Hardware tuneup to prime Very Large Telescope for Alpha Centauri exploration
With loads of cash and access to some of the world's premier space observatories, the Breakthrough Initiatives program plans to examine up to a million stars in its search for extraterrestrial life. But no distant worlds appear as tantalizing at this early stage as those of the Alpha Centauri system, the closest stellar system to Earth and home to a recently discovered Earth-sized exoplanet. As part of its push to probe its secrets, the program will fund a hardware upgrade for the Very Large Telescope in Chile, equipping it with new imaging capabilities to better hunt for other habitable planets in the region.
The Alpha Centuari system might be the closest to Earth, but it is still a mighty journey, some 25 trillion miles (4.37 light years) away. That's around 30,000 years of travel time on today's fastest spacecraft. The Breakthrough Initiatives venture, backed by the likes of Stephen Hawking and Mark Zuckerberg, announced a $100 million program to develop an ultralight "nanocraft" that would travel at 20 percent the speed of light to arrive at Alpha Centauri within 20 years of launch, though years of technological research are needed first.
In the meantime, the team plans to use tools on the ground to explore Alpha Centauri's contents, though these too are in need of some cutting-edge upgrades. One of the main difficulties in hunting for habitable planets is the blinding light of the parent star that drowns out the comparably fainter body. Scientists using NASA's Kepler Telescope have had great success spotting exoplanets by looking for dips in light as the orbiting planet passes in front of its star, but it is impossible to directly photograph the planet using this technique.
Announced back in October, the Project Blue initiative aims to overcome this by building a telescope optimized to suppress the starlight in the Alpha Centauri system in just the right way so it can directly photograph its habitable planets. Among the necessary technologies are advanced post-processing techniques and an instrument called a coronagraph.
Coronagraphs are designed to block out light coming from a sun's surface and have been under development for use in space missions since the 1990's. But the Project Blue team told us last year that the technology has now matured enough to achieve the contrast and stability required to directly image exoplanets around nearby stars, and it seems the Breakthrough Initiatives program shares a similar view.
It will fund a "large fraction" of the necessary technologies and development costs to enhance the Very Large Telescope's image quality through upgrades to its adaptive optical capabilities. Adaptive optical systems emerged in the 1990's as a way of correcting distortion in telescope images caused by atmospheric turbulence, using something called a wavefront sensor to detect changes in light coming from the source (in this case the star) and then altering the imaging optics to cancel those changes out.
The Very Large Telescope's "Imager and Spectrometer for mid-Infrared" instrument will receive a new wavefront sensor and a new coronagraph, along with a new device to calibrate its detector, which plays the important role of determining things like the direction, brightness and intensity of the collected light. All going to plan, the upgrades will be completed in time for a "careful search program" in 2019.
Source: European Southern Observatory