Earth's Infrared Secrets: The Key to Finding Life on Distant Worlds

The plan is to place five small satellites in space close to the Webb Space Telescope. Together these telescopes will act as a large telescope that will be used as an interferometer to receive infrared heat radiation from extrasolar planets. Finding life on Earth will give a good calibration of the spacecraft

Life is indeed possible on Earth. This was proven in a study conducted at ETH Zurich. The intention of the researchers was not, of course, to answer the question itself. They used Israel as an example to prove that the planned LIFE space mission (Large Interferometer for Extrasolar Planets) could succeed - and that the planned measurement procedure was working.

Using a network of five satellites, the international initiative LIFE led by ETH Zurich hopes one day to discover traces of life in extrasolar planets. The goal is to study in more detail Earth-like extrasolar planets - rocky planets similar to Earth in size and temperature but orbiting other stars.

The plan is to place five small satellites in space close to the Webb Space Telescope. Together these telescopes will act as a large telescope that will be used as an interferometer to receive infrared heat radiation from extrasolar planets. It will be possible to use the spectrum of the light to infer the composition and atmosphere of these stars. "Our goal is to identify chemical compounds in the light spectrum that suggest life in a star," explains Sasha Kvantz, who heads the LIFE initiative.

In the study, the researchers investigated to what extent a LIFE mission could characterize the habitability of an extrasolar planet. To this end, they decided to treat the Earth as an extrasolar planet and make observations of it.

What is unique about this study is that the team tested the capabilities of the future LIFE mission on real rather than simulated spectra. Using data from one of the atmospheric measuring instruments on the Aqua Earth observation satellite, they created the emission spectra of the country in the mid-infrared range, as they will be recorded in future observations of extrasolar planets.

There were two main considerations in this project. The first: If a space telescope were to observe the Earth from space, what kind of infrared spectrum would it record? The observation of the land will be from a long distance, so it will appear as an inconspicuous blob, without recognizable landforms such as the sea or mountains. This means that the spectra will be space- and time-dependent averages that will depend on which aspects of the Earth the telescope captures and for how long.

From the first consideration arose the second consideration of the physicists in their research: if they analyze these average spectra to obtain information about the Earth's atmosphere and the conditions on its surface, in what ways do the results depend on factors such as observational geometry and seasonal fluctuations?

The researchers examined three observation geometries - the two aspects from the poles and another aspect from the equator - and focused on data recorded in January and July to take into account the biggest seasonal changes.

The important findings of the study are encouraging: if a space telescope like LIFE were to observe the Earth from a distance of about 30 light years, it would find signs of a temperate world and return. The team was able to detect concentrations of atmospheric CO gases₂, water, ozone and methane in the infrared spectra of the earth's atmosphere, and also favorable conditions on the ground for water costs. The evidence for the existence of ozone and methane is especially important because these gases are created by the biosphere of the country.

These results are independent of the observational geometry, which is good news because the exact observational geometry of future observations of extrasolar Earth-like planets will likely not be known.

for the scientific article

More of the topic in Hayadan:

• NASA Announces 1,284 New Extrasolar Planets - Largest Harvest to Date
• The evolution of planets is revealed in a distant solar system
• Spitzer discovered distant galaxies that had not been seen before
• An eighth and distant ring has been discovered on Saturn
• The Webb Space Telescope Peeps Into Chaos - Captures Stellar Gymnastics in the Wheel Galaxy