What seed will we look for in a distant exoplanet in the hunt for Earth-like worlds and perhaps life? A recent observation by the Hubble Space Telescope found signatures of stories from our home planet looking at a known source in extraordinary circumstances: The Earth Moon, during a total lunar eclipse.
The experiment was conducted by the Hubble Space Telescope, launched in 1990 and now in its 30th year of operation. Orbiting the Earth once every 96 minutes, Hubble usually aims to fade distant galaxies, not the bright Moon nearby. Researchers at the University of Colorado (Boulder) and the Space Telescope Institute of Science decided to do just that, during the total lunar eclipse in January 2019.
A total lunar eclipse occurs when the Moon passes in the shadow of the Earth. As fans of the eclipse know, the Moon does not completely disappear when it enters the dark inner shadow of the interior, but rather appears reddish in color. This is because of the light from thousands of suns that are being filtered into the Earth’s atmosphere, cast on the Moon. From the lunar surface looking back at the Earth, you will see a total solar eclipse. Moreover, not every total lunar eclipse looks the same. Throughout, a lunar eclipse can appear anywhere, from a pale orange to yellow, to a dark brick red. The first color depends on how deep the Moon appears in the Earth’s shadow and the amount of dust and aerosols suspended in the Earth’s atmosphere.
An ‘Exoplanet Eclipse’
The researchers realized that the reflected light of the Moon would mimic something that researchers are currently looking for: light flow through the atmosphere of a distant exoplanet as it passes in front of its host star. The current exoplanet plan stands at 4,302 and increases. Moreover, a new generation of space observers led by the James Webb Space Telescope (set to launch in October 2021) will soon be able to routinely image directly passing transplanes. Another upcoming mission, the Large Ultra Violet Optical Infrared Survey (LUVOIR), could also image exoplanets directly in ultraviolet, a key wavelength. This will create an exciting new era of exoplanet science, allowing astronomers to take in the spectrum. This, in turn, will tell us something about what constitutes the atmospheres of these exotic worlds. It can also give us hints of any interesting chemical process at work in these distant worlds.
Hubble discovered one key chemical during the eclipse: ozone. The combination of three atoms of oxygen, ozone on Earth is the result of photosynthesis during geological periods.
“The discovery of ozone is significant because it is a photochemical byproduct of molecular oxygen, which in itself is a byproduct of life,” says Allison Youngblood (Laboratory for Atmospheric Physics and Space) in a recent press release. “You would need spectral signatures other than ozone to conclude that there was life on the planets, and these signatures may not necessarily be seen in ultraviolet light.”
Although ozone is not produced exclusively by ozone life ozone can also result from nitrogen and oxygen exposed to sunlight – a seasonal fluctuation in ozone levels would be a strong bio signature. In the same way, abundant amounts of oxygen and methane – both reactive and in need of replenishment to continue for long periods of time – would be strong allusions that something interesting is happening in a distant world.
This marked the first time a space telescope has made observations of ultraviolet wavelengths during a total lunar eclipse. The discovery of terrestrial ozone, along with the first oxygen and methane in the spectra of the Earth eclipse, was supported by ground-based observations during the same January 2019 eclipse. However, terrestrial-based observers need to correct Earth, while spatial-based observations do not suffer from this barrier.
Another key we can discover in the spectrum of an exoplanet is what is known as the ‘red lip’ a signature that is solely due to plants and photosynthesis. While this would be an extraordinary discovery, it would also be stingy as primarily a graphic. Seedlings we would like really how to see is those alien jungles…
“Photosynthesis may be the most productive metabolism that can evolve on any planet because it is driven by energy from stellar rays and uses cosmically abundant elements such as water and carbon dioxide,” said Giada Arney (NASA / GSFC) in a statement. latest press release. “These necessary ingredients should be common on habitable planets.”
we’ve transmitted our bio signature across the galaxy to anyone who might be watching now for the last 2.4 billion years. Since the beginning of the Proterozoic era, when oxygen first began to build up in the Earth’s atmosphere.
However, it is brilliant to see that there is a real science that occurs during total lunar eclipses. The next chance you will get for the miracle on the green moon will be during the next total lunar eclipse, on May 26th.th, 2021. Perhaps, the science gathered by Hubble will soon begin in a new era of exoplanet science.
Read the full study here.
Credit to the main figure: An artist’s conception of Hubble glowing the Earth Moon during a total lunar eclipse. Credit: M. Kornmesser / ESA / NASA.