from the that's-a-tiny-spaceship dept.
The spacecraft would be miniaturised to the size of an average silicon chip, and be propelled by a solar sail which would receive a boost from a powerful laser on the Earth.
Milner's Breakthrough Foundation is running a project, backed by Hawking, to research the technologies needed for such a mission, which they think will soon be feasible.
The Breakthrough Starshot initiative, which is known for its long-term plan for sending chip-sized craft to Alpha Centauri using lasers, will fund an upgrade to the Very Large Telescope in order to search for exoplanets:
Today, the European Southern Observatory announced an agreement with Breakthrough Starshot, A group dedicated to sending hardware to return data from the nearest stars. The agreement would see Breakthrough Starshot fund the development of new hardware that would allow the ESO's Very Large Telescope to become an efficient planet hunter. The goal is presumably to confirm there's something in the Alpha Centauri system worth sending spacecraft to image.
[...] The new hardware will be a modification of existing equipment. The Very Large Telescope is actually four eight-meter telescopes capable of being operated as a single unit. One of these (Unit 3, named "Melipal") has hardware called VISIR, for VLT Imager and Spectrometer for mid-Infrared. VISIR can separate infrared light into its component wavelengths, which can tell us something about either the source of the light or any objects in between that absorb light of these wavelengths. Exoplanets turn out to be best to image in the infrared since they often glow with heat, either left over from their formation or due to absorbing light from their host star. But VISIR isn't specialized for planet hunting. For that, it will need a coronagraph, which will blot out the light from the star and make planets easier to spot. VISIR will also need adaptive optics, which can compensate for distortions created by the atmosphere. (The Very Large Telescope may be 2.5km above sea level in a desert, but the atmosphere still poses problems.) And it will likely need additional vibration dampening equipment.
Researchers have written about some of the challenges involved in building a light sail suitable for Breakthrough Starshot, a project that would accelerate a gram-scale "chipcraft" using lasers so that it could travel interstellar distances in just decades:
A team of researchers at the California Institute of Technology has taken a hard look at the challenges facing efforts to carry out the Breakthrough Starshot project. In their Perspective piece published in the journal Nature Materials, the researchers outline the obstacles still facing project engineers and possible solutions.
The light sail would need to be made of a lightweight but reflective material able to withstand being bombarded by gigawatts of photons without melting. Graphene doesn't qualify. Many of the materials the researchers evaluated have only been studied in their bulk forms, rather than thin films, which can have different properties.
The Starshot Breakthrough Initiative established in 2016 sets an audacious goal of sending a spacecraft beyond our Solar System to a neighbouring star within the next half-century. Its vision for an ultralight spacecraft that can be accelerated by laser radiation pressure from an Earth-based source to ~20% of the speed of light demands the use of materials with extreme properties. Here we examine stringent criteria for the lightsail design and discuss fundamental materials challenges. We predict that major research advances in photonic design and materials science will enable us to define the pathways needed to realize laser-driven lightsails.
Also at Ars Technica.
Astronomers have reportedly discovered an Earth-like exoplanet in the habitable zone of Proxima Centauri, one of the closest stars to our Sun. However, the claim is based on an anonymous source who is said to have leaked the news ahead of an announcement by the European Southern Observatory:
[In] what may prove to be the most exciting find to date, the German weekly Der Spiegel [translation] announced recently that astronomers have discovered an Earth-like planet orbiting Proxima Centauri, just 4.25 light-years away. Yes, in what is an apparent trifecta, this newly-discovered exoplanet is Earth-like, orbits within it's sun's habitable zone, and is within our reach. But is this too good to be true? [...] Citing anonymous sources, the magazine stated:
The still nameless planet is believed to be Earth-like and orbits at a distance to Proxima Centauri that could allow it to have liquid water on its surface — an important requirement for the emergence of life. Never before have scientists discovered a second Earth that is so close by.
In addition, they claim that the discovery was made by the European Southern Observatory (ESO) using the La Silla Observatory's reflecting telescope. Coincidentally, it was this same observatory that announced the discovery of Alpha Centauri Bb back in 2012, which was also declared to be "the closest exoplanet to Earth". Unfortunately, subsequent analysis cast doubt on its existence, claiming it was a spurious artifact of the data analysis.
However, according to Der Spiegel's unnamed source – whom they claim was involved with the La Silla team that made the find – this latest discovery is the real deal, and was the result of intensive work. "Finding small celestial bodies is a lot of hard work," the source was quoted as saying. "We were moving at the technically feasible limit of measurement." The article goes on to state that the European Southern Observatory (ESO) will be announcing the finding at the end of August. But according to numerous sources, in response to a request for comment by AFP, ESO spokesman Richard Hook refused to confirm or deny the discovery of an exoplanet around Proxima Centauri.