{"id":56569,"date":"2024-03-28T08:53:30","date_gmt":"2024-03-28T08:53:30","guid":{"rendered":"http:\/\/70dca183-27a1-488a-81eb-77f13b96bdf8"},"modified":"2024-03-28T09:08:24","modified_gmt":"2024-03-28T09:08:24","slug":"life-imbalances-earths-atmosphere-now-scientists-are-using-this-knowledge-to-search-for-alien-life","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/life-imbalances-earths-atmosphere-now-scientists-are-using-this-knowledge-to-search-for-alien-life\/","title":{"rendered":"Life imbalances Earth’s atmosphere. Now scientists are using this knowledge to search for alien life"},"content":{"rendered":"

<\/p>

By Ezzy Pearson\n <\/p>

Published: Thursday, 28 March 2024 at 08:53 AM<\/p>

\n\n

Since the first exoplanets were discovered in the mid ’90s, the field of hunting for planets beyond our Solar System has exploded.<\/p>

It seems like every week now, there’s a new discovery, be that of super Earths and mini Neptunes<\/a>, or hot Jupiters<\/a> orbiting scorchingly close to their host stars.<\/p>

The field of exoplanet<\/a> study also concerns the field of search for life beyond Earth.<\/p>

Studying exoplanets’ atmospheres can tell us a lot about what that planet might be like, including whether it hosts life.<\/p>

Gases – or biosignatures – can reveal whether there is life on an exoplanet. Credit: Darryl Fonseka\/iStock\/Getty Images<\/figcaption><\/figure>
Certain chemicals in an exoplanet’s atmosphere would indicate the presence of life<\/a> on its surface: these are known as biosignatures<\/a>.<\/p>
We know that life on Earth creates waste gases that unbalance our atmosphere. Now astronomers are seeking similarly off-kilter worlds in the hunt for alien life.<\/p>
Jayne Birkby is an associate professor of exoplanetary science at the University of Oxford.<\/p>
We spoke to her to find out more about her research into searching for life in the atmospheres of planets orbiting stars beyond our Sun.<\/p>
$\"jayne$ <\/figure>
How do you use exoplanet atmospheres to look for life?<\/strong><\/h2>
Life impacts our atmosphere on Earth. The amount of oxygen in our atmosphere is in a disequilibrium state; there\u2019s something constantly replenishing it in our atmosphere \u2013 and that\u2019s life.<\/p>
If all life on Earth was to suddenly disappear, the oxygen in our atmosphere would disappear.<\/p>
The idea is that if we can see the same signature of disequilibrium elsewhere, that starts to become a signature that maybe life is causing that.<\/p>
What molecules are you looking for?<\/strong><\/h2>
There are four main molecules that we focus on when talking about Earth-like life: oxygen, water, carbon dioxide and methane.<\/p>
There are other less abundant things out there that might signal life as well, molecules that can only be made by life.<\/p>
But the former are the easiest things for us to look for.<\/p>
It\u2019s the abundance that matters \u2013 on Earth, we have 21% oxygen.<\/p>
The molecule itself also makes it easier to observe, as it has a strong absorption line in its spectrum, which makes it easier to detect.\u00a0<\/p>
$\"The$
The radial velocity method of exoplanet detection looks for a shift in the spectrum of star light as a star wobbles due to the gravitational pull of an exoplanet in orbit around it. Credit: ESA<\/figcaption><\/figure>
How do you observe exoplanet atmospheres?<\/strong><\/h2>
As a planet orbits, it causes its star to wobble back and forth because of the gravitational pull of that star.<\/p>
The star is wobbling at a few centimetres or metres per second. Meanwhile, the planet is whizzing around at kilometres per second.<\/p>
That means if you were to observe the spectra of the planet you would see it Doppler-shifting back and forth, while the star by comparison would look almost stationary.<\/p>
Remove everything that isn\u2019t moving in wavelength over time and what you\u2019re left with \u2013 buried in a lot of noise \u2013 is a spectrum.<\/p>
If we do this at a high resolution, there are many lines, so it\u2019s a very robust detection.<\/p>
What kind of planets do you observe?<\/strong><\/h2>
The important thing about this technique is that it works on non-transiting exoplanets. That meansit makes the nearest planets accessible.<\/p>
With our current facilities, telescopes in the eight-to-10-metre class, we\u2019re looking in detail at hot Jupiters.<\/p>
We\u2019re starting to push towards the mini-Neptunes \u2013 we really don\u2019t know much about these planets at all.<\/p>
About 75 planets have been observed at high spectral resolution, finding molecules and atomic species in the atmospheres.<\/p>
For the very specific method of high resolution with cross correlation that I do, the number is more like 50\u201360 planets.<\/p>
$\"Most$
Most of the new exoplanets found so far are in between Earth and Neptune in size, so-called super-Earths and mini-Neptunes. Credit: NASA\/ESA\/CSA and STScI<\/figcaption><\/figure>
How common are the molecules that you\u2019re looking for?<\/strong><\/h2>
We see water pretty much everywhere. We find carbon monoxide in a lot of hot Jupiters too.<\/p>
This is all expected from standard equilibrium chemistry.<\/p>
Carbon dioxide has only been confidently seen with low-resolution spectra from space.<\/p>
Methane is tentatively seen using the high-resolution method in hot Jupiters, but has been seen at lower resolution with the James Webb Space Telescope for a sub-Neptune planet.<\/p>
Oxygen has not been detected. None of these suggests any evidence of life.<\/p>
That would be more for the rocky planets, which we haven\u2019t looked at yet at high resolution.\u00a0<\/p>
$\"Artist's$
Artist’s impression of the European Extremely Large Telescope in operation. Credit: ESO\/L. Cal\u00e7ada<\/figcaption><\/figure>
How could you examine rocky worlds?<\/strong><\/h2>
We need the Extremely Large Telescope, due to start operations in 2028. It will have a 39-metre-diameter mirror \u2013 we need that big \u2018light bucket\u2019.<\/p>
The goal is to make a census of rocky planets and see how many of them are like Earth.<\/p>
Maybe they\u2019re all like Venus \u2013 really hot, with a sulphuric atmosphere that\u2019s inhospitable to life.<\/p>
Or maybe they\u2019re like Mars, just arid deserts.\u00a0<\/p>
Water and methane, in particular, have quite complex spectra that make them harder to distinguish, so the fact that we can find molecules in hot gas giant planets is good news for searching for biosignatures on rocky worlds.<\/p>
It means when we look at rocky planets where we might hope to find life and where these molecules could be biosignatures, we know that our methods will work.<\/p>
***This interview appeared in the April 2024 issue of BBC Sky at Night Magazine<\/em><\/strong><\/p> <\/body><\/html>\n***
","protected":false},"excerpt":{"rendered":"
By Ezzy Pearson Published: Thursday, 28 March 2024 at 08:53 AM Since the first exoplanets were discovered in the mid ’90s, the field of hunting for planets beyond our Solar System has exploded. It seems like every week now, there’s a new discovery, be that of super Earths and mini Neptunes, or hot Jupiters orbiting […]<\/p>\n","protected":false},"author":24,"featured_media":56570,"template":"","categories":[1],"acf":{"readingTimeMinutes":"5"},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/03\/life-imbalances-earths-atmosphere-now-scientists-are-using-this-knowledge-to-search-for-alien-life.jpg",1200,900,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/03\/life-imbalances-earths-atmosphere-now-scientists-are-using-this-knowledge-to-search-for-alien-life-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/03\/life-imbalances-earths-atmosphere-now-scientists-are-using-this-knowledge-to-search-for-alien-life-300x225.jpg",300,225,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/03\/life-imbalances-earths-atmosphere-now-scientists-are-using-this-knowledge-to-search-for-alien-life-768x576.jpg",768,576,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/03\/life-imbalances-earths-atmosphere-now-scientists-are-using-this-knowledge-to-search-for-alien-life-1024x768.jpg",800,600,true],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/03\/life-imbalances-earths-atmosphere-now-scientists-are-using-this-knowledge-to-search-for-alien-life.jpg",1200,900,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/03\/life-imbalances-earths-atmosphere-now-scientists-are-using-this-knowledge-to-search-for-alien-life.jpg",1200,900,false]},"uagb_author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/author\/importmanagerhubsprylab-com\/"},"uagb_comment_info":0,"uagb_excerpt":"By Ezzy Pearson Published: Thursday, 28 March 2024 at 08:53 AM Since the first exoplanets were discovered in the mid ’90s, the field of hunting for planets beyond our Solar System has exploded. It seems like every week now, there’s a new discovery, be that of super Earths and mini Neptunes, or hot Jupiters orbiting…","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed\/56569"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/types\/rss_feed"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/users\/24"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media\/56570"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=56569"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=56569"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

Gases – or biosignatures – can reveal whether there is life on an exoplanet. Credit: Darryl Fonseka\/iStock\/Getty Images<\/figcaption><\/figure>
Certain chemicals in an exoplanet’s atmosphere would indicate the presence of life<\/a> on its surface: these are known as biosignatures<\/a>.<\/p>
We know that life on Earth creates waste gases that unbalance our atmosphere. Now astronomers are seeking similarly off-kilter worlds in the hunt for alien life.<\/p>
Jayne Birkby is an associate professor of exoplanetary science at the University of Oxford.<\/p>
We spoke to her to find out more about her research into searching for life in the atmospheres of planets orbiting stars beyond our Sun.<\/p>
$\"jayne$ <\/figure>
How do you use exoplanet atmospheres to look for life?<\/strong><\/h2>
Life impacts our atmosphere on Earth. The amount of oxygen in our atmosphere is in a disequilibrium state; there\u2019s something constantly replenishing it in our atmosphere \u2013 and that\u2019s life.<\/p>
If all life on Earth was to suddenly disappear, the oxygen in our atmosphere would disappear.<\/p>
The idea is that if we can see the same signature of disequilibrium elsewhere, that starts to become a signature that maybe life is causing that.<\/p>
What molecules are you looking for?<\/strong><\/h2>
There are four main molecules that we focus on when talking about Earth-like life: oxygen, water, carbon dioxide and methane.<\/p>
There are other less abundant things out there that might signal life as well, molecules that can only be made by life.<\/p>
But the former are the easiest things for us to look for.<\/p>
It\u2019s the abundance that matters \u2013 on Earth, we have 21% oxygen.<\/p>
The molecule itself also makes it easier to observe, as it has a strong absorption line in its spectrum, which makes it easier to detect.\u00a0<\/p>
$\"The$
The radial velocity method of exoplanet detection looks for a shift in the spectrum of star light as a star wobbles due to the gravitational pull of an exoplanet in orbit around it. Credit: ESA<\/figcaption><\/figure>
How do you observe exoplanet atmospheres?<\/strong><\/h2>
As a planet orbits, it causes its star to wobble back and forth because of the gravitational pull of that star.<\/p>
The star is wobbling at a few centimetres or metres per second. Meanwhile, the planet is whizzing around at kilometres per second.<\/p>
That means if you were to observe the spectra of the planet you would see it Doppler-shifting back and forth, while the star by comparison would look almost stationary.<\/p>
Remove everything that isn\u2019t moving in wavelength over time and what you\u2019re left with \u2013 buried in a lot of noise \u2013 is a spectrum.<\/p>
If we do this at a high resolution, there are many lines, so it\u2019s a very robust detection.<\/p>
What kind of planets do you observe?<\/strong><\/h2>
The important thing about this technique is that it works on non-transiting exoplanets. That meansit makes the nearest planets accessible.<\/p>
With our current facilities, telescopes in the eight-to-10-metre class, we\u2019re looking in detail at hot Jupiters.<\/p>
We\u2019re starting to push towards the mini-Neptunes \u2013 we really don\u2019t know much about these planets at all.<\/p>
About 75 planets have been observed at high spectral resolution, finding molecules and atomic species in the atmospheres.<\/p>
For the very specific method of high resolution with cross correlation that I do, the number is more like 50\u201360 planets.<\/p>
$\"Most$
Most of the new exoplanets found so far are in between Earth and Neptune in size, so-called super-Earths and mini-Neptunes. Credit: NASA\/ESA\/CSA and STScI<\/figcaption><\/figure>
How common are the molecules that you\u2019re looking for?<\/strong><\/h2>
We see water pretty much everywhere. We find carbon monoxide in a lot of hot Jupiters too.<\/p>
This is all expected from standard equilibrium chemistry.<\/p>
Carbon dioxide has only been confidently seen with low-resolution spectra from space.<\/p>
Methane is tentatively seen using the high-resolution method in hot Jupiters, but has been seen at lower resolution with the James Webb Space Telescope for a sub-Neptune planet.<\/p>
Oxygen has not been detected. None of these suggests any evidence of life.<\/p>
That would be more for the rocky planets, which we haven\u2019t looked at yet at high resolution.\u00a0<\/p>
$\"Artist's$
Artist’s impression of the European Extremely Large Telescope in operation. Credit: ESO\/L. Cal\u00e7ada<\/figcaption><\/figure>
How could you examine rocky worlds?<\/strong><\/h2>
We need the Extremely Large Telescope, due to start operations in 2028. It will have a 39-metre-diameter mirror \u2013 we need that big \u2018light bucket\u2019.<\/p>
The goal is to make a census of rocky planets and see how many of them are like Earth.<\/p>
Maybe they\u2019re all like Venus \u2013 really hot, with a sulphuric atmosphere that\u2019s inhospitable to life.<\/p>
Or maybe they\u2019re like Mars, just arid deserts.\u00a0<\/p>
Water and methane, in particular, have quite complex spectra that make them harder to distinguish, so the fact that we can find molecules in hot gas giant planets is good news for searching for biosignatures on rocky worlds.<\/p>
It means when we look at rocky planets where we might hope to find life and where these molecules could be biosignatures, we know that our methods will work.<\/p>
***This interview appeared in the April 2024 issue of BBC Sky at Night Magazine<\/em><\/strong><\/p> <\/body><\/html>\n***
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By Ezzy Pearson Published: Thursday, 28 March 2024 at 08:53 AM Since the first exoplanets were discovered in the mid ’90s, the field of hunting for planets beyond our Solar System has exploded. It seems like every week now, there’s a new discovery, be that of super Earths and mini Neptunes, or hot Jupiters orbiting […]<\/p>\n","protected":false},"author":24,"featured_media":56570,"template":"","categories":[1],"acf":{"readingTimeMinutes":"5"},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/03\/life-imbalances-earths-atmosphere-now-scientists-are-using-this-knowledge-to-search-for-alien-life.jpg",1200,900,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/03\/life-imbalances-earths-atmosphere-now-scientists-are-using-this-knowledge-to-search-for-alien-life-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/03\/life-imbalances-earths-atmosphere-now-scientists-are-using-this-knowledge-to-search-for-alien-life-300x225.jpg",300,225,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/03\/life-imbalances-earths-atmosphere-now-scientists-are-using-this-knowledge-to-search-for-alien-life-768x576.jpg",768,576,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/03\/life-imbalances-earths-atmosphere-now-scientists-are-using-this-knowledge-to-search-for-alien-life-1024x768.jpg",800,600,true],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/03\/life-imbalances-earths-atmosphere-now-scientists-are-using-this-knowledge-to-search-for-alien-life.jpg",1200,900,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/03\/life-imbalances-earths-atmosphere-now-scientists-are-using-this-knowledge-to-search-for-alien-life.jpg",1200,900,false]},"uagb_author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/author\/importmanagerhubsprylab-com\/"},"uagb_comment_info":0,"uagb_excerpt":"By Ezzy Pearson Published: Thursday, 28 March 2024 at 08:53 AM Since the first exoplanets were discovered in the mid ’90s, the field of hunting for planets beyond our Solar System has exploded. It seems like every week now, there’s a new discovery, be that of super Earths and mini Neptunes, or hot Jupiters orbiting…","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed\/56569"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/types\/rss_feed"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/users\/24"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media\/56570"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=56569"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=56569"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}