The achievements of astronomy over the last four centuries are intimately linked to the development of innovative instruments. More and more telescopes are peering into the very limits of the universe in its earliest days. Overcoming those limits, however, requires powerful approaches and an old idea is now being proposed again as a revolutionary project.
A team of astronomers have put forward the idea of the Ultimately Large Telescope. As the name suggests, it would truly push the envelope of science and engineering. The telescope would have a primary mirror 100 meters (330 feet) across, larger than the largest planned telescope in the works. To achieve such a size, the mirror would be made of a reflective liquid that's constantly spinning to achieve the correct parabolic shape.
If all this is not enough, the team propose building it on the Moon. Without the effects of Earth’s atmosphere, the telescope would reach a clarity without equal.
The idea was first proposed in 2008 by a team led by Roger Angel at The University of Arizona, a proposal they referred to as the Lunar Liquid-Mirror Telescope (LLMT). In a paper published in The Astrophysical Journal, Anna Schauer and her team have produced new calculations on the power of such an instrument. They think it would allow astronomers to achieve a goal impossible in the near future: to observe the very first stars in the Universe.
“Throughout the history of astronomy, telescopes have become more powerful, allowing us to probe sources from successively earlier cosmic times — ever closer to the Big Bang,” team member Professor Volker Bromm, a theorist who has studied the first stars for decades, said in a statement. “The upcoming James Webb Space Telescope [JWST] will reach the time when galaxies first formed.
"But theory predicts that there was an even earlier time, when galaxies did not yet exist, but where individual stars first formed — the elusive Population III stars. This moment of ‘very first light’ is beyond the capabilities even of the powerful JWST, and instead needs an ‘ultimate’ telescope.”
The telescope would be placed in a crater near the South Pole of the Moon. It would be stationary, always studying the same patch of sky but collecting enough light to pierce the obscurity of the Cosmic Dark Ages and collect the (now) dim light of these distant stars from over 13 billion years ago.
