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  • richardmitnick 3:19 pm on July 27, 2017 Permalink | Reply
    Tags: Alpha Centauri, , , , , , , Piggybacking on a couple of German satellites six Sprites reached low Earth orbit about 600 kilometres high on June 23.,   

    From Motherboard: “To Get to An Alien Star, Scientists Launched the Tiniest Spacecraft Ever” 



    Jul 27 2017
    Jacob Dubé

    Image: Zachary Manchester, Nasa on the Commons/Flickr. Photoshop: Jacob Dubé

    Breakthrough Starshot wants to go to Alpha Centauri.

    Breakthrough Starshot, the brainchild of everyone’s favourite physicist Stephen Hawking and Russian billionaire Yuri Milner, has the goal of getting humanity to the nearest star system, Alpha Centauri, which is 4.37 light years away. Hawking and Milner have proposed doing this with an array of tiny “nanocrafts,” and now, the mission has successfully launched the world’s smallest spacecraft into orbit around Earth.

    The crafts, named “Sprites,” are 3.5-by-3.5 centimetre chips, built on a single circuit board—each one is just shy of the size of an Oreo, yet contains computers, sensors, solar panels, and radios. Piggybacking on a couple of German satellites, six Sprites reached low Earth orbit, about 600 kilometres high, on June 23. Two Sprites are currently attached to satellites, and four are in a deployer attached to one of the satellites to be released later.

    Zac Manchester, consultant for Breakthrough Starshot who created the concept of the Sprites and Kickstarted them in 2011, raising over $74,000, told Motherboard that this is the first time his team has been able to make a real demonstration of the crafts in space and communicate with them from the ground.

    The Sprites, which weigh about four grams each and cost only $25 to make, have basic sensors like magnetometers and gyroscopes, but Manchester hopes to upgrade them with actuators for mobility, as well as more advanced sensors like chemical detectors that would allow them to explore alien environments.

    Manchester said that their low cost would allow astronauts to take more risks and send them places they wouldn’t usually go: You can picture astronauts in orbit around an alien (and possibly hostile) planet, sending a fleet of Sprites down to take some readings.

    “If you want to get up-close and even sample things, you wouldn’t want to do that with your billion-dollar satellite,” Manchester said. “But you can imagine deploying a whole bunch of these little Sprite spacecrafts and sample directly.” Because they’re cheap and unmanned, he added, “you wouldn’t care if a whole bunch of them were destroyed in the process.”

    Manchester said that, in the future, several Sprites could be networked together and function as a swarm; each with its own sensors, performing different tasks and sharing information. Since it would take the Space Shuttle some 165,000 years to get to Alpha Centauri with humans inside, sending a fleet of tiny nanobots sounds like a pretty good idea.

    See the full article here .

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    The future is wonderful, the future is terrifying. We should know, we live there. Whether on the ground or on the web, Motherboard travels the world to uncover the tech and science stories that define what’s coming next for this quickly-evolving planet of ours.

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  • richardmitnick 9:01 am on August 29, 2016 Permalink | Reply
    Tags: Alpha Centauri, , , ,   

    From SciNews: “Hubble Space Telescope Snaps Image of Alpha Centauri AB” 

    SciNews bloc


    Aug 29, 2016
    Enrico de Lazaro

    The Hubble Space Telescope team has released an incredible new image of the binary star Alpha Centauri AB.

    This Hubble WFPC2 image shows Alpha Centauri A (left) and Alpha Centauri B (right). Image credit: NASA / ESA / Hubble.

    Alpha Centauri, the closest stellar system to Earth, is located in the constellation of Centaurus.

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker
    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    Also known as Rigil Kentaurus, Rigil Kent and Gliese 559, this triple system is made up of the bright binary star formed by Alpha Centauri A and Alpha Centauri B, plus the faint red dwarf star Alpha Centauri C.

    The two brighter components are roughly 4.35 light years away from us. Alpha Centauri C, better known as Proxima Centauri, is slightly closer at 4.23 light years.

    Compared to the Sun, Alpha Centauri A is of the same stellar type G2, and slightly bigger (1.1 times more massive than the Sun and about 1.5 times more luminous).

    Alpha Centauri B, a K1-type star, is slightly smaller and less bright (0.9 times the mass of the Sun and about 45% of its visual luminosity).

    Alpha Centauri A and B orbit a common center of gravity once every 80 years, with a minimum distance of about 11 times the distance between the Earth and the Sun.

    Because these two stars are, together with Proxima Centauri, our nearest interstellar neighbors, they are among the best studied by astronomers.

    And they are also among the prime targets in the hunt for potentially habitable planets.

    Using the HARPS instrument on the 3.6-m telescope at ESO’s La Silla Observatory, Chile, astronomers already discovered a planet orbiting Alpha Centauri B. The planet, designated Alpha Centauri Bb, has a mass of a little more than that of the Earth and orbits its host star once every 3.2 days.

    Earlier this month, astronomers announced the discovery of an Earth-mass planet in the habitable zone orbiting Proxima Centauri. Named Proxima b, the planet orbits its star every 11 days and has a temperature suitable for liquid water to exist on its surface.

    This image of Alpha Centauri AB is a composite of separate exposures acquired by Hubble’s Wide Field and Planetary Camera 2 (WFPC2).

    It is based on data obtained through two filters: F457W and F850W.

    The color results from assigning different hues to each monochromatic image associated with an individual filter.

    See the full article here .

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  • richardmitnick 10:42 am on August 6, 2015 Permalink | Reply
    Tags: Alpha Centauri, , ,   

    From Institute for Astronomy U Hawaii: “Is there life in the Alpha Centauri system?” 

    U Hawaii

    University of Hawaii

    Institute for Astronomy

    U Hawaii Institute for Astonomy Mauna Kea
    IFA at Manua Kea

    Aug 6, 2015
    No Writer Credit

    Scientists propose a sensitive technique for detecting photosynthetic organisms in extrasolar planetary systems

    The search for life on other planets is fascinating, challenging, and enlightening. If successful, it will teach us about ourselves, where we come from, and what our destiny is. Scientists from the University of Hawaii, including Jeff Kuhn, David Harrington, and John Messersmith, are part of a team headed by Prof. Dr. Svetlana Berdyugina (Kiepenheuer Institut fuer Sonnenphysik and the University of Freiburg, Germany, and a visiting scientist at the University of Hawaii NASA Astrobiology Institute) that has developed a new approach to searching for life on other planets. Biologist Tina Šantl-Temkiv of Aarhus University, Denmark, is also a team member.

    Photosynthetic biopigments

    The team has measured various biological photosynthetic pigments in the laboratory. They absorb almost all solar light of specific colors in the visible and convert it into chemical bonds to store energy. For example, chlorophyll pigments absorb blue to red light and reflect a small part of green in the visible, as seen in green plants. (Figure 1).

    All infrared light is reflected, and this is employed in agriculture to monitor water content in crops. Such biopigments are contained in plants, algae, bacteria, and even in human skin (carotenoids) and eyes (rhodopsin), creating the colored beauty of our world. They can also help find life on the surfaces of other planets.

    Figure 1: A green leaf absorbs almost all red, green and blue light (RGB), but it reflects and transmits infrared light (shown in grey). The reflected infrared light is only weakly polarized due to the reflection of a healthy leaf, but the reflected RGB light is strongly polarized due to biopigments. Measuring the amount of polarized light at different colors reveals the signature of the leaf biopigments. Green sand reflects and polarizes sunlight almost equally in all wavelengths, which distinguishes it from a leaf that is a similar color. Similarly, yellow plants are different from yellow sand, etc. (Credit: S. Berdyugina)

    The scientists have found that the part of visible light reflected by various plants with vibrant colors oscillates in certain directions, while incident light oscillates in all directions (Figure 1). Thanks to this peculiarity, this reflected light can be detected remotely by using polarizing filters (similar to Polaroid sunglasses or 3D movie goggles) when viewed at specific angles even if the star is millions of times brighter than the planet. The team found that each biopigment has its own colored footprint in such polarized light.

    Modeled spectra reflected off distant exo-Earth surfaces have demonstrated the advantage of using polarized light to distinguish photosynthetic biosignatures from minerals, ocean water and the atmosphere. The high contrast of the biosignatures in the polarized light is the key to finding them in the overwhelmingly bright stellar light that usually hides the exoplanetary signals.

    These results will be published by the International Journal of Astrobiology, Cambridge University Press [1]. Earlier Prof. Berdyugina and her team employed polarized light to see for the first time the blue color of an exoplanet [2]. Now this method can help to see colors of life on other planets, even at large distances from the sun.

    Our neighbor, the triple stellar system Alpha Centauri

    This technique could be instrumental in searching for life in the planetary system nearest to the sun, Alpha Centauri, with existing telescopes. There are three stars in this system. While scientists are interested in finding life around all these stars, Alpha Centauri B, only 4.37 light years from Earth, seems optimal for life searches with current telescopes (Figure 2).

    The position of Alpha Centauri A and Alpha Centauri B

    Figure 2: The Alpha Centauri A and B stars with their habitable zones (green ovals) as seen projected on the sky. The habitable zones appear as an ovals because the planets’ orbits are inclined to our line of sight. For the same reason, the distance between the A and B stars appears shortened. If there are planets in the habitable zones (blue dots), photosynthetic biopigments could be detected with the proposed polarimetric technique. Sizes of the stars and planets are not to scale. (1 AU = the distance between Earth and the sun.) (Credit: S. Berdyugina)

    In 2014, a small planet was discovered around Alpha Centauri B. Unfortunately, this exoplanet is ten times closer to the star than Mercury is to the sun, so its surface is melting under the stellar heat, and it probably has no atmosphere. At a distance where planets like Earth with liquid water on their surface could exist (the “habitable zone”), no planets have been found as yet, but scientists are continuing to search for one. If such a planet is found, or even before that, it is possible to search for photosynthetic biosignatures in the Alpha Centauri B spectrum. Using the proposed polarization technique, this task becomes even more feasible.

    Figure 3: Artist’s impressions of Earth-like planets covered by photosynthetic organisms with terrestrial-like biopigments studied by the team. (Credit: S. Berdyugina & C. Giebink).

    This research was supported at KIS/Freiburg by the European Research Council (ERC) Advanced Grant HotMol (http://hotmol.eu), the Leibniz Association (WGL) grant InnoPol, and the UH NASA Astrobiology Institute team.


    [1] Berdyugina, S.V., Kuhn, J.R., Harrington, D.M., Šantl-Temkiv, T., Messersmith, E.J.: Remote Sensing of Life: Polarimetric Signatures of Photosynthetic Pigments as Sensitive Biomarkers, International Journal of Astrobiology</em>, in press (2015)

    [2] Berdyugina, S.V., Berdyugin, A.V., Fluri D.M., Piirola V.: Polarized reflected light from the exoplanet HD189733b: First multicolor observations and confirmation of detection, Astrophysical Journal Letters, 728, L6-L10 (2011)

    [3] Kuhn, J.R., Berdyugina, S.V.: Global warming as a detectable thermodynamic marker of Earth-like extrasolar civilizations: the case for a telescope like Colossus, International Journal of Astrobiology, vol. 14, pp. 401-410 (2015)

    See the full article here.

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