Science Spacebound

Very Large Telescope to get new sunglasses to spy on Alpha Centauri

The Breakthrough Initiatives program will fund an upgrade to Chile's Very Large Telescope to help it study a recently identified exoplanet in the Alpha Centauri system. 

The planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to our solar system, as seen in this artist's impression.
M. Kornmesser/ESO/Reuters
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Caption

Interstellar space: the final frontier. An upgrade to Chile’s Very Large Telescope could pave the way for a fleet of mini-probes to boldly go where no probe has gone before.

The European Southern Observatory (ESO) has announced an agreement with the billionaire-backed Breakthrough Initiatives program to fund an upgrade to the Very Large Telescope (VLT) facility in Chile. In return, the telescope will train its sharper eyes on the recently discovered Proxima b, a rocky exoplanet of our nearest star system that may serve as a potential target for future probes.

Detecting dim planets next to bright stars has been likened to finding a firefly next to a lighthouse, so astronomers have to resort to all sorts of convoluted tricks. The VLT’s specialty is seeing in the dark.

The VISIR (VLT Imager and Spectrometer for mid-Infrared) instrument collects a kind of radiation given off by heat, invisible to the naked eye. Just as infrared goggles allow soldiers to see warm objects at night, VISIR lets the VLT see hot stars and warm planets against the coldness of space.

Looking at star systems in the infrared spectrum “greatly reduces the brightness gap” between planets and stars, but planets are still quite a bit cooler than their hosts, which remain millions of times brighter. As it stands now, despite being able to theoretically detect car headlights as far away as the moon, the VLT is not quite up to the challenge. Breakthrough thinks the answer is a new pair of sunglasses.

This technology, more properly called coronagraphy, is the practice of physically blocking out the lighthouse so the fireflies will stand out. Traditionally applied to the sun to aid observation of the corona, the sun’s outer atmosphere, astronomers have only recently started to apply the technique to attempt direct photography of exoplanets.

Under the terms of the agreement, Breakthrough Initiatives will pay for most of the upgrades, including adaptive optics to counter distortions of light passing through Earth’s atmosphere, and the ESO will provide telescope time to observe Alpha Centauri. The University of Liège (Belgium) and Uppsala University (Sweden) will work together to develop a new coronagraph.

Founded by Russian venture capitalist Yuri Milner, the Breakthrough Initiatives project is an attempt to answer the question, are we alone in the universe? Mr. Milner appeared with Stephen Hawking and Mark Zuckerberg last April to announce a bold plan to send a fleet of wafer-mounted cameras to Alpha Centauri within a human lifetime. “We came to the conclusion it can be done: interstellar travel,” Milner told The New York Times.

Dragged behind laser-propelled “light-sails,” the theoretical spacecraft would make the one-way trip in about two decades, traveling at the blistering rate of one-fifth the speed of light.

Numerous hurdles stand between Milner and his dream of an Alpha Centauri close-up. In addition to the technological challenges of shrinking the spaceship weight down to a few grams and building a field of lasers capable of focusing immense power on a tiny target, a paper released in August raised the problem of interstellar dust, which the Harvard team concluded “can produce numerous craters on the spacecraft surface as a result of explosive evaporation following each dust grain encounter.”

But not to worry, Hubble is teaming up with the Voyager spacecraft to better understand the space between stars. Still flying away from Earth at 38,000 miles per hour, the now-40-year-old spacecraft will provide the micro, while Hubble watches from afar to supply the macro. Combining the two sources of data could be the beginnings of an interstellar roadmap of sorts.

"It's important for us to be aware of what kinds of objects are present beyond our solar system, since we are now beginning to think about potential interstellar space missions, such as Breakthrough Starshot," study lead author Julia Zachary told Space.com.

As for what Breakthrough Starshot might find there, the prospects are even better than when Milner announced the project. The ESO partnered with observatories around the world last summer to announce the discovery of Proxima b, a roughly Earth-sized rocky planet orbiting one of the Centauri system’s three stars. Moreover, Proxima b appears to well within the habitable zone around the star, which means it has an estimated surface temperature that would allow the presence of liquid water.

Using its upgraded capabilities, the ESO hopes to collect valuable data about the planet, although it doesn't necessarily expect a smoking gun with regards to life. “The detection of a planet by direct imaging allows us to measure colors through subsequent observations and estimate basic planet properties like temperature and size. This information could indicate habitability, although the detection of biomarkers will have to wait for the next generation,” ESO Instrument Operation Team project manager Markus Kasper tells The Christian Science Monitor in an email.

That next generation may come as soon as 2024, when the ESO hopes the European Extremely Large Telescope (E-ELT), currently under construction, will start collecting its first light.

Until then, Dr. Kasper is grateful for Breakthrough’s support: “Only the Breakthrough Initiatives made the experiment possible, because government funding agencies normally shy away from the considerable risk of a null result.”

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