Written by Dandu Lahiri, CNN
The Hubble Space Telescope is reminding us what its successor, the James Webb Space Telescope, will miss — and this time, we’re talking about the most distant exoplanets ever.
Set to launch in 2020, the James Webb will have the capabilities to look even further back in time than Hubble was designed to look. Hubble was launched in 1990 and tasked with gathering light from back when the Universe was a bit more turbulent and Earth’s atmosphere was much less protected, sending the light back through time.
Why does this matter? Because living things like humans aren’t designed to look like our universe. We’re not meant to see so far into the past. Back on Oct. 16, 2018, Hubble spotted a planet as far away as 40 million light years from Earth, and gave us our first glimpse at a planet that has a density of 8% of ours.
Galaxy 200 million light years away
The light from these distant planets passed in front of their host stars in exactly the same way as stars back in the 1970s would have done, Hubble’s principal investigator Alan Boss said in a video. “This is the earliest evidence of what the young universe looked like.”
Hubble first discovered exoplanets (that is, planets outside our solar system) in 1995. Since then, they’ve been discovered throughout the galaxy, far from starlight that can reveal their structures and atmospheres.
It’s not uncommon for scientists to catch glimpse of a planet with a huge gulf between its surface and its atmosphere. The gravity of its parent star pulls on the atmosphere like a strong blanket and throws it out over a great distance — at some point — within the reach of Hubble.
Now, for the first time ever, scientists have been able to study that process at such great detail.
“Over the course of our lifetime, we may have witnessed not only the birth of our solar system, but also the generation of some of the most massive worlds in the universe,” Caltech planetary astronomer Scott Sheppard said in a statement.
“We are getting a closer look at a handful of these worlds than ever before, and are learning more about the chemistry that may have fueled their early growth. Our findings provide new details of the solar system’s early development, and the very beginnings of the universe.”
Of course, getting closer is nothing new — astronomers first spotted worlds that were more distant than our Moon in 1965. The Kepler mission, which launched in 2009, continues to prove that astronomers can chart the orbits of millions of stars in our galaxy, and is exploring the possibility of finding planetary systems with an Earth-sized planet orbiting another star.