and perhaps elucidate the fate of the universe — is in danger of being canceled.

The Wide-Field Infrared Survey Telescope, or WFIRST, was being designed to investigate the mysterious force dubbed dark energy that is speeding up the expansion of the universe and search out planets around other stars.

NASA/WFIRST

In 2010, a blue-ribbon panel from the National Academy of Sciences charged with charting the future of space-based astronomy gave the mission the highest priority for the next decade. Under the plan, it could have launched in mid-2020s with a price tag of $3.2 billion.american But it was zeroed out in the NASA budget proposed by President Trump last week. In a statement accompanying the budget, Robert M. Lightfoot Jr., the agency’s acting administrator, called the deletion “one hard decision,” citing the need to divert resources to “other agency priorities.” NASA is shifting its focus back to the moon. Nobody is under any illusion that a president’s budget proposal is the last word on anything. Congress, which usually listens to the academy’s recommendations, will have the last word in a dance that many NASA missions, including the Hubble Space Telescope, have participated in. As the old saying among space scientists at the Jet Propulsion Laboratory, home of many missions, goes: “It’s not a real mission until it is canceled.” Robert Lightfoot Jr., the acting administrator of NASA, giving a state of the agency speech on Feb. 12 at the Marshall Space Flight Center in Huntsville, Ala. Credit Bill Ingalls/(NASA, via Associated Press The proposed cancellation drew an outcry from astronomers, who warned that stepping back from the mission would be stepping back from the kind of science that made America great and would endanger future projects that, like this one, require international help. It drew comparisons to the cancellation of the Superconducting Supercollider that ended American supremacy in particle physics. Superconducting Super Collider map, in the vicinity of Waxahachie, Texas. __________________________________________________________________________ American astronomical Society Contacts: Rick Fienberg AAS Press Officer +1 202-328-2010 x116 Joel Parriott AAS Deputy Executive Officer & Director of Public Policy +1 202-328-2010 x120 Sharing alarm voiced by other scientists, leaders of the American Astronomical Society (AAS) are expressing grave concern over the administration’s proposed cuts to NASA’s astrophysics budget and the abrupt cancellation of the Wide Field Infrared Survey Telescope (WFIRST). “We cannot accept termination of WFIRST, which was the highest-priority space-astronomy mission in the most recent decadal survey,” says AAS President-Elect Megan Donahue (Michigan State University). “And the proposed 10% reduction in NASA’s astrophysics budget, amounting to nearly$1 billion over the next five years, will cripple US astronomy.”

WFIRST, the successor to the 28-year-old Hubble Space Telescope and the forthcoming James Webb Space Telescope, is the top-ranked large space-astronomy mission of New Worlds, New Horizons in Astronomy and Astrophysics, the National Academies’ Astro2010 decadal survey, and is an essential component of a balanced space astrophysics portfolio. Cutting NASA’s astrophysics budget and canceling WFIRST would leave our nation without a large space telescope to succeed Hubble and Webb. Yet just last year another National Academies report, Powering Science: NASA’s Large Strategic Missions, found that “large strategic missions are critical for balance and form the backbone of the disciplines” of NASA’s Science Mission Directorate (SMD), which includes astrophysics. The same report further recommended that “NASA should continue to plan for large strategic missions as a primary component for all science disciplines as part of a balanced program that also includes smaller missions.”

“The AAS has long supported community-based priority setting as a fundamental component in the effective funding, management, and oversight of the federal research enterprise,” says AAS Executive Officer Kevin B. Marvel. “This process has been tremendously successful and has led to US preeminence in space science through missions that are now household names, like Hubble.” Marvel continues, “Not only is WFIRST a top decadal-survey priority in astronomy and astrophysics, but the mission has also undergone rigorous community, agency, and Congressional assessment and oversight and meets the high expectations of an astrophysics flagship.”

Indeed, after Astro2010, scientific and technological advancements enabled an enhanced WFIRST that would be 100 times more powerful than Hubble. Follow-on National Academies’ reports in 2013 and 2016 reaffirmed the significant scientific merit of the enhanced WFIRST mission, and their recommendations for careful monitoring of potential cost and schedule drivers led to NASA’s commissioning of the WFIRST Independent External Technical / Management / Budget Review (WIETR) last fall.

Neither the commissioning of the WIETR nor the content of its findings are an indication that WFIRST is experiencing or will experience the cost overruns that the Webb telescope experienced. In fact, the opposite is true. As Thomas Young, former director of NASA’s Goddard Space Flight Center and former president and chief operating officer of Martin Marietta Corp., testified to the House Science Subcommittee on Space in December 2017, that WFIRST has undergone extensive scrutiny is “no cause for panic. What is transpiring is a perfectly healthy process to assure that the scope, cost, and risk are appropriately defined.”

NASA’s SMD Associate Administrator, Thomas Zurbuchen, fully agreed with the WIETR recommendations to match mission cost with appropriate resources as part of a balanced astrophysics portfolio. After undergoing a redesign over the last several months, WFIRST would once again fit both within the February 2016 budget approved by NASA at the onset of its mission formulation phase and within the notional five-year budget profile the administration requested for NASA astrophysics in its FY 2018 budget less than one year ago. Put another way, the lifecycle cost for WFIRST is the same now as it was two years ago and has been described as both reasonable and credible by numerous review panels.

Marvel worries that the administration’s proposal to scale back federal investment in the nation’s exploration of the universe and terminate WFIRST risks undermining future decadal surveys and other community-based priority-setting processes. “These efforts to achieve community consensus on research priorities are vital to ensuring the maximum return on public and private investments in the astronomical sciences,” Marvel says. “The cancellation of WFIRST would set a dangerous precedent and severely weaken a decadal-survey process that has established collective scientific priorities for a world-leading program for a half century. Such a move would also sacrifice US leadership in space-based dark energy, exoplanet, and survey astrophysics. We cannot allow such drastic damage to the field of astronomy, the impacts of which would be felt for more than a generation.”

The AAS will defend the important role of the decadal surveys in helping set federal spending priorities, to explain the scientific promise of the top-ranked WFIRST mission, and to share our excitement for the field of astrophysics, which has never been more ripe for discovery from the search for life elsewhere in the universe to understanding where we came from and where we’re going. “We look forward to working with Congress to restore funding for WFIRST and for NASA astrophysics overall,” Donahue concludes.
__________________________________________________________________________

David Spergel, former chairman of the academy’s Space Study Board, noted that in planning their own programs, other countries depended on the United States to follow the advice of the National Academy.

“A handful of people within the bureaucracy” and outside of NASA, he went on, “have overturned decades of community-driven processes and tried to set the direction for space astronomy.”

Astronomers have hungered for a space mission to investigate dark energy ever since 1998, when observations of the exploding stars known as supernovae indicated that the expansion of the universe was speeding up, the distant galaxies were shooting away faster and faster from us as cosmic time went on. It is as if, when you dropped your car keys, they shot up to the ceiling.

The discovery won three American astronomers the Nobel Prize. The fate of the universe, as well as the nature of physics, scientists say, depends on the nature of this dark energy.

Physicists have one ready-made explanation for this behavior, but it is a cure that many of them think is worse than the disease: a fudge factor invented by Einstein in 1917 called the cosmological constant. He suggested, and quantum theory has subsequently confirmed, that empty space could exert a repulsive force, an anti-gravity, blowing things apart.

If so, as the universe grows, it will expand faster and faster and run away from itself. Eventually other galaxies would be flying away so fast that we couldn’t see them. The universe would become dark and cold. The cosmologist Lawrence Krauss of Arizona State once described this as “the worst possible universe.”

If on the other hand, some previously unsuspected force field is tinkering with the galaxies and space-time, the effect could shut off or even reverse over the eons.

Or maybe we just don’t understand gravity.

Dark energy, said Frank Wilczek, a Nobel laureate from the Massachusetts Institute of Technology, “is the most mysterious fact in all of physical science, the fact with the greatest potential to rock the foundations.”

The astronomers who made this discovery were using the exploding stars known as Type 1a supernovae as cosmic distance markers to track the expansion rate of the universe.

Since then, other tools have emerged by which astronomers can also gauge dark energy by how it retards the growth of galaxies and other structures in the universe.

Way back in 1999, Saul Perlmutter of the Lawrence Berkeley Laboratory, one of dark energy’s discoverers, proposed a space mission known as SNAP (Supernova Acceleration Probe) to do just that.

In 2008, NASA and the Energy Department budgeted $600 million, not including launching costs, for a mission and the call went out for proposals. But NASA and the Energy Department found it hard to collaborate and a working group of dark-energy scientists could not come up with a design that would fit in the budget. In 2010, a committee of the National Academy of Sciences cobbled together several competing proposals that would do the trick. Paul Schechter, an M.I.T. astronomer involved in the work called it Wfirst, for Wide Field Infrared Survey Telescope. The acronym had a double meaning: “W” is the name for a crucial parameter that measures the virulence of dark energy. But the telescope would also search for exoplanets — planets beyond our solar system. In its report, “New Worlds, New Horizons,” the committee gave this mission the highest priority in space science for the next decade. But NASA would have no money to start on this project until it finished building the James Webb Space Telescope, the successor to the vaunted Hubble Space Telescope. Shortly after the academy’s deliberations, the space agency admitted that the Webb project had been mismanaged. The telescope, which had been set for a 2014 launching, would require at least another$1.6 billion and several more years to finish. The Webb will search out the first stars and galaxies to have formed in the universe, but is not designed for dark energy. It is now on course to be launched next year.

WFIRST would have to wait.

To take up the slack until 2025 — or whenever the American mission can finally fly — the space agency bought a share in a European dark-energy mission known as Euclid, now scheduled to launch in 2021. But Euclid is not as comprehensive as Wfirst would be; it will not use supernovas, for example.

ESA/NASA Euclid spacecraft

The story took another dramatic twist in June 2012, capturing headlines when the National Reconnaissance Office, which operates spy satellites, offered NASA a leftover telescope, essentially a close relative of the Hubble, that had been designed to look down instead of up.

It had a wide field of view, which could enable inspecting large areas of the heavens for supernovae.

Its primary mirror — like the Hubble 94 inches in diameter — is twice as big as the one that was being contemplated for Wfirst, giving it four times the light-gathering power and a deep reach into the cosmos.

The gift would save them the cost of fashioning a whole new telescope, but it was not without strings. As several astronomers pointed out, using a bigger telescope would mean a bigger, more expensive camera and more complicated back-end optics would have to be built. Nevertheless, the Academy bought into the idea.

Lately another controversial element has been added to the mission, a coronagraph, which could be used to block the light from a star so that faint planets near them can be discerned.

Last summer an independent review panel appointed by NASA and led by Fiona Harrison, a professor at the California Institute of Technology, endorsed the mission’s basic science goals and methodology while cautioning against mission creep that could cause its costs to balloon.

The ball is now in Congress’s court.

Michael Turner, a cosmologist at the University of Chicago, said, “While one never wants to hear that someone important has recommended cancellation of your favorite project, I believe that like last year, Congress will be doing the budget writing. I hope and believe that Congress will be wiser.”

Stem Education Coalition

## Science Magazine: NASA weighs trimming WFIRST to hold down costs

The proposed Wide Field Infrared Survey Telescope. NASA

Oct. 23, 2017
Daniel Clery

NASA will have to scale back its next big orbiting observatory to avoid busting its budget and affecting other missions, an independent panel says. The Wide Field Infrared Survey Telescope (WFIRST) is due for launch in the mid-2020s. But 1 year after NASA gave the greenlight its projected cost is $3.6 billion, roughly 12% overbudget. “I believe reductions in scope and complexity are needed,” Thomas Zurbuchen, head of NASA’s Science Mission Directorate in Washington, D.C., wrote in a memo that NASA released last Thursday. Designed to investigate the nature of dark energy and study exoplanets, WFIRST was chosen by the astronomy community as its top space-based mission priority in the 2010 decadal survey entitled New Worlds, New Horizons in Astronomy and Astrophysics. But the start of the project was initially delayed by the huge overspend on its predecessor, the James Webb Space Telescope, which will be launched in 2019. NASA/ESA/CSA Webb Telescope annotated Then last year, a midterm review of the 2010 decadal survey warned that WFIRST could go the same way and advised NASA to form a panel of independent experts to review the project. NASA assembled that panel in April this year and it recently submitted its conclusions. The agency has not released its report, as it is due to be discussed by the Committee for Astronomy and Astrophysics of the National Academies of Sciences, Engineering, and Medicine this week, but it did release a memo from Zurbuchen to Christopher Scolese, director of the Goddard Space Flight Center in Greenbelt, Maryland, which is leading the project. In it, Zurbuchen directs the lab “to study modifying the current WFIRST design … to reduce cost and complexity sufficient to have a cost estimate consistent with the$3.2 billion cost target [set last year].” Though the panel heaped praise on the WFIRST team for the work done so far, according to Zurbuchen’s memo, it faulted NASA managers for creating several challenges that have made the project “more complicated than originally anticipated.”

Paul Hertz, head of NASA’s astrophysics division, told ScienceInsider that one major demand was enlarging the spacecraft to accommodate a 2.4-meter mirror that the National Reconnaissance Office donated in 2012. Another was adding an instrument called a coronagraph.

WFIRST, which will have the sensitivity of the Hubble Space Telescope but with 100 times its field of view, was originally designed to survey the sky for signs of cosmic acceleration caused by dark energy. But when exoplanet researchers realized it would also benefit their field they lobbied for the inclusion of a coronagraph. This device acts as a mask inside the telescope to block out the glaring brightness of a star and reveal any dim planets around it.

NASA also decided to split the ground segment for the mission between the Space Telescope Science Institute in Baltimore, Maryland, and the California Institute of Technology in Pasadena.

And in an act of future-proofing, NASA wanted WFIRST to carry equipment making it compatible with a starshade, a proposed spacecraft that can be stationed at a distance to block out starlight and reveal exoplanets (more effectively than a coronagraph). “All these things added complexity,” Hertz says.

Zurbuchen’s memo to Scolese directs the lab to retain the basic elements of the mission—the 2.4-meter mirror, widefield camera, and coronagraph—but to seek cost-saving “reductions.” Hertz says this will require reducing the capabilities of instruments but ensuring they remain “above the science floor laid down by the decadal survey.” The coronagraph will be recategorized as a “technology demonstration instrument,” removing the burden of achieving a scientific target. The change will also save money, Hertz explains.

Hertz says exoplanet researchers shouldn’t worry about the proposed changes. “We know we’ll get good science out of the coronagraph. We’ll be able to see debris disks, zodiacal dust, and exoplanets in wide orbits,” he says. Astronomers wanting to see Earth twins in the habitable zone may be disappointed, however.

Zurbuchen also asked project managers to save money in the ground segment and by letting industry build some components or subsystems. The WFIRST team will need to submit a revised design by February 2018, before vendors are chosen, to begin building the hardware.

If costs continue to escalate, Zurbuchen says in his memo, NASA may need to abandon the 2.4-meter mirror and revert to the original, cheaper design using a 1.5-meter one. “That is plan B,” says Hertz, “but we very much like the 2.4-meter mirror.”

Stem Education Coalition

## From NASA on tumblr: “A Wider Set of Eyes on the Universe”

After years of preparatory studies, we are formally starting an astrophysics mission designed to help unlock the secrets of the universe.
Introducing…
the Wide Field Infrared Survey Telescope, aka WFIRST.

With a view 100 times bigger than that of our Hubble Space Telescope, WFIRST will help unravel the secrets of dark energy and dark matter, and explore the evolution of the cosmos. It will also help us discover new worlds and advance the search for planets suitable for life.

WFIRST is slated to launch in the mid-2020s. The observatory will begin operations after traveling about one million miles from Earth, in a direction directly opposite the sun.

Telescopes usually come in two different “flavors” – you have really big, powerful telescopes, but those telescopes only see a tiny part of the sky. Or, telescopes are smaller and so they lack that power, but they can see big parts of the sky. WFIRST is the best of worlds.

No matter how good a telescope you build, it’s always going to have some residual errors. WFIRST will be the first time that we’re going to fly an instrument that contains special mirrors that will allow us to correct for errors in the telescope. This has never been done in space before!

Employing multiple techniques, astronomers will also use WFIRST to track how dark energy and dark matter have affected the evolution of our universe. Dark energy is a mysterious, negative pressure that has been speeding up the expansion of the universe. Dark matter is invisible material that makes up most of the matter in our universe.

Single WFIRST images will contain over a million galaxies! We can’t categorize and catalogue those galaxies on our own, which is where citizen science comes in. This allows interested people in the general public to solve scientific problems.

Stem Education Coalition

The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

## From astrobites: “Bubbles from reionization at the cosmic dawn”

Astrobites

Title: Dark-ages reionization & galaxy formation simulation XII: Bubbles at dawn
Authors: Paul Geil, Simon Mutch, Gregory Poole, Alan Duffy, Andrei Mesinger, and Stuart Wyithe
First Author’s Institution: University of Melbourne, Parkville, Victoria, Australia

Status: Submitted to MNRAS, open access

The early universe encompasses many scarcely understood phenomena both cosmological and astrophysical that we hope to begin exploring. This can be made possible by looking at the highly redshifted 21cm emission (see here for why this emission happens) from neutral hydrogen which puts these observations from the cosmic dawn relevant to today’s astrobite into the radio frequency range of 100-140 MHz. But this signal is notoriously faint, and requires some of the most sensitive instruments ever designed to observe it. Currently this is an emerging field where most of the instruments with the necessary sensitivity are only now entering the development stage. This certainly won’t stop us from understanding the potential pitfalls we may encounter along the way in measuring the early universe. We can of course anticipate how well we can detect this signal through simulations of the 21cm emission and our next generation radio telescopes.

Cosmic Dawn and Galactic Reionization Bubbles

When the first galaxies began to form they also began to emit UV radiation. This UV radiation reionized the surrounding neutral hydrogen, which means that it can no longer emit the 21cm emission. From our perspective when observing this we see large spherical holes (bubbles) begin to form over time, making a ‘Swiss cheese’-like effect at the largest scales. To make up for a lack of bubble observations, simulations of bubble formation from the Dark ages Reionization & Galaxy Formation Simulation (DRAGONS) (for an example see Fig. 1) were created.

Fig 1: Example of two galaxies with similar luminosities and solar mass from the DRAGON simulation. The progression of reionization of the galaxies is seen in the form of growing bubble size over redshift.

Using information about mean bubble size and luminosity from DRAGONS, a relationship between the two can be found. This helps us in sampling appropriate galaxies to survey from the future Wide-Field Infrared Survey Telescope High Latitude Survey (WFIRST-HLS).

NASA/WFIRST

Fig 2. shows that the mean bubble size \bar{R}, increases linearly with luminosity. (Another example of associating bubble size and luminosity can be seen in this astrobite.)

Fig. 2: The authors show through simulation of reionization bubbles around galaxies that they have a linear relationship between the mean bubble size \bar{R} and the UV magnitude M_{UV}

1cm Bubble Observing with the SKA

The Square Kilometer Array (SKA) is an upcoming radio interferometer array located in South Africa and Western Australia.

SKA-Square Kilometer Array

Murchison Widefield Array,SKA Murchison Widefield Array, Boolardy station in outback Western Australia, at the Murchison Radio-astronomy Observatory (MRO)

It will consist of 1 sq. km of collecting area, making it the most sensitive array to ever exist, and a perfect instrument for observing the 21cm signal. Observation of the 21cm signal is dependent on the differential brightness temperature, \delta T_b.

\delta T_b \propto x_{HI}(1+\delta)(1 – \frac{T_{\gamma}}{T_{S}})

The differential brightness temperature depends on the dark matter over-density \delta (small fluctuations in the density), the spin temperature T_S, the CMB temperature T_{\gamma}, and the fraction of neutral hydrogen x_{HI}. It’s important to note that \delta T_b is spatially dependent, as both \delta and x_{HI} depend on position.

For simulating the observation of the 21cm differential brightness temperature from the cosmic dawn, they use the SKA1-Low specifications which determine the sensitivity (see here for some basic interferometry) and observational hours required . But the sensitivity of the SKA isn’t enough, so stacking spectra (averaging observations over frequency) must be used. By focusing on high redshift galaxies (z > 9) predicted from the WFIRST-HLS, and stacking future SKA1-Low observations centered on these galaxies, the bubbles from reionization should be observable. An example of how likely these bubbles can be measured is seen in Fig. 3, which shows that the signal to noise ratio (SNR) grows considerably for stacking 100+ galaxy observations in the case where T_{S} >> T_{\gamma} (right).

Fig. 3: The SNR for observing reionization bubbles increases if more spectra are stacked (100,200,300) and if \delta T_b is saturated (right), which means \delta T_b >> T_{\gamma}.

It appears from the author’s results that imaging individual bubbles from reionization doesn’t seem too likely as there is too much uncertainty in redshift and a high sensitivity required from the radio interferometer. But the technique the authors of today’s astrobite describe of stacking spectra over many galaxies does appear to provide that extra sensitivity for a measurement. There is also the big caveat of this being an ideal case, because our observations of the early universe are troubled by bright galactic and extragalactic foregrounds. The work in this astrobite also demonstrates that making a measurement of reionization and its characteristic bubbles may rely on a synthesized approach e.g. using both 21cm and near infrared observations.

Stem Education Coalition

What do we do?

Astrobites is a daily astrophysical literature journal written by graduate students in astronomy. Our goal is to present one interesting paper per day in a brief format that is accessible to undergraduate students in the physical sciences who are interested in active research.

Reading a technical paper from an unfamiliar subfield is intimidating. It may not be obvious how the techniques used by the researchers really work or what role the new research plays in answering the bigger questions motivating that field, not to mention the obscure jargon! For most people, it takes years for scientific papers to become meaningful.
Our goal is to solve this problem, one paper at a time. In 5 minutes a day reading Astrobites, you should not only learn about one interesting piece of current work, but also get a peek at the broader picture of research in a new area of astronomy.

## From Universe Today: “Rise Of The Super Telescopes: The Wide Field Infrared Survey Telescope – WFIRST”

Universe Today

2 May , 2017
Evan Gough

NASA’s Wide Field Infrared Survey Telescope (WFIRST) will capture Hubble-quality images covering swaths of sky 100 times larger than Hubble does. These enormous images will allow astronomers to study the evolution of the cosmos. Its Coronagraph Instrument will directly image exoplanets and study their atmospheres. Credits: NASA/GSFC/Conceptual Image Lab

We humans have an insatiable hunger to understand the Universe. As Carl Sagan said, “Understanding is Ecstasy.” But to understand the Universe, we need better and better ways to observe it. And that means one thing: big, huge, enormous telescopes.

In this series we’ll look at the world’s upcoming Super Telescopes:

The Giant Magellan Telescope
The Overwhelmingly Large Telescope
The 30 Meter Telescope
The European Extremely Large Telescope
The Large Synoptic Survey Telescope
The James Webb Space Telescope
The Wide Field Infrared Survey Telescope

The Wide Field Infrared Survey Telescope (WFIRST)

It’s easy to forget the impact that the Hubble Space Telescope has had on our state of knowledge about the Universe. In fact, that might be the best measurement of its success: We take the Hubble, and all we’ve learned from it, for granted now. But other space telescopes are being developed, including the WFIRST, which will be much more powerful than the Hubble. How far will these telescopes extend our understanding of the Universe?

“WFIRST has the potential to open our eyes to the wonders of the universe, much the same way Hubble has.” – John Grunsfeld, NASA Science Mission Directorate

The WFIRST might be the true successor to the Hubble, even though the James Webb Space Telescope (JWST) is often touted as such.

NASA/ESA/CSA Webb Telescope annotated

But it may be incorrect to even call WFIRST a telescope; it’s more accurate to call it an astrophysics observatory. That’s because one of its primary science objectives is to study Dark Energy, that rather mysterious force that drives the expansion of the Universe, and Dark Matter, the difficult-to-detect matter that slows that expansion.

WFIRST will have a 2.4 meter mirror, the same size as the Hubble. But, it will have a camera that will expand the power of that mirror. The Wide Field Instrument is a 288-megapixel multi-band near-infrared camera. Once it’s in operation, it will capture images that are every bit as sharp as those from Hubble. But there is one huge difference: The Wide Field Instrument will capture images that cover over 100 times the sky that Hubble does.

Alongside the Wide Field Instrument, WFIRST will have the Coronagraphic Instrument. The Coronagraphic Instrument will advance the study of exoplanets. It’ll use a system of filters and masks to block out the light from other stars, and hone in on planets orbiting those stars. This will allow very detailed study of the atmospheres of exoplanets, one of the main ways of determining habitability.

WFIRST is slated to be launched in 2025, although it’s too soon to have an exact date. But when it launches, the plan is for WFIRST to travel to the Sun-Earth LaGrange Point 2 (L2.)

LaGrange Points map. NASA

L2 is a gravitationally balanced point in space where WFIRST can do its work without interruption. The mission is set to last about 6 years.

Probing Dark Energy

“WFIRST has the potential to open our eyes to the wonders of the universe, much the same way Hubble has,” said John Grunsfeld, astronaut and associate administrator of NASA’s Science Mission Directorate at Headquarters in Washington. “This mission uniquely combines the ability to discover and characterize planets beyond our own solar system with the sensitivity and optics to look wide and deep into the universe in a quest to unravel the mysteries of dark energy and dark matter.”

In a nutshell, there are two proposals for what Dark Energy can be. The first is the cosmological constant, where Dark Energy is uniform throughout the cosmos. The second is what’s known as scalar fields, where the density of Dark Energy can vary in time and space.

We used to think that the Universe expanded at a steady rate. Then in the 1990s we discovered that the expansion had accelerated. Dark Energy is the name given to the force driving that expansion. Image: NASA/STSci/Ann Feild

Since the 1990s, observations have shown us that the expansion of the Universe is accelerating. That acceleration started about 5 billion years ago. We think that Dark Energy is responsible for that accelerated expansion. By providing such large, detailed images of the cosmos, WFIRST will let astronomers map expansion over time and over large areas. WFIRST will also precisely measure the shapes, positions and distances of millions of galaxies to track the distribution and growth of cosmic structures, including galaxy clusters and the Dark Matter accompanying them. The hope is that this will give us a next level of understanding when it comes to Dark Energy.

If that all sounds too complicated, look at it this way: We know the Universe is expanding, and we know that the expansion is accelerating. We want to know why it’s expanding, and how. We’ve given the name ‘Dark Energy’ to the force that’s driving that expansion, and now we want to know more about it.

Probing Exoplanets

Dark Energy and the expansion of the Universe is a huge mystery, and a question that drives cosmologists. (They really want to know how the Universe will end!) But for many of the rest of us, another question is even more compelling: Are we alone in the Universe?

There’ll be no quick answer to that one, but any answer we find begins with studying exoplanets, and that’s something that WFIRST will also excel at.

Artist’s concept of the TRAPPIST-1 star system, an ultra-cool dwarf that has seven Earth-size planets orbiting it. We’re going to keep finding more and more solar systems like this, but we need observatories like WFIRST to understand the planets better. Credits: NASA/JPL-Caltech

“WFIRST is designed to address science areas identified as top priorities by the astronomical community,” said Paul Hertz, director of NASA’s Astrophysics Division in Washington. “The Wide-Field Instrument will give the telescope the ability to capture a single image with the depth and quality of Hubble, but covering 100 times the area. The coronagraph will provide revolutionary science, capturing the faint, but direct images of distant gaseous worlds and super-Earths.”

“The coronagraph will provide revolutionary science, capturing the faint, but direct images of distant gaseous worlds and super-Earths.” – Paul Hertz, NASA Astrophysics Division

The difficulty in studying exoplanets is that they are all orbiting stars. Stars are so bright they make it impossible to see their planets in any detail. It’s like staring into a lighthouse miles away and trying to study an insect near the lighthouse.

The Coronagraphic Instrument on board WFIRST will excel at blocking out the light of distant stars. It does that with a system of mirrors and masks. This is what makes studying exoplanets possible. Only when the light from the star is dealt with, can the properties of exoplanets be examined.

This will allow detailed measurements of the chemical composition of an exoplanet’s atmosphere. By doing this over thousands of planets, we can begin to understand the formation of planets around different types of stars. There are some limitations to the Coronagraphic Instrument, though.

The Coronagraphic Instrument was kind of a late addition to WFIRST. Some of the other instrumentation on WFIRST isn’t optimized to work with it, so there are some restrictions to its operation. It will only be able to study gas giants, and so-called Super-Earths. These larger planets don’t require as much finesse to study, simply because of their size. Earth-like worlds will likely be beyond the power of the Coronagraphic Instrument.

These limitations are no big deal in the long run. The Coronagraph is actually more of a technology demonstration, and it doesn’t represent the end-game for exoplanet study. Whatever is learned from this instrument will help us in the future. There will be an eventual successor to WFIRST some day, perhaps decades from now, and by that time Coronagraph technology will have advanced a great deal. At that future time, direct snapshots of Earth-like exoplanets may well be possible.

But maybe we won’t have to wait that long.

There is a plan to boost the effectiveness of the Coronagraph on WFIRST that would allow it to image Earth-like planets. It’s called the EXO-S Starshade.

The EXO-S Starshade is a 34m diameter deployable shading system that will block starlight from impairing the function of WFIRST. It would actually be a separate craft, launched separately and sent on its way to rendezvous with WFIRST at L2. It would not be tethered, but would orient itself with WFIRST through a system of cameras and guide lights. In fact, part of the power of the Starshade is that it would be about 40,000 to 50,000 km away from WFIRST.

Dark Energy and Exoplanets are priorities for WFIRST, but there are always other discoveries awaiting better telescopes. It’s not possible to predict everything that we’ll learn from WFIRST. With images as detailed as Hubble’s, but 100 times larger, we’re in for some surprises.

“This mission will survey the universe to find the most interesting objects out there.” – Neil Gehrels, WFIRST Project Scientist

“In addition to its exciting capabilities for dark energy and exoplanets, WFIRST will provide a treasure trove of exquisite data for all astronomers,” said Neil Gehrels, WFIRST project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This mission will survey the universe to find the most interesting objects out there.”

With all of the Super Telescopes coming on line in the next few years, we can expect some amazing discoveries. In 10 to 20 years time, our knowledge will have advanced considerably. What will we learn about Dark Matter and Dark Energy? What will we know about exoplanet populations?

Right now it seems like we’re just groping towards a better understanding of these things, but with WFIRST and the other Super Telescopes, we’re poised for more purposeful study.

Stem Education Coalition

## From Cornell: Women in STEM – “The Space between Stars and Galaxies” Rachel E. Bean

Cornell University

10.5.16
Jackie Swift

Rachel E. Bean

Mystery shrouds the birth of our universe. In a fraction of a second, the universe transformed from a size smaller than a subatomic proton through expanding exponentially faster than the speed of light, according to the Big Bang theory. At the heart of this event lies the explanation for all the constituents of the cosmos today. If the moment of the Big Bang can be understood, we may finally have the theory of everything that can reconcile the quantum Standard Model of particle physics with Einstein’s general theory of relativity, which holds that gravity is a result of the curvature of space and time.

Even the most powerful particle physics experiments on Earth don’t have enough clout to recreate the conditions in the early universe. We can find evidence of them, however, in the cosmic microwave background (CMB), which functions like a fossil remnant of that very early universe, says Rachel E. Bean, Astronomy.

CMB per ESA/Planck

“The CMB was made about 400 thousand years after the start of the universe,” she says. “It’s a pristine glimpse of what the universe was like at that instant, and buried inside that signal is a signature of what happened a trillionth of a second after the Big Bang.”

The Early Universe and the Cosmic Microwave Background

The CMB is a faint glow in the microwave wavelength that can be seen with telescopes that detect microwave radiation in the space between stars and galaxies. It has been traveling toward us for 13 billion years carrying information about those early moments. “At that time the universe was governed by quantum physics at a level that we don’t think we fully understand,” Bean says. “As we go back in time, the universe gets smaller, hotter and denser. At its very earliest instances, it was at temperatures and densities that we can never recreate on earth.”

In an effort to understand physics at those extreme properties, Bean looks for tiny temperature fluctuations in the CMB. These were generated a trillionth of a second after the Big Bang during a process called primordial inflation when the universe is thought to have expanded faster than the speed of light for a brief time. “We have to describe how quantum properties behave with gravity and space and time,” says Bean. “We don’t know how to do that. The only way we can try to figure this out is to look at these very early moments.” Bean hopes to connect these temperature fluctuations in the CMB to one of the potential theories—especially string theory—that are candidates to reconcile quantum mechanics and the general theory of relativity.

The CMB can also tell scientists about the effects of gravity on objects through time.

“The CMB has essentially seen everything that has been created since it was formed,” says Bean. “It traveled through the universe as it evolved, and as it did that it had the signatures of that history imbued upon it.”

Massive Galaxy Clusters, Dark Matter, and Dark Energy

Bean is interested in the information the CMB carries about its travels through the most massive objects in the universe: galaxy clusters. These are about a thousand times larger than our galaxy. As the CMB passes through a cluster, the heat of the cluster and its movement leaves a sort of Doppler shift on the frequency of the light from the CMB. “We can use the CMB as a motion detector for these clusters,” Bean explains. “We can see how fast they were moving when the CMB passed through them. This is useful because those clusters were moving because of the properties of gravity at that time.”

Bean will also be looking for evidence of the effects of dark matter and dark energy—two components of the universe that we cannot see. They do not emit light or absorb it, and none of our instruments can detect them. Scientists think that 95 percent of the matter in the universe is dark matter and dark energy, which change the properties of how gravity behaves. The only way to learn about the properties of these components is to look at their impact on astrophysical bodies such as galaxy clusters, Bean says. “By looking at how fast the galaxy clusters were moving in the past, we can test the properties of gravity and dark matter.”

Big Bold Telescopes, Up Soon

Astronomers will be able to do that in unparalleled detail over the next decade when four new telescopic surveys come online. These large-scale structure surveys will look at millions to billions of galaxies. They will either take multicolor images of them, revealing through color different physical properties, or they will record the galaxies’ spectra, the emission or absorption lines of light of particular wavelengths, which pinpoint the galaxies’ positions in space. “We’re going to be able to survey out billions of light years to be able to understand the structure of our universe with unprecedented precision,” Bean says.

Two of the telescopes will be ground-based and two will be space-based. Bean is the leader of an international collaboration of approximately 500 scientists—the LSST Dark Energy Science Collaboration—that will be using the data from one of the ground-based photometric imaging telescopes, the Large Synoptic Survey Telescope (LSST), which is an international venture led by two United States agencies, the National Science Foundation and the United States Department of Energy.

LSST/Camera, built at SLAC

LSST telescope, currently under construction at Cerro Pachón Chile

The LSST will be commissioned in 2019 with the first surveys coming online in 2021. Bean is scrambling to prepare for the challenge of analyzing all the anticipated data. “It’s going to be like a massive gush,” Bean says. “If we’re able to analyze it properly, we will get orders of magnitude improvement in our understanding of the properties of the cosmos.”

The LSST will share the ground-based spotlight with another state-of-the-art telescope, the Dark Energy Spectroscopic Instrument (DESI), a United States Department of Energy initiative, which will come online in 2019.

“LBL/DESI spectroscopic instrument on the Mayall 4-meter telescope at Kitt Peak National Observatory starting in 2018

The final two telescopes, both space-based, will be launched in the next decade: the European Space Agency’s Euclid in 2021 and the National Aeronautics and Space Administration’s Wide Field Infrared Survey Telescope (WFIRST) in the mid-twenties.

ESA/Euclid spacecraft

NASA/WFIRST

Bean plans to take the new information on the nature of galaxies provided by the four surveys and combine it with data on the motions of galaxy clusters gleaned from the CMB. Altogether they should help her and other cosmologists uncover the true properties of dark matter and dark energy, “We’ll be able to test whether general relativity holds on a cosmic scale,” Bean says. “That’s really exciting!”

Stem Education Coalition
Once called “the first American university” by educational historian Frederick Rudolph, Cornell University represents a distinctive mix of eminent scholarship and democratic ideals. Adding practical subjects to the classics and admitting qualified students regardless of nationality, race, social circumstance, gender, or religion was quite a departure when Cornell was founded in 1865.

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On the Ithaca campus alone nearly 20,000 students representing every state and 120 countries choose from among 4,000 courses in 11 undergraduate, graduate, and professional schools. Many undergraduates participate in a wide range of interdisciplinary programs, play meaningful roles in original research, and study in Cornell programs in Washington, New York City, and the world over.

## From Astro Watch: “NASA’s WFIRST Spacecraft Expected to Be a Huge Step Forward in Our Understanding of Dark Matter”

Astro Watch

NASA/WFIRST telescope

NASA’s Wide Field Infrared Survey Telescope (WFIRST) could be a space observatory of the future, destined for great discoveries in the field of astrophysics. With a view about 100 times bigger than that of the iconic Hubble Space Telescope, WFIRST is expected to yield crucial results about the still-elusive dark matter and dark energy.

NASA/ESA Hubble Telescope

Perplexing astronomers for years, dark matter and dark energy could soon reveal their real nature. WFIRST is currently being designed to address the most baffling questions about these mysterious substances, together accounting for about 95 percent of the mass-energy of the universe. The spacecraft could provide a major improvement in our understanding of this subject.

“WFIRST will survey large areas of the sky measuring the effects of dark matter on the distribution of galaxies in the universe. It will also observe distant Type Ia supernovae to use them as tracers of dark matter and dark energy. It will provide a huge step forward in our understanding of dark matter and dark energy,” Brooke Hsu of NASA’s Goddard Space Flight Center in Greenbelt, Md. told Astrowatch.net.

WFIRST is managed at Goddard, with participation by the Jet Propulsion Laboratory (JPL) in Pasadena, California, the Space Telescope Science Institute in Baltimore, the Infrared Processing and Analysis Center, also in Pasadena, and a science team comprised of members from U.S. research institutions across the country.

The spacecraft is currently in Phase A of preparations. The purpose of this phase is to develop the mission requirements and architecture necessary to meet the programmatic requirements and constraints on the project and to develop the plans for the Preliminary Design phase. The preparations are on track for a mid-2020 launch. After liftoff, the telescope will travel to a gravitational balance point known as Earth-Sun L2, located about one million miles from Earth in a direction directly opposite the Sun.

LaGrange Points map

Operating at L2, WFIRST will study dark matter and dark energy with several techniques. The High Latitude Spectroscopic Survey will measure accurate distances and positions of a very large number of galaxies. It will measure the growth of large structure of the universe, testing theory of Einstein’s General Relativity.

“It will perform large surveys of galaxies and galaxy clusters to see the effects of dark matter and energy on their shapes and distributions in the universe. All told, more than a billion galaxies will be observed by WFIRST,” Hsu revealed.

The spacecraft will conduct the Type Ia Supernovae (SNe) Survey which will use type Ia SNe as “standard candles” to measure absolute distances. Calculating the distance to and redshift of the SNe provides another means of measuring the evolution of dark energy over time, providing a cross-check with the high latitude surveys.

“It will observe Type Ia supernovae to determine their distance and properties. More than 2,000 supernovae will be observed,” Hsu said.

WFIRST will also carry out the High Latitude Imaging Survey that will measure the shapes and distances of a very large number of galaxies and galaxy clusters. This survey is expected to determine both the evolution of dark energy over time as well as provide another independent measurement of the growth of large structure of the universe.

But WFIRST is not only about astrophysics. The infrared telescope will also have a chance to prove its usefulness as an exoplanet hunter. It will use microlensing techniques to expand our catalog of known extrasolar planets and will directly characterize these alien worlds using coronagraphy.

“WFIRST will study exoplanets with two very different techniques: microlensing and coronagraph. The mission will stare at the a dense star region toward the direction of the center of our Milky Way galaxy to observe microlensing events. These brightenings caused when two stars exactly align and also provide a tally of the exoplanets around the stars. Over 2,000 exoplanets will be detected this way,” Hsu noted.

To fulfill its scientific goals, WFIRST will be equipped in a 2.4-meter telescope hosting two instruments: the Wide-Field Instrument (WFI) and a high contrast coronagraph. WFI will provide the wide-field imaging and slitless spectroscopic capabilities required to perform the Dark Energy, Exoplanet Microlensing, and near-infrared (NIR) surveys while the coronagraph instrument is being designed for the exoplanet high contrast imaging and spectroscopic science.

“The Wide Field Instrument provides wide-field imaging and spectroscopy in support of the dark energy and microlensing surveys and integral field spectroscopy in support of the supernova survey,” Hsu said.

The coronagraph will be able to detect more than 50 exoplanets and observe their properties.

“It will be a huge leap forward compared to current instruments. Most exciting will be spectral observations of the light from the planets to see what the properties are of the atmospheres and possibly surfaces. Searches will be made for signatures of life on the planets,” Hsu said.

By operating WFIRST, NASA hopes to make major discoveries in the areas of dark matter and energy, exoplanets and general astrophysics. The agency expects to learn the nature of dark matter and energy to determine what they are.

“We will survey the sky to find the most exotic and interesting galaxies, black holes, and stars. We will take a census of exoplonets that are beyond on astronomical unit from their stars, a region that Kepler is not able to survey. We will make the first sensitive direct observation of nearby exoplanets and find what their nature is and if there are signatures of life,” Hsu concluded.

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