As NASA races to complete the Hubble space telescope’s successor before the 2020 deadline, one thing is clear: the space race has caught a second wind, fueled largely by technological progress. But telescope innovation is also happening on the ground at the European Southern Observatory (ESO), where a new terrestrial telescope is slated to go online by 2024.
The European Southern Observatory, situated in the Atacama desert, Chili, boasts three different research sites, each a showcase of cutting-edge telescope technology.
Chief among these, the VLT (Very Large Telescope) was implemented in 1998 to scrutinize our starry sky in search of the most exotic celestial bodies. A couple of weeks ago, it captured pictures of a protoplanet, situated more than 370 light years away from the Earth — a first in history.
The protoplanet orbits a star called PDS 70, a dwarf born about 6 million of years ago. In its orbit, a gas planet called PDS 70 b, was unexpectedly captured by during its creation. The newborn is several times larger than Jupiter and boasts a balmy surface temperature of about 1000°C (1832°F).
This is the first time astronomers have been able to photograph an emerging planet, still immersed in its placenta-like disk of cosmic gas and dust.
And it’s about to get better, as the Very Large Telescope will soon enough be made obsolete by an even more performant technology: the Extremely Large Telescope.
The ELT : the future of telescopes
The Extremely Large Telescope (ELT), is a brand new terrestrial telescope project scheduled for 2024. It will be erected near the current VLT site, which offers an exceptional vantage point for its two technological innovations: segmented mirrors and adaptive optics.
Contrary to previous generations of terrestrial telescopes, the main mirror is not composed of a single piece, but of 798 hexagonal segments, each polished to within nanometer tolerances. Previous reflective telescopes used single, monolithic mirrors, but current manufacturing processes limit their size to about 8 meters in diameter. By carefully composing each of the uniquely-shaped segments into a circular array, the ELT’s main reflective surface weighs in at an incredible 39 meters. This design should allow the telescope to “collect fifteen times more light than the most powerful optical telescopes existing nowadays”, according to the ESO.
The telescope will also feature an adaptive optics system, which compensates the effects of atmospheric distortion (due to meteorological phenomena such as variations in atmospheric temperature) to eliminate air distortions in real-time. The adaptive system is composed of four supplementary 4.2-meter mirrors, which move hundreds times per second to produce effects analogous to noise-cancelling headphones.
Air fluctuations are recorded thanks to simulated “guide stars”, thanks to laser beams coming out of the telescope. The impulsions “excite the atmospheric sodium layer’s atoms” and force them to release a yellow-coloured flash, allowing the adaptive optics system to continually adjust to atmospheric changes.
The “biggest optic and infrared telescope” will probably bring numerous contributions to astronomical research, particularly in the search for dark matter. And as always, each new generation of telescope brings with it a slight chance to find the holy grail: extraterrestrial life.
Credits : eso.org