Tagged: space.com Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 9:54 am on November 21, 2014 Permalink | Reply
    Tags: , , , , , , space.com   

    From SPACE.com: “Planet Uranus: Facts About Its Name, Moons and Orbit” 

    space-dot-com logo

    SPACE.com

    November 18, 2014
    Charles Q. Choi

    Uranus is the seventh planet from the sun and the first to be discovered by scientists. Although Uranus is visible to the naked eye, it was long mistaken as a star because of the planet’s dimness and slow orbit. The planet is also notable for its dramatic tilt, which causes its axis to point nearly directly at the sun.

    ur

    British astronomer William Herschel discovered Uranus accidentally on March 13, 1781, with his telescope while surveying all stars down to those about 10 times dimmer than can be seen by the naked eye. One “star” seemed different, and within a year Uranus was shown to follow a planetary orbit.

    Uranuswas named after the Greek sky deity Ouranos, the earliest of the lords of the heavens. It is the only planet to be named after a Greek god rather than a Roman one. Before the name was settled on, many names had been proposed for the new planet, including Hypercronius (“above Saturn”), Minerva (the Roman goddess of wisdom), and Herschel, after its discoverer. To flatter King George III of England, Herschel himself offered Georgium Sidus (“The Georgian Planet”) as a name, but that idea was unpopular outside of England and George’s native Hanover. German astronomer Johann Bode, who detailed Uranus’ orbit, gave the planet its ultimate name.

    Physical characteristics

    Uranusis blue-green in color, the result of methane in its mostly hydrogen-helium atmosphere. The planet is often dubbed an ice giant, since 80 percent or more of its mass is made up of a fluid mix of water, methane, and ammonia ices.

    Unlike the other planets of the solar system, Uranus is tilted so far that it essentially orbits the sun on its side, with the axis of its spin nearly pointing at the star. This unusual orientation might be due to a collision with a planet-size body, or several small bodies, soon after it was formed.

    This unusual tilt gives rise to extreme seasons roughly 20 years long, meaning that for nearly a quarter of the Uranian year, equal to 84 Earth-years, the sun shines directly over each pole, leaving the other half of the planet to experience a long, dark, cold winter.

    The magnetic poles of most planets are typically lined up with the axis along which it rotates, but Uranus’ magnetic field is tilted, with its magnetic axis tipped over nearly 60 degrees from the planet’s axis of rotation. According to Norman F. Ness, et al, in an article in the journal Science, this leads to a strangely lopsided magnetic field for Uranus, with the strength of the field at the northern hemisphere’s surface being up to more than 10 times that of the strength at the southern hemisphere’s surface, affecting the formation of the auroras.

    Orbital characteristics

    Average distance from the sun: 1,783,939,400 miles (2,870,972,200 kilometers). By comparison: 19.191 times that of Earth

    Perihelion (closest approach to the sun): 1,699,800,000 miles (2,735,560,000 km). By comparison: 18.60 times that of Earth

    Aphelion (farthest distance from sun): 1,868,080,000 miles (3,006,390,000 km). By comparison: 19.76 times that of Earth
    The planet Uranus, seventh planet from the sun, is a giant ball of gas and liquid and was the first planet discovered with a telescope.

    ur
    Credit: Karl Tate, SPACE.com

    Composition & structure

    Atmospheric composition (by volume): 82.5 percent hydrogen, 15.2 percent helium, 2.3 percent methane

    Magnetic field: Magnetic pole tilt compared to rotational axis: 58.6 degrees

    Composition: The overall composition of Uranus is, by mass, thought to be about 25 percent rock, 60 to 70 percent ice, and 5 to 15 percent hydrogen and helium.

    Internal structure: Mantle of water, ammonia and methane ices; core of iron and magnesium-silicate
    Orbit & rotation

    Axial tilt: 97.77 degrees, compared to Earth’s 23.5 degrees

    Seasonal cycle & length: Approximately 21 years per season

    Orbital period: Approximately 84 Earth years
    Uranus’ climate

    The extreme axial tilt Uranus experiences can give rise to unusual weather. As sunlight reaches some areas for the first time in years, it heats up the atmosphere, triggering gigantic springtime storms roughly the size of North America, according to NASA.

    Ironically, when Voyager 2 first imaged Uranus in 1986 at the height of summer in its south, it saw a bland-looking sphere with only about 10 or so visible clouds, leading to it to be dubbed “the most boring planet,” writes astronomer Heidi Hammel in The Ice Giant Systems of Uranus and Neptune, a chapter in Solar System Update (Springer, 2007). It took decades later, when advanced telescopes such as Hubble came into play and the seasons changed, to see extreme weather on Uranus, where fast-moving winds can reach speeds of up to 560 miles (900 kilometers) per hour.

    NASA Voyager 2
    NASA/Voyager 2

    NASA Hubble Telescope
    NASA/ESA Hubble

    The rings of Uranus

    The rings of Uranus were the first to be seen after Saturn’s. They were a significant discovery, because it helped astronomers understand that rings are a common feature of planets, not merely a peculiarity of Saturn.

    Uranus possesses two sets of rings. The inner system of rings consists mostly of narrow, dark rings, while an outer system of two more-distant rings, discovered by the Hubble Space Telescope, are brightly colored, one red, one blue. Scientists have now identified 13 known rings around Uranus.
    Uranus’ moons

    Uranus has 27 known moons. Instead of being named after figures from Greek or Roman mythology, its first four moons were named after magical spirits in English literature, such as William Shakespeare’s “A Midsummer Night’s Dream” and Alexander Pope’s “The Rape of the Lock.” Since then, astronomers have continued this tradition, drawing names for the moons from the works of Shakespeare or Pope.

    Oberon and Titania are the largest Uranian moons, and were the first to be discovered, by Herschel in 1787. William Lassell, who was the first to see a moon orbiting Neptune, discovered the next two, Ariel and Umbriel. Then nearly a century passed before Miranda was found in 1948.

    Then, Voyager 2 visited the Uranian system in 1986 and found an additional 10, all just 16 to 96 miles (26-154 km) in diameter — Juliet, Puck, Cordelia, Ophelia, Bianca, Desdemona, Portia, Rosalind, Cressida and Belinda — and each roughly made half of water ice and half of rock. Since then, astronomers using the Hubble Space Telescope and ground-based observatories have raised the total to 27 known moons, and spotting these was tricky — they are as little as 8 to 10 miles (12 to 16 km) across, blacker than asphalt, and nearly 3 billion miles (4.8 billion km) away.

    Between Cordelia, Ophelia and Miranda is a swarm of eight small satellites crowded together so tightly that astronomers don’t yet understand how the little moons have managed to avoid crashing into each other. Scientists suspect there might still be more moons, closer to Uranus than any known.

    In addition to moons, Uranus may also have a collection of Trojan asteroids — objects that share the same orbit as the planet — in a special region known as a Lagrangian point. The first was discovered in 2013, despite claims that the planet’s Langrangian point would be too unstable to host such bodies.

    Research & exploration

    NASA’s Voyager 2 was the first and as yet only spacecraft to visit Uranus. It discovered 10 previously unknown moons, and investigated its unusually tilted magnetic field.

    In 2013, the Planetary Science Decadal Survey recommended NASA consider a mission to the icy planet.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 9:31 am on November 21, 2014 Permalink | Reply
    Tags: , , , , , , space.com   

    From Science Daily: “How to estimate the magnetic field of an exoplanet” 

    ScienceDaily Icon

    [Similar material to an earlier post; but a different slant.]

    Science Daily

    November 20, 2014
    Source: Lomonosov Moscow State University

    Scientists developed a new method which allows to estimate the magnetic field of a distant exoplanet, i.e., a planet, which is located outside the Solar system and orbits a different star. Moreover, they managed to estimate the value of the magnetic moment of the planet HD 209458b.The group of scientists including one of the researchers of the Lomonosov Moscow State University (Russia) published their article in the Science magazine.

    2
    Size comparison of HD 209458 b with Jupiter.

    hj
    Artist’s interpretation of Planet HD 209458b. Scientists have now estimated the value of the magnetic moment of the planet HD 209458b.
    Credit: NASA/ESA/CNRS/Alfred Vidal-Madjar

    In the two decades which passed since the discovery of the first planet outside the Solar system, astronomers have made a great progress in the study of these objects. While 20 years ago a big event was even the discovery of a new planet, nowadays astronomers are able to consider their moons, atmosphere and climate and other characteristics similar to the ones of the planets in the Solar system. One of the important properties of both solid and gaseous planets is their possible magnetic field and its magnitude. On Earth it protects all the living creatures from the dangerous cosmic rays and helps animals to navigate in space.

    Kristina Kislyakova of the Space Research Institute of the Austrian Academy of Sciences in Graz together with an international group of physicists for the first time ever was able to estimate the value of the magnetic moment and the shape of the magnetosphere of the exoplanet HD 209458b. Maxim Khodachenko, a researcher at the Department of Radiation and computational methods of the Skobeltsyn Institute of Nuclear Physics of the Lomonosov Moscow State University, is also one of the authors of the article. He also works at the Space Research Institute of the Austrian Academy of Sciences.

    Planet HD 209458b (Osiris) is a hot Jupiter, approximately one third larger and lighter than Jupiter. It is a hot gaseous giant orbiting very close to the host star HD 209458. HD 209458b accomplishes one revolution around the host star for only 3.5 Earth days. It has been known to astronomers for a long time and is relatively well studied. In particular, it is the first planet where the atmosphere was detected. Therefore, for many scientists it has become a model object for the development of their hypotheses.

    Scientists used the observations of the Hubble Space Telescope of the HD 209458b in the hydrogen Lyman-alpha line at the time of transit, when the planet crosses the stellar disc as seen from Earth. At first, the scientists studied the absorption of the star radiation by the atmosphere of the planet. Afterwards they were able to estimate the shape of the gas cloud surrounding the hot Jupiter, and, based on these results, the size and the configuration of the magnetosphere.

    NASA Hubble Telescope
    NASA/ESA Hubble

    “We modeled the formation of the cloud of hot hydrogen around the planet and showed that only one configuration, which corresponds to specific values of the magnetic moment and the parameters of the stellar wind, allowed us to reproduce the observations,” explained Kristina Kislyakova.

    To make the model more accurate, scientists accounted for many factors that define the interaction between the stellar wind and the atmosphere of the planet: so-called charge exchange between the stellar wind and the neutral atmospheric particles and their ionization, gravitational effects, pressure, radiation acceleration, and the spectral line broadening.

    At present, scientists believe that the size of the atomic hydrogen envelope is defined by the interaction between the gas outflows from the planet and the incoming stellar wind protons. Similarly to Earth, the interaction of the atmosphere with the stellar wind occurs above the magnetosphere. By knowing the parameters of an atomic hydrogen cloud, one can estimate the size of the magnetosphere by means of a specific model.

    Since direct measurements of the magnetic field of exoplanets are currently impossible, the indirect methods are broadly used, for example, using the radio observations. There exist a number of attempts to detect the radio emission from the planet HD 209458b. However, because of the large distances the attempts to detect the radio emission from exoplanets have yet been unsuccessful.

    “The planet’s magnetosphere was relatively small being only 2.9 planetary radii corresponding to a magnetic moment of only 10% of the magnetic moment of Jupiter,” explained Kislyakova, a graduate of the Lobachevsky State University of Nizhny Novgorod. According to her, it is consistent with the estimates of the effectiveness of the planetary dynamo for this planet.

    “This method can be used for every planet, including Earth-like planets, if there exist an extended high energetic hydrogen envelope around them,” summarized Maxim Khodachenko.

    Journal Reference:

    K. G. Kislyakova, M. Holmstrom, H. Lammer, P. Odert, M. L. Khodachenko. Magnetic moment and plasma environment of HD 209458b as determined from Ly observations. Science, 2014; 346 (6212): 981 DOI: 10.1126/science.1257829

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ScienceDaily is one of the Internet’s most popular science news web sites. Since starting in 1995, the award-winning site has earned the loyalty of students, researchers, healthcare professionals, government agencies, educators and the general public around the world. Now with more than 3 million monthly visitors, ScienceDaily generates nearly 15 million page views a month and is steadily growing in its global audience.

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 4:43 pm on November 20, 2014 Permalink | Reply
    Tags: , , , , , space.com   

    From SPACE.com: “Unlocking the Secrets of an Alien World’s Magnetic Field” 

    space-dot-com logo

    SPACE.com

    November 20, 2014
    Charles Q. Choi

    The strength of an alien world’s magnetic field may have been deduced for the first time, by analyzing extraordinarily fast winds slamming against it from the planet’s star, researchers say.

    This research could help gauge the strength of other exoplanets‘ magnetic fields as well, scientists say.

    The magnetic field of a planet can influence its evolution in crucial ways. “It works as a shield against stellar wind particles, which erode the atmosphere, so it is important to know if this field is big or small,” said study lead author Kristina Kislyakova, a planetary scientist at the Austrian Academy of Sciences, in Graz.

    In order to find out magnetic details about exoplanets — planets beyond our own solar system — Kislyakova and her colleagues investigated HD 209458b, which orbits a sunlike star in the constellation Pegasus about 150 light-years from Earth. This alien world is only about 70 percent the mass of Jupiter, but nearly 40 percent wider.

    2
    Size comparison of HD 209458 b with Jupiter.

    HD 209458b is a “hot Jupiter,” a gas giant that orbits its star closer than Mercury does to the sun — specifically, HD 209458b circles its star at a distance of less than one-twentieth the distance between the sun and Earth. The extraordinary roasting that HD 209458b endures makes its atmosphere blow away like the tail of a comet. Astronomers have informally dubbed the world “Osiris,” after the Egyptian god torn to pieces by his evil brother Set.

    hj
    Artist’s concept of an evaporating “hot Jupiter” exoplanet.
    Credit: NASA’s Goddard Space Flight Center

    The researchers used NASA’s Hubble Space Telescope to analyze the spectrum of light from HD 209458b as it passed in front of its star. Oddly, the data revealed hydrogen atoms moving away extremely quickly from the exoplanet in a lopsided manner.

    NASA Hubble Telescope
    NASA/ESA HUbble

    To help explain the unusual way in which the hydrogen is blowing off HD 209458b, the scientists built a 3D model to account for all the known interactions between planetary atmospheres and stellar winds, the flow of particles that stream off stars. The model suggested the exoplanet had a magnetic field about 10 percent as strong as Jupiter’s, and that the stellar wind blowing onto the planet was moving at about 895,000 mph (1.44 million km/h).

    “The implication of these findings is improvement of our understanding of the worlds outside the solar system — some new light shed on bodies many light-years away from us,” Kislyakova told Space.com.

    These findings support prior research suggesting that hot Jupiters have relatively weak magnetic fields compared with their cooler gas giant cousins. Since hot Jupiters orbit very near their stars, they experience powerful gravitational pulls that likely slow the rates at which these hot Jupiters spin. This slower rotation should result in weaker magnetic fields, because a planet’s magnetic field “is generated most effectively in fast-rotating cores of planets,” Kislyakova said.

    The scientists detailed their findings online today (Nov. 20) in the journal Science.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 3:11 pm on November 19, 2014 Permalink | Reply
    Tags: , , , , Lunar Mission One, , space.com   

    From SPACE.com: “Private Moon Mission Aims to Drill Into Lunar South Pole by 2024″ 

    space-dot-com logo

    SPACE.com

    November 19, 2014
    Mike Wall

    A privately funded robotic moon mission intends to drill deep beneath the lunar surface in 2024, both to advance understanding of the solar system and to inspire future generations to get more involved in space science and exploration.

    th
    Artist’s concept of the robotic Lunar Mission One touching down at the moon’s south pole in 2024.
    Credit: Rawcut Television/Lunar Mission One

    If all goes according to plan, the newly announced Lunar Mission One will drill at least 65 feet (20 meters) — and perhaps as much as 330 feet (100 m) — underground at the moon’s south pole in 2024, collecting samples that should shed light on the formation of the Earth and moon, as well as the feasibility of a manned lunar outpost in the area, project organizers said.

    Going so deep underground will give scientists a look at pristine ancient rock untouched by cosmic radiation or meteorite impacts over the eons, the mission representatives added.

    “Lunar Mission One will make a huge contribution to our understanding of the origins of our planet and the moon, and will inspire a generation to learn more about space, science and engineering, in the same way that my generation was inspired by the Apollo moon landings,” David Iron, founder of Lunar Missions Ltd. and the Lunar Missions Trust, said in a statement.

    While the unmanned Lunar Mission One was just announced publicly Tuesday evening (Nov. 18), it has been in the works for the past seven years, project officials said.

    dr
    Artist’s concept of the privately funded Lunar Mission One drilling deep into the moon’s south pole. Mission representatives hope to collect samples from at least 65 feet (20 meters) underground.
    Credit: Rawcut Television/Lunar Mission One

    The United Kingdom-based mission aims to pay for its ambitious activities in several different ways, starting with a Kickstarter campaign that launched on Tuesday. Organizers hope the crowdfunding effort will raise about $950,000, which would fund initial development operations.

    People will also be able to purchase “digital memory boxes” — giving participants the chance to contribute to a time capsule that Lunar Mission One plans to bury as part of its work at the south pole of the moon. This time capsule will also contain a record of life on Earth and a chronicle of human history and civilization, project organizers said.

    Sales of digital memory boxes will continue for years, and mission representatives are counting on big international participation. Market research suggests that 1 percent of people around the world who can afford a digital memory box will buy one, potentially resulting in revenues of about $4.7 billion, mission representatives said.

    Any surplus money raised will be put into a charitable trust dedicated to funding future space science and exploration activities, the organizers added.

    Lunar Missions Ltd. runs Lunar Mission One with the assistance of a number of partner organizations, including RAL Space (part of the United Kingdom’s Science and Technology Facilities Council), University College London, The Open University in the United Kingdom and the Institute of Education in London.

    “Lunar Mission One is both ambitious and innovative, demonstrating an exciting way of enabling lunar exploration,” RAL Space Director Richard Holdaway said in a statement. “As well as direct exploration benefits, the mission will have longer-term advantages, including technological advances and knowledge.”

    To learn more about Lunar Mission One, go to http://www.lunarmissionone.com.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 10:33 am on November 19, 2014 Permalink | Reply
    Tags: , , , , , , space.com   

    From SPACE.com: “Asteroid Found with Rings! First-of-Its-Kind Discovery Stuns Astronomers (Video, Images)” 

    space-dot-com logo

    SPACE.com

    March 26, 2014
    Nola Taylor Redd

    Scientists have made a stunning discovery in the outer realm of the solar system — an asteroid with its own set of rings that orbits the sun between Saturn and Uranus. The space rock is the first non-planetary object ever found to have its own ring system, researchers say.

    The pair of space rock rings encircle the asteroid Chariklo. They were most likely formed after a collision scattered debris around the asteroid, according to a new study unveiled today (March 27). The asteroid rings also suggests the presence of a still-undiscovered moon around Chariklo that’s keeping them stable, researchers said.

    “We weren’t looking for a ring and didn’t think small bodies like Chariklo had them at all, so the discovery — and the amazing amount of detail we saw in the system — came as a complete surprise!” study leader Felipe Braga-Ribas, of the National Observatory in Brazil said in a statement today.

    Astronomers used seven telescopes, but just one revealed the pair of rings orbiting the rocky Chariklo. The asteroid’s 155-mile diameter (250 kilometers) is dwarfed by the giant gas planets, the only other bodies known to have rings.

    “This discovery shows that size is not important in order to have — or not have — rings,” Felipe Braga-Ribas, of the National Observatory in Brazil, told Space.com by email.

    An asteroid among giants

    On June 3, 2013, Braga-Ribas led a team of astronomers in observing Chariklo as it passed in front of a distant star — a process known as an occultation. As the asteroid traveled, it blocked light from the star, enabling scientists to learn more about it.

    The astronomers were surprised to discover that a few seconds before and after the main occultation, the light dimmed slightly, indicating that something circled the rocky asteroid. By comparing the data gathered from seven different telescopes, the team was able to identify the shape, size and orientation of the rings.

    The system consists of a dense, 4-mile-wide (7 km) ring near the planet, and a smaller 2-mile-wide (3 km) ring farther out.

    From the surface of the asteroid, “they would be two spectacular sharp and really bright rings, crossing all the sky,” Braga-Ribas said. “They would be noticeably close, as they are at about 1/1,000 of the moon’s distance from us,” he added.

    He went on to say that the larger, inner ring would block the view of the outer ring from the ground. The rings are similar to those around Saturn, in that both are very dense, bright and possibly formed by rock and water ice. But their scales are quite different.

    “The whole Chariklo system would fit about 12 times in the Cassini Division,” Braga-Ribas said, referring to the largest gap in Saturn’s rings.

    Particles orbiting Chariklo also travel more slowly — only tens of meters per second, compared with tens of kilometers per second in the rings of Saturn.

    While Saturn is the most well-known ringed body in the solar system, Jupiter, Neptune and Uranus also have their own, fainter rings. These gas giants significantly dwarf the smaller asteroid.

    Astronomers utilized seven telescopes, most of which were located in South America. Of them, only the European Southern Observatory’s La Silla telescope in Chile was able to capture the small gap between the rings.

    ESO LaSilla Long View
    ESO/LaSilla

    “This was possible due to the use of the ‘Lucky Imager,’ a fast and sensible camera that obtained a sequence of images like a video at a rate of 10 images per second,” Braga-Ribas said. “As the stellar occultation by both rings lasted for 0.6 seconds in total, it was able to ‘see’ the rings in detail.”

    The other telescopes had exposure times greater than 0.7 seconds, so they were only able to observe a single gap in the light.

    What’s so special about this asteroid to make it have rings?
    “Chariklo seems to be nothing special, otherwise,” Joseph Burns, of Cornell University, told Space.com by email. Burns was not a member of Braga-Ribas’ team, but he studies planetary rings and the small bodies of the solar system. He authored a perspective article that appeared alongside the new findings.

    Chariklo may not be the only nonplanetary body to have rings, Braga-Ribas said. “Rings may be a much more common property than we thought,” he said.

    The research and Burns’ accompanying article were published online today (March 26) in the journal Nature.

    Chariklo’s ‘toy ring’

    Chariklo is the largest of the centaurs, several bodies in the outer solar system whose orbits cross — and are changed by — the outer planets. The centaurs share characteristics with both asteroids and comets, and are thought to come from the Kuiper Belt region beyond Pluto. Rocky Chariklo appears to be more asteroid than comet in composition, according to the paper.

    kb
    Kuiper Belt

    This placement may help to explain the presence of Chariklo’s rings and their absence in the asteroid belt that lies between Mars and Jupiter. The rocky inner planets and the asteroid belt lie closer to the sun, and experience stronger forces from the solar wind, which can more efficiently blow small particles away from objects they might otherwise orbit, Braga-Ribas said.

    Collisions in the fast-moving asteroid belt are also violent processes due to their faster orbital speeds. Crashes between the nearby rocky bodies may wind up hurling any potential ring material away too quickly. The collision that likely created Chariklo’s rings would have had to have been a slow-moving impact. The asteroid’s small size means it has very little gravity, allowing fast-moving objects to easily escape from its orbit; the asteroid would only have been able to hold on to slower-traveling objects.

    The presence of a ring system answers questions about why the asteroid has brightened since observations in 2008. Originally viewed edge-on, the rings have become visible over the last five years as their inclination changed.

    Twice in its 29-year orbit, Saturn’s rings act the same way, appearing as a thin line to observers on Earth, Burns said. “This behavior confounded Galileo, as viewed through his crude telescope, on his discovery of Saturn’s rings,” Burns said. “It took many more observers and nearly 50 years before the rings’ nature was understood by Christiaan Huygens.”

    The age of the rings remains another mystery. Over the course of a few million years, the small pieces of a ring system should spread out. Because they are still contained as a ring, the authors concluded that either the system is very young, or the asteroid hosts a small moon that shepherds and confines the particles in their orbit. The moon would be about as massive as both rings combined, and would easily escape detection given Chariklo’s great distance.

    “Shepherds are the preferred — and basically only — explanation,” Burns said. “But Saturn’s and Uranus’ rings have many gaps where we should see shepherds and we don’t. Something is missing in our understanding. Maybe studying Chariklo’s toy rings will bring us ideas.”

    If a missing moon circles the asteroid, keeping the rings in line, then the system could have lasted since the dawn of the solar system, Braga-Ribas said, adding that the disturbance of the gas giant that moved Chariklo to its present-day orbit would require a very close pass to disturb the ring system, indicating that they could have survived the migration.

    Studying the stability of Chariklo’s rings can tell astronomers about the environment required to form and maintain them — a process that can be used to understand the dynamics of the early stages of the solar system.

    On a wider scale, the tiny ringed asteroid can also help scientists to understand more about how galaxies form.

    “The shepherd mechanism seems to be universal from the giant planets to the small minor planet,” Braga-Ribas said. “This mechanism may be acting in other kinds of debris discs, such as proto-planetary nebulae and galaxies.”

    See the full article, with other material, here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 12:07 pm on November 18, 2014 Permalink | Reply
    Tags: , , , , , space.com   

    From SPACE.com: ” Dark Matter Murder Mystery: Is Weird Substance Destroying Neutron Stars?” 

    space-dot-com logo

    SPACE.com

    November 18, 2014
    Charles Q. Choi

    dm
    This illustration shows a dark matter annihilation map. Credit: Illustris Collaboration

    The mysterious substance that makes up most of the matter in the universe may be destroying neutron stars by turning them into black holes in the center of the Milky Way, new research suggests.

    ns
    When an image from NASA’s Chandra X-ray Observatory of PSR B1509-58 — a spinning neutron star surrounded by a cloud of energetic particles –was released in 2009, it quickly gained attention because many saw a hand-like structure in the X-ray emission. In a new image of the system, X-rays from Chandra in gold are seen along with infrared data from NASA’s Wide-field Infrared Survey Explorer (WISE) telescope in red, green and blue. NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, also took a picture of the neutron star nebula in 2014, using higher-energy X-rays than Chandra. PSR B1509-58 is about 17,000 light-years from Earth.
    JPL, a division of the California Institute of Technology in Pasadena, manages the WISE mission for NASA. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for the NASA Science Mission Directorate. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations.

    If astronomers successfully detect a neutron star dying at the metaphorical hands of dark matter, such a finding could yield critical insights on the elusive properties of material, scientists added.

    Dark matter — an invisible substance thought to make up five-sixths of all matter in the universe — is currently one of the greatest mysteries in science. The consensus among researchers suggests that dark matter is composed of a new type of particle, one that interacts very weakly at best with all the known forces of the universe. As such, dark matter is invisible and nearly completely intangible, mostly detectable only via the gravitational pull it exerts.

    A number of ongoing experiments based on massive sensor arrays buried underground are attempting to identify the weak signals dark matter is expected to give off when it makes a rare encounter with other particles. In addition, the most powerful particle accelerator on Earth, the Large Hadron Collider (LHC), is attempting to create particles that might be dark matter. So far, none of these studies have confirmed any signs of dark matter, leaving much uncertain about its properties.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    Now, physicists suggest answers to the mystery of dark matter might lie in another puzzle, known as the missing pulsar problem.

    A pulsar is a kind of neutron star, which is a super-dense remnant of a massive star left behind after dying in a gigantic explosion known as a supernova. Neutron stars can devour matter from companion stars, acts of cannibalization that make neutron stars give off pulses of radiation, earning such neutron stars the name pulsar.

    According to current astrophysical and cosmological models, several hundred pulsars should be orbiting the supermassive black hole at the heart of the Milky Way. However, searches for these pulsars by looking for the radio waves they emit have so far come up empty-handed.

    Now researchers suggest dark matter could destroy these neutron stars, transforming them into black holes.

    Dark matter, like ordinary matter, is drawn to the gravity of other matter. The greatest concentration of normal matter in the Milky Way is at its center, so the greatest concentration of dark matter is there as well.

    In a region of high dark matter density such as the heart of the Milky Way, an enormous amount of dark matter particles could accumulate in a pulsar, causing it to grow massive enough to collapse and form a black hole.

    “It is possible that pulsars imploding into black holes may provide the first concrete signal of particulate dark matter,” said study co-author Joseph Bramante, a physicist at the University of Notre Dame.

    The models of dark matter that are most consistent with this idea, and with observations of pulsars seen outside the galactic center, are ones that suggest dark matter is asymmetric, meaning there is more of one kind of dark matter particle than its antiparticle counterpart. Normal matter is asymmetric as well — there are far more protons in the universe than anti-protons. (When a particle and its antimatter counterpart meet, they annihilate each other, releasing a burst of energy — a proof of Einstein’s famous equation, E=mc2, which revealed mass can be converted to energy and vice versa.)

    “For me, the most surprising result is that already existing models of dark matter could cause pulsars at the galactic center to collapse into black holes,” Bramante told Space.com.

    If dark matter is asymmetric, this would be consistent with “why there is more matter than antimatter in the universe, and why there is five times more dark matter than visible matter,” Bramante added.

    The mass of the dark matter particle responsible for imploding pulsars in the galactic core might be 100 times lighter than an electron or heavier than 100 million protons. If dark matter is as massive as 100 million protons, it would take more than 1,000 times the energies capable at the LHC to create them, Bramante noted. This suggests that looking for an imploding pulsar in the centers of galaxies might be a more feasible way to learn about dark matter.

    There might be other explanations for the missing pulsar problem. For instance, massive stars may form short-lived, highly magnetic pulsars known as magnetars in the galactic center rather than ordinary long-lived pulsars, perhaps because stars in the galactic core might be highly magnetized. The researchers are exploring how astronomers might identify whether a pulsar in the galactic core died because of dark matter, supporting their idea.

    Bramante and his colleague Tim Linden detailed their findings Oct. 10 in the journal Physical Review Letters.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 3:36 pm on November 17, 2014 Permalink | Reply
    Tags: , , , , space.com, Supercritical carbon dioxide   

    From SPACE.com: “Alien Life Could Thrive on ‘Supercritical’ CO2 Instead of Water” 

    space-dot-com logo

    SPACE.com

    November 16, 2014
    Charles Q. Choi

    Alien life might flourish on an exotic kind of carbon dioxide, researchers say. This “supercritical” carbon dioxide, which has features of both liquids and gases, could be key to extraterrestrial organisms much as water is to biology on Earth.

    Most familiar as a greenhouse gas that traps heat, helping warm the planet, carbon dioxide is exhaled by animals and used by plants in photosynthesis. While it can exist as a solid, liquid and gas, past a critical point of combined temperature and pressure, carbon dioxide can enter a “supercritical” state. Such a supercritical fluid has properties of both liquids and gases. For example, it can dissolve materials like a liquid, but flow like a gas.

    The critical point for carbon dioxide is about 88 degrees Fahrenheit (31 degrees Celsius) and about 73 times Earth’s atmospheric pressure at sea level. This is about equal in pressure to that found nearly a half-mile (0.8 kilometers) under the ocean’s surface. Supercritical carbon dioxide is increasingly used in a variety of applications, such as decaffeinating coffee beans and dry cleaning.

    Strange possibility for life

    Ordinarily, carbon dioxide is not considered a viable solvent to host the chemical reactions for life, but the properties of supercritical fluids can differ quite significantly from the regular versions of those fluids — for instance, while regular water is not acid, supercritical water is acidic. Given how substantially different supercritical carbon dioxide is from regular carbon dioxide in terms of physical and chemical properties, scientists explored whether it could be suitable for life.

    “I always have been interested in possibly exotic life and creative adaptations of organisms to extreme environments,” said study co-author Dirk Schulze-Makuch, an astrobiologist at Washington State University in Pullman. “Supercritical CO2 is often overlooked, so I felt that someone had to put together something on its biological potential.”

    The researchers noted that enzymes can be more stable in supercritical carbon dioxide than in water. In addition, supercritical carbon dioxide makes enzymes more specific about the molecules they bind to, leading to fewer unnecessary side reactions.

    Surprisingly, a number of species of bacteria are tolerant of supercritical carbon dioxide. Prior research found that several different microbial species and their enzymes are active in the fluid.

    In addition, exotic locales on Earth support the idea that life can survive in environments rich in carbon dioxide. Previous studies showed that microbes can live near pockets of liquid carbon dioxide trapped under Earth’s oceans.

    This liquid carbon dioxide in the seafloor gets denser with greater depth, as the weight of the seas and rock above it increases. As that happens, the fluid could become supercritical, and microbes might use at least some of the biologically advantageous properties of this supercritical carbon dioxide to survive, Schulze-Makuch said. Indeed, there may be many reservoirs of supercritical carbon dioxide under the oceans, he added.

    “It would be great to drill into areas with supercritical carbon dioxide on Earth and investigate those environments in detail, but this is obviously difficult because of practical limitations and huge expenses,” Schulze-Makuch said.

    ve
    Was Venus a “spuercritical” haven?

    Since carbon dioxide is a very common molecule in planetary atmospheres, the researchers suggest that supercritical carbon dioxide may be present on many worlds. This is especially true for Venus, whose atmosphere is mostly carbon dioxide.

    In its early history, Venus was located in the sun’s habitable zone, the area where liquid water can form on a planet’s surface. Life as it is currently known could have developed there before Venus heated up enough to lose all its water. Although Schulze-Makuch said it was unlikely that any such life could have switched from water to supercritical carbon dioxide, perhaps some organic remnants of such life, if it existed, could have been preserved in that fluid.

    Beyond the solar system, Schulze-Makuch noted that many newfound planets orbiting distant stars are so-called super-Earths, worlds up to 10 or more times the mass of Earth. Under the stronger gravitational pulls and correspondingly higher atmospheric pressures of those planets, supercritical carbon dioxide might be common, he said.

    k22
    Kepler 22b, a possible “super-earth

    Although Schulze-Makuch noted there is no proof that life that does not depend on water is possible, “there are good reasons to hypothesize that this is so,” he told Space.com.

    Schulze-Makuch and his colleague Ned Budisa detailed their findings in the September issue of the journal Life.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 11:48 am on November 16, 2014 Permalink | Reply
    Tags: , , , , space.com   

    From SPACE.com: “Quasars: Brightest Objects in the Universe” 

    space-dot-com logo

    SPACE.com

    August 23, 2012
    Nola Taylor Redd

    Shining so brightly that they eclipse the ancient galaxies that contain them, quasars are distant objects powered by black holes a billion times as massive as our sun. These powerful dynamos have fascinated astronomers since their discovery half a century ago.

    In the 1930s, Karl Jansky, a physicist with Bell Telephone Laboratories, discovered that the static interference on transatlantic phone lines was coming from the Milky Way. By the 1950s, astronomers were using radio telescopes to probe the heavens, and pairing their signals with visible examinations of the heavens.

    NRAO VLA
    NRAO/Karl V. Jansky Array

    qua
    This artist’s concept illustrates a quasar, or feeding black hole, similar to APM 08279+5255, where astronomers discovered huge amounts of water vapor. Gas and dust likely form a torus around the central black hole, with clouds of charged gas above and below.
    Credit: NASA/ESA

    However, some of the smaller point-source objects didn’t have a match. Astronomers called them “quasi-stellar radio sources,” or “quasars,” because the signals came from one place, like a star. Naming them didn’t help determine what these objects were. It took years of study to realize that these distant specks, which seemed to indicate stars, are created by particles accelerated at velocities approaching the speed of light.

    Light-speed jets

    Scientists now suspect that the tiny, point-like glimmers are actually signals from galactic nuclei outshining their host galaxies. Quasars live only in galaxies with supermassive black holes — black holes that contain billions of times the mass of the sun. Although light cannot escape from the black hole itself, some signals can break free around its edges. While some dust and gas fall into the black hole, other particles are accelerated away from it at near the speed of light. The particles stream away from the black hole in jets above and below it, transported by one of the most powerful particle accelerators in the universe.

    Most quasars have been found billions of light-years away. Because it takes light time to travel, studying objects in space functions much like a time machine; we see the object as it was when light left it, billions of years ago. Thus, the farther away scientists look, the farther back in time they can see. Most of the more than 2,000 known quasars existed in the early life of the galaxy. Galaxies like the Milky Way may once have hosted a quasar that has long been silent.

    Quasars emit energies of millions, billions, or even trillions of electron volts. This energy exceeds the total of the light of all the stars within a galaxy. The brightest objects in the universe, they shine anywhere from 10 to 100,000 times brighter than the Milky Way.

    Family tree

    Quasars are part of a class of objects known as active galactic nuclei (AGN). Other classes include Seyfert galaxies and blazars. All three require supermassive black holes to power them.

    Seyfert galaxies are the lowest energy AGN, putting out only about 100 kiloelectronvolts (KeV). Blazars, like their quasar cousins, put out significantly more energy.

    Many scientists think that the three types of AGNs are the same objects, but with different perspectives. While the jets of quasars seem to stream at an angle generally in the direction of Earth, blazars may point their jets directly toward the planet. Although no jets are seen in Seyfert galaxies, scientists think this may be because we view them from the side, so all of the emission is pointed away from us and thus goes undetected.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 11:27 am on November 16, 2014 Permalink | Reply
    Tags: , , , , space.com   

    From SPACE.com: "The Brightest Stars in the Sky: A Starry Countdown" 

    space-dot-com logo

    SPACE.com

    March 18, 2014
    SPACE.com Staff

    The night sky can be a wondrous place filled with stars, but there are some brilliant celestial lights that shine brighter than others.

    Astronomers measure the brightness of stars, planets and other night sky objects using a scale called magnitude. The lower the magnitude number an object has, the brighter it shines. (Objects with negative numbers are exceptionally bright.)

    Here’s a look at the brightest stars in the night (and day) sky based on their “apparent magnitude,” which is how bright they appear from Earth.

    ach
    The star Achernar lies in the constellation of Eridanus. The star has an apparent magnitude of 0.46 and an absolute magnitude of -1.3. It lies 69 light-years from Earth.

    2
    Next on the brightness list is Procyon, which is located in the constellation of Canis Minor (the lesser dog), 11.4 light-years from Earth. The star has an apparent magnitude of 0.38 and an absolute magnitude of 2.6. Image: Procyon, Betelgeuse and Sirius form the Winter Triangle.

    3
    The star Rigel lies in the constellation of Orion, 1,400 light-years from Earth. The star has an apparent magnitude of 0.12 and an absolute magnitude of -8.1. Image: Light from the star Rigel reflects off the dust composing the Witch Head Nebula

    4
    Capella lies in the constellation of Auriga, 41 light-years from Earth. The star has an apparent magnitude of 0.08 and an absolute magnitude of 0.4. Image: This sky map shows the location of Capella, a bright star also known as the “Goat Star,” in the constellation Auriga, the Charioteer.

    5
    The star Vega (of Contact fame) lies in the constellation of Lyra, 25 light-years from Earth. The star has an apparent magnitude of 0.03 and an absolute magnitude of 0.6. Image: The Milky Way shines over western Iowa, August 31, 2013. The bright star Vega stands out at top center.

    7
    The bright star Arcturus lies in the constellation of Boötes, 34 light-years from Earth. The star has an apparent magnitude of -0.04 and an absolute magnitude of 0.2. Image: A lunar halo glows over Mersing, Malaysia. Venus appears at the bottom right with Saturn near the top of the moon. The fourth brightest star in the night sky, Arcturus, is seen near the top right corner.

    8
    Rigil Kentaurus is the third brightest star in the night sky, though its brightness is due to the proximity of the system — commonly known as Alpha Centauri — which is the sun’s closest neighbor, about 4.3 light-years away from Earth. The star is located in the Centaurus constellation, and has an apparent magnitude of -0.27 and an absolute magnitude of 4.4

    9
    Canopus lies in the constellation of Carina, 74 light-years from Earth. The star has an apparent magnitude of -0.72 and an absolute magnitude of -2.5. Image: Canopus, the second-brightest star in the sky, is visible in this view photographed by astronaut Donald R. Pettit, Expedition Six NASA ISS science officer, on board the International Space Station.

    10
    Sirius lies in the constellation of Canis Major, 8.6 light-years from Earth. The star has an apparent magnitude of -1.46 and an absolute magnitude of 1.4. Image: This Hubble Space Telescope image shows Sirius A, the brightest star in our nighttime sky, along with its faint, tiny stellar companion, Sirius B.

    11
    The sun, of course, represents the closest star to us. Earth orbits 93 million miles from the sun, which has an apparent magnitude of -26.72 and an absolute magnitude of 4.2. Image: Venus transits the sun, with sunspots, on June 5, 2012.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 9:31 am on November 14, 2014 Permalink | Reply
    Tags: , , , , , space.com   

    From SPACE.com: “Could There Be Organic Matter on Mars?” 

    space-dot-com logo

    SPACE.com

    November 13, 2014
    Tanya Lewis

    The origins of organic matter found by Mars lander missions have long been debated, but a new study suggests a way to find out whether these chemicals of life came from the Red Planet or elsewhere.

    mat
    Micrometeorites are some of the most abundant material to fall on Mars, and contain organic carbon that may form chloromethane when heated.
    Credit: Bastian Baecker (University of Heidelberg and Max Planck Institute for Chemistry) and Luigi Folco (University of Pisa)

    Several Mars lander missions have detected chloromethane, a chemical sometimes produced by living organisms, but most scientists think the findings were contamination from Earth.

    Now, a team of researchers has replicated these experiments on a meteorite found on Earth, and found that it produced chloromethane from organic materials contained in the space rock. The findings suggest the chloromethane on Mars may have come from meteorite debris on the planet’s surface or the Martian soil itself, rather than from Earth.

    NASA’s Viking landers descended onto the Red Planet in 1976. The Viking 1 lander, the first of the two, detected chloromethane in a sample of soil it baked in a small oven on board. The second lander, Viking 2, did not detect chloromethane, but did find traces of dichloromethane, another organic compound. However, scientists dismissed the findings, saying they were contamination from Earth.

    NASA Viking 1
    NASA/Viking 1

    More recently, NASA’s Curiosity rover found traces of chloromethane in soil heated in one of its own chemistry instruments. Again, researchers claimed the chemicals were nothing more than terrestrial contamination, partly because it wasn’t clear whether such chemicals could form on their own.

    NASA Mars Curiosity Rover
    NASA/Mars Curiosity

    Frank Keppler, a biogeochemist at the University of Heidelberg in Germany, led a study to analyze the Murchison meteorite that landed in Australia in 1969. He reasoned that if he could understand how chloromethanes formed from this meteorite, he might be able to shed some light on whether the ones found on Mars came from Earth, from other meteorites or from the Red Planet itself — and possibly from life.

    mur
    Murchison meteorite at the The National Museum of Natural History (Washington)

    Mars is constantly pummeled by small rocks called micrometeorites. “Every year, about 50,000 tons fall on the Martian surface,” Keppler said. Most of these are carbonaceous, meaning they contain carbon, an essential building block for life.

    The researchers heated up material from the Murchison meteorite to temperatures of up to 750 degrees Fahrenheit (400 Celsius), similar to those in the Viking and Curiosity experiments, and sure enough, they found chloromethane. They knew it wasn’t contamination from Earth because it had a different chemical fingerprint.

    Chemical elements come in different forms, called isotopes. The researchers looked at the isotope signatures of carbon and nitrogen in the chloromethane from the meteorite, and they didn’t match those found on Earth. Heating up the chemicals produced similar amounts of chloromethane as those found by Viking and Curiosity, suggesting the same process may have occurred with micrometeorites on the Red Planet.

    To determine whether the chloromethane on Mars came from Earth, from meteorites or from the Martian soil, scientists could measure its isotopic signature, Keppler said. At the moment, the landers on Mars (including Curiosity) do not have the tools to measure these isotopes, but perhaps future missions will, he said.

    Based on the findings, the presence of chloromethane is a “clear sign” that organic matter exists on Mars, Keppler said. This doesn’t necessarily suggest the organic matter came from life, he said, “but we cannot exclude it.”

    See the full article here.

    Please help promote STEM in your local schools.
    STEM Icon

    Stem Education Coalition

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
Follow

Get every new post delivered to your Inbox.

Join 354 other followers

%d bloggers like this: