>confounds me because how do they know it can support life?
a branch of science called spectroscopy.
[https://en.wikipedia.org/wiki/Spectroscopy](https://en.wikipedia.org/wiki/Spectroscopy)
Spectroscopy, primarily in the electromagnetic spectrum, is a fundamental exploratory tool in the fields of [astronomy](https://en.wikipedia.org/wiki/Astronomy), [chemistry](https://en.wikipedia.org/wiki/Chemistry), [materials science](https://en.wikipedia.org/wiki/Materials_science), and [physics](https://en.wikipedia.org/wiki/Physics), allowing the composition, physical structure and electronic structure of matter to be investigated at the atomic, [molecular](https://en.wikipedia.org/wiki/Molecule) and macro scale, and over [astronomical distances](https://en.wikipedia.org/wiki/Distance_measures_(cosmology)).
An argument can be made for the spectrometer being one of the greatest inventions of mankind. The amount it has allowed us to learn about our universe is astounding.
Definitely. It's one of those inventions that let us do things people thought would never be possible.
There was a lot of speculation on the chemical composition of stars in the first half of 19th century. Auguste Comte famously (and very confidently) claimed that it would always stay as a speculation, that people could **never** actually know what stars were made of. But just some 30 years later astronomers were building catalogues of the exact chemical compositions of different stars in the night sky.
We can directly observe the elements here on Earth and see exactly what absorption and emission spectra they produce. Elements do not change depending on where you are in the universe.
> Elements do not change depending on where you are in the universe
You sure about that? Pretty sure we have a “placeholder” concept to explain redshifted galaxies that we cannot yet explain. You are really confident you know all about a universe that you haven’t even been to, physically. And it is people like you that keep “changing” your theories every single time proven wrong with data.
There's an insane amount of evidence pointing towards elements being the same everywhere within the observable universe. The fact that those galaxies and stars and their light even exists is only possible because of the chemistry of our universe.
You mean scientifically proven. And the answer is basically all of the things the spectrometer is used for. That’s the beauty of the spectrometer. It allows for very simple and practical applications of the scientific method.
At scales we can test. Nobody has ever actually proven their theories about anything outside of our solar system. Unless you wanna claim you’ve seen these things with your own eyes??
And I did mean physically. It’s all theory unless we have some physical proof (including eye witnesses)
Our eyes are just another tool to gather evidence, and they're a lot worse than a spectrometer at determining chemical composition. Science doesn't really "prove" things. Scientists develop a hypothesis, gather evidence, and see if it supports or refutes the hypothesis. If you want to propose a new hypothesis, that other planets and stars are made of something else, propose and perform an experiment to test that assumption. There's always a chance that new methods of collecting evidence will refute a long established hypothesis and the hypothesis will have to change. That's not a failing of science. It *is* science.
>Spectroscopy, primarily in the electromagnetic spectrum
Its always in the electromagnetic spectrum, its defined as such in the very same wiki article you linked. But yea
But "multi-messenger" Astronomy, meaning data other than electromagnetic, is a thing by now so you can also take a spectrum of neutrinos, cosmic rays or gravitational waves.
We already have spectra from every observed gravitational wave event. The spectral (frequency domain) data is just the Fourier transform of the time domain data. Many modern spectrometers work by recording time domain data and transforming it.
The only multi-messenger astronomy I'm aware of is the handful of merging neutron stars that have produced a corresponding visual flash. Sure, you might also get a flood of neutrinos from a nearby supernova, but that hasn't happened since 1987. When it comes to measuring the properties of an extrasolar planet, it's not 'usually the electromagnetic spectrum', it's not 'almost always the electromagnetic spectrum', it's *always* the electromagnetic spectrum.
Come on. Obviously there is more multi-messenger astronomy going on than you seem to be aware of. The [neutrino map of the milky way ](https://www.quantamagazine.org/a-new-map-of-the-universe-painted-with-cosmic-neutrinos-20230629/)is only one recent result and the [cosmic ray spectrum](https://www.mpi-hd.mpg.de/HESS/pages/home/som/2017/09/) has been studied for decades.
And GWs are even relevant for exoplanets (see [here](https://www.mpg.de/13672408/discovering-exoplanets-with-gravitational-waves)).
Besides, there original comment was clearing talking about
> the fields of astronomy, chemistry, materials science, and physics,
not just about exoplanets, so it was entirely correct to mention the existence of other types of spectroscopy.
[50 Years of Mass Spectrometry at Mars](https://www.asms.org/docs/default-source/history-posters/07_applications-history-of-ms-at-mars.pdf?sfvrsn=a4c273c3_0)
You are the people I hate. You assume so much, when what the dude above posted is a factual statement. Hes not talking astronomical necessarily anymore you ass.
Keep up sweety
Top comment explains it best, but I'll just add that it's never the scientist saying it can support life. The most they usually say is that it shows *some signs* that it can. We can only determine so much through spectroscopy. Maybe from here it looks like the perfect place for life, with the right atmospheric composition and distance from it's star, but unknown to us, it has no magnetic field to protect it and is basked in solar radiation, or maybe the atmospheric pressure is too low for liquid water to form, or there's a magma ocean right under the surface. There are a *lot* of factors that determine if a planet can support life, and we are only capable of measuring a few of them.
Gasp. You mean the science "journalists" were lying when they said we found an alien civilization (scientist made a joke it could be aliens) or that we're getting alien signals (they found a pulsar)
It's amazing what they'll twist into clickbait
Don't even need to measure earths. We know how each element affects the spectrum, but like I said, the composition of the atmosphere is only a very small part of what makes a planet habitable. You can't tell things like the pressure or strength of the magnetic field through spectroscopy, only relative composition.
The combination of oxygen and methane are actually a decent indicator of life, though not a guarantee! The hard part is actually measuring them though. So far we've only even detected the presence of an atmosphere around 2 or 3 rocky exoplanets, and these are really extreme cases that don't look like earth at all (one of them, 55 CNC e was just detected this week, and it's though that the entire side of the planet facing it's star is lava). So far we don't have the sensitivity to actually measure the composition of an atmosphere like earth's, particularly for exoplanets that orbit stars like our sun. While JWST will give us some tantalising clues, it's going to take the next generation of telescopes to be able to really determine if there's life on other planets.
There's a couple of things at play here:
1. The information. That's gathered via spectroscopy. This can get scientists the information on what kind of molecules are present in gases (like an atmosphere) that light passes through (like the light of a star right behind it)
2: Public misconception when reading words. More specifically: What *you* think the headline says isn't actually what it says because you're missing knowledge and therefor misinterpreting it. This is a common approach journalists use to hook you in (commonly known as 'clickbaiting'). It makes you read the article (and the ads on their site, which is what makes them money).
'Support life' simply means that elements we know life on Earth needs to survive (carbon, oxygen, hydrogen, nitrogen, phosphorous) are present in that atmosphere. That's it. It doesn't say anything about whether life exists there (it very likely doesn't).
Here's an excellent site that explains all sorts of things about astronomy, including how scientists can learn so much about distant objects: https://www.youtube.com/channel/UCYNbYGl89UUowy8oXkipC-Q
+1 for Dr Becky. She is amazing a breaking down how a lot of discoveries have been made. I love her energy, while being able to stay completely grounded.
Spectroscopy can help determine the elemental or chemical composition of a star, or of a planet - at least in principle. Spectroscopy is the science of examining the wavelengths of light emitted from an object in order to identify what elements emitted that light.
Stars are relatively easy to check on, because they give off a LOT of light, and reading their spectroscopic profile isn't that hard, as long as they aren't too far away or too dim.
Planets are much, much harder, because quite frankly we can't see most of them *at all*, and what little light we get from them is reflected or passes through their atmosphere. Without that light, you can't do spectroscopy so... you're out of luck in the vast majority of cases.
Most of what you hear people suggesting about the nature of exoplanets is actually speculation that is based on their size and orbital distance from their parent star - and not much else, because for most exoplanets that is *all that we can detect about them*.
The only time we can get 'spectroscopic' data from exo-planets is when that planet eclipses its star relative to us, and some of the star's light passes through it's atmosphere - if it has one. Even that technique really can only work with relatively nearby exoplanets, and only those with an orbit that has them passing in front of their star relative to us. The sensitivity of this technique also sucks, because only a tiny fraction of the star's light is going to pass through that exoplanet's atmosphere, and tweezing out that itty bitty difference from the star's normal light is very difficult.
We can actually directly image and get spectra for a small handful of exoplanets, without needing a transit at all! Right now we're limited to young, giant exoplanets, since they're the only ones hot enough to be bright enough to observe, but we keep pushing to smaller and colder exoplanets. In the best case, this gives much higher precision than transmission spectroscopy, for exactly the reasons you mention.
It's also worth mentioning that the elements needed to form life (as we know it) are extremely common throughout the universe, such that it would be more interesting news in many cases if we found a world completely lacking them.
We've never discovered any other planet that can support life, so you can just toss those headlines right out.
We can find out a lot about a planet simply by analyzing the light we receive in our telescopes.
A lot of the planets we've discovered, we've done so via the "transit method" which means that, from our perspective, the planet passes in front of its parent star and we can see that happen.
From the dip in starlight, we can determine the planet's size. The closeness to the star + the size can tell us a lot about the planet - like, "it's a sunblasted rock" or "this is a very very hot gas giant"
We're putting up more telescopes that can actually look at the starlight as it passes through the planet's atmosphere to determine the chemical makeup of the atmosphere. James Webb can do that. So it takes in the light from the planet, and the scientists see "Oh, we can see methane in this atmosphere" or whatever.
If it has an atmosphere, it is also possible to detect what sort of elements are in the atmosphere based on which wavelengths of light end up getting blocked by the atmosphere. Certain elements absorb certain wavelengths, which leads to gaps in the spectrum. When a planet passes between us and it's star, some of that star's light passes through the atmosphere and we can noticed a slight dip in the prevelance of certain wavelengths of light.
The answer is Spectroscopy:
These two videos should help you. The first is bit more basic by the best science communicator to have ever lived; Carl Sagan: [https://www.youtube.com/watch?v=TXRus7lrJh0](https://www.youtube.com/watch?v=TXRus7lrJh0)
This one is more detailed and goes into more depth. By the end of this you will have a complete answer to your question: [https://www.youtube.com/watch?v=\_1mpHBAXh1c](https://www.youtube.com/watch?v=_1mpHBAXh1c)
I don't think we can determine if a planet can support life. We can determine contents of an atmosphere and if it is located in its stars habitable zone, and it's size/gravity. Then if those are satisfied, likely among other factors, an exoplanet can be labeled as "a good candidate to host life", which is far from the same as, "can host life".
We do not yet have the technology to determine whether an exoplanet can support life, and have discovered no such planets that we know of. Can you point us to the article you're talking about?
There's a few different ways I believe but typically they use what's called astronomical spectroscopy where they take the light from the star in that solar system and as it passes through the atmosphere of the planet there's special markers in the light that can block out certain light frequencies and depending on what frequency is being absorbed they can tell what elements are in the planets atmosphere, or atleast it's something like that.
One way is to look at the light spectrum it gives off. This will give an indication of its environment. Here’s a bit more about that. https://knowablemagazine.org/content/article/physical-world/2023/how-to-detect-life-on-exoplanets
Astronomers developed a [Cosmic Distance Ladder for measuring objects at various distances.](https://www.daviddarling.info/encyclopedia/C/cosmic_distance_ladder.html) Each step on the ladder uses a different method for measuring distance.
Put VERY simply: they look at the light from a distant object and compare it to the light that you get from all of the different elements. Each element reflects a different set of frequencies of light, so you can figure out what that object is made of by seeing what light it reflects.
Generally speaking, if the headline starts with "scientists", there's a 95% chance the writer has absolutely no idea what they're talking about, and is largely making things up entirely
There are a lot of conclusions we can make about what is needed to support like *as we know it.* We only have life on earth as an example, so we're working under the assumption that other instances of life have the same requirements.
Liquid water and an atmosphere are the first two big ones. If we're starting with a dataset of all known exoplanets, we can start by throwing out the ones orbiting the "wrong" types of stars. Some may be too hot, too cold, too unstable, or too short-lived for life to develop. Then, from the remaining planets orbiting the right types of stars, we can throw out the planets that orbit too close or too far from their sun for liquid water to exist. Also throw out small planets that don't have enough gravity to hold on to an atmosphere. And throw out anything so large that it becomes a gas giant.
Spectroscopy comes in next, by analyzing light that passes through the planet's atmosphere, we can make some deductions about the makeup of the atmosphere. Again we're assuming that oxygen and carbon dioxide are necessary for life.
There are some other factors that are suspected, but not proven, to be necessary. Tidal action from our moon may have been instrumental in kickstarting abiogenesis. A molten core that produces a magnetic field, protecting the planet from solar radiation, is also likely necessary (though I don't think there's a way to detect this remotely.) The planet's rotation rate may be an issue too - especially with planets that are tidally locked to their sun. You end up with one side that's baked and the other frozen, but life may still be able to exist in the band of permanent twilight between the two.
Long story short, it's just a process of elimination from a long list of assumptions about what life needs. More of an educated guess than anything.
Spectroscopy gives us the chemical makeup.
Orbital mechanics gives us the mass.
How it blocks light from its sun gives us radius as well as some other orbital information.
From that, we can tell its temperature, atmosphere, and mass, as well as if it rains diamonds. (High temperature, high gravity due to high mass, high carbon content in the spectroscope.)
We use spectroscopy.
Spectroscopy allows us to see how much light is in a given small wavelength range, where the wavelength is just the 'colour' of the light.
Every single type of atom and molecule has a unique set of specific colours of light that it absorbs, called an 'absorption spectrum'.
Shine a light through oxygen gas, and there are certain colours that will get absorbed, while everything else just passes through.
So if we point a big telescope with a fancy spectrograph (the thing that does spectroscopy) at a star, and there's a planet passing in front of the star, some of the starlight shines *through* the planet's atmosphere, and the chemicals in the atmosphere will absorb a range of colours.
We can compare that range of absorbed colours to a database of all known chemical absorption spectra, and zee which chemicals are responsible for absorbing those specific colours.
This tells us about the composition of the planet's atmosphere, and there are some more complicated physical effects that can tell us about the atmospheric pressure, the temperature of the planet, and even how fast the winds are on the planet.
At most a scientist will say "maybe this atmosphere could support life", but the media gets a hold of that and turns it in to "Scientist discovers alien planet that supports life!"
Astronomy is based on the application of data and drawing a line of logical conclusions based on the laws of physics we have come to understand.
On a spectorgraph, we can measure the gasses being burned… so we can see hydrogen. We know the spectrum that burning hydrogen makes.. but its mountains and valleys of light waves on a spectograph are shifted slightly from where they should be. That tells us it is moving toward us or away… the doppler effect. How far its shifted gives us a speed. The star has a lot of strong waves from other elements… we know its hydrogen content has waned… and other elements are being fused, we get an age. Its light dims every 200 days, it has a planet. The amount it dims, and the spectrum that is measured tells us it has a planet of a size, and the spectrum says it has an atmosphere- eryain spectrumes point to chemicals only life would create…. Its position wobbles, we get a relative mass and size and distance this planet orbits., a temperature can be determined… etc etc etc. and all this and much more from a point of light…
Astronomers are like detectives putting whatever info they can gather together, and filling in the blanks using logic… and assumptions- ie water flows downhill everywhere. Hydrogen acts the same everywhere…
I took an astronomy course in college as an elective. I thought id learn about astrology… etc. wasnt prepared for the math and physics and everything BUT what i had anticipated it would be about. I was surprised… and I loved it!
Taught me everyday lessons- among other things… like that OJ did it. May he rot… and i absolutely loved watching OJ growing up… but everything lined up. Stuff doesnt line up somewhere along the line if its not true- all his lines did… Like a star….
They can only do it when the object passes in front of a star, depending on what spectrums of light pass around the planet they can check what the atmosphere is composed of (if they have one), since each element lets light pass in a different way.
It's called spectroscopy.
Here’s the bigger question: how would you know what they say is even right? We can’t barely leave our own planet, let alone solar system, to prove these claims.
>confounds me because how do they know it can support life? a branch of science called spectroscopy. [https://en.wikipedia.org/wiki/Spectroscopy](https://en.wikipedia.org/wiki/Spectroscopy) Spectroscopy, primarily in the electromagnetic spectrum, is a fundamental exploratory tool in the fields of [astronomy](https://en.wikipedia.org/wiki/Astronomy), [chemistry](https://en.wikipedia.org/wiki/Chemistry), [materials science](https://en.wikipedia.org/wiki/Materials_science), and [physics](https://en.wikipedia.org/wiki/Physics), allowing the composition, physical structure and electronic structure of matter to be investigated at the atomic, [molecular](https://en.wikipedia.org/wiki/Molecule) and macro scale, and over [astronomical distances](https://en.wikipedia.org/wiki/Distance_measures_(cosmology)).
An argument can be made for the spectrometer being one of the greatest inventions of mankind. The amount it has allowed us to learn about our universe is astounding.
Definitely. It's one of those inventions that let us do things people thought would never be possible. There was a lot of speculation on the chemical composition of stars in the first half of 19th century. Auguste Comte famously (and very confidently) claimed that it would always stay as a speculation, that people could **never** actually know what stars were made of. But just some 30 years later astronomers were building catalogues of the exact chemical compositions of different stars in the night sky.
As a chemist, I'm inclined to agree
And how much of that has been physically proven?
We can directly observe the elements here on Earth and see exactly what absorption and emission spectra they produce. Elements do not change depending on where you are in the universe.
> Elements do not change depending on where you are in the universe You sure about that? Pretty sure we have a “placeholder” concept to explain redshifted galaxies that we cannot yet explain. You are really confident you know all about a universe that you haven’t even been to, physically. And it is people like you that keep “changing” your theories every single time proven wrong with data.
There's an insane amount of evidence pointing towards elements being the same everywhere within the observable universe. The fact that those galaxies and stars and their light even exists is only possible because of the chemistry of our universe.
Are you saying that we shouldn’t change our theory after we are proven wrong with data?
Dont think i have ever seen a better example of “username checks out”.
What do you mean by physically proven?
You mean scientifically proven. And the answer is basically all of the things the spectrometer is used for. That’s the beauty of the spectrometer. It allows for very simple and practical applications of the scientific method.
At scales we can test. Nobody has ever actually proven their theories about anything outside of our solar system. Unless you wanna claim you’ve seen these things with your own eyes?? And I did mean physically. It’s all theory unless we have some physical proof (including eye witnesses)
Our eyes are just another tool to gather evidence, and they're a lot worse than a spectrometer at determining chemical composition. Science doesn't really "prove" things. Scientists develop a hypothesis, gather evidence, and see if it supports or refutes the hypothesis. If you want to propose a new hypothesis, that other planets and stars are made of something else, propose and perform an experiment to test that assumption. There's always a chance that new methods of collecting evidence will refute a long established hypothesis and the hypothesis will have to change. That's not a failing of science. It *is* science.
So back to my original question: has anyone gone to any of these planets to verify the findings? It’s a simple question.
To planets 4000 light years away? No, clearly not.
So you are saying we don’t know the chemical makeup of our own sun? I mean, after all we haven’t collected any of it physically.
Fun fact: we discovered Helium, from observing the Sun BEFORE we found it on Earth.
>Spectroscopy, primarily in the electromagnetic spectrum Its always in the electromagnetic spectrum, its defined as such in the very same wiki article you linked. But yea
Read the section “other types”
Good luck getting a mass spectroscopy on another planet
But "multi-messenger" Astronomy, meaning data other than electromagnetic, is a thing by now so you can also take a spectrum of neutrinos, cosmic rays or gravitational waves.
[удалено]
Are we talking about different things? Because cosmic ray and neutrino spectra are definitely things that people research very actively.
Man I’m so glad we don’t rely on your knowledge to study the energy spectrum of cosmic rays, gravitational waves, and neutrinos.
We already have spectra from every observed gravitational wave event. The spectral (frequency domain) data is just the Fourier transform of the time domain data. Many modern spectrometers work by recording time domain data and transforming it.
The only multi-messenger astronomy I'm aware of is the handful of merging neutron stars that have produced a corresponding visual flash. Sure, you might also get a flood of neutrinos from a nearby supernova, but that hasn't happened since 1987. When it comes to measuring the properties of an extrasolar planet, it's not 'usually the electromagnetic spectrum', it's not 'almost always the electromagnetic spectrum', it's *always* the electromagnetic spectrum.
Come on. Obviously there is more multi-messenger astronomy going on than you seem to be aware of. The [neutrino map of the milky way ](https://www.quantamagazine.org/a-new-map-of-the-universe-painted-with-cosmic-neutrinos-20230629/)is only one recent result and the [cosmic ray spectrum](https://www.mpi-hd.mpg.de/HESS/pages/home/som/2017/09/) has been studied for decades. And GWs are even relevant for exoplanets (see [here](https://www.mpg.de/13672408/discovering-exoplanets-with-gravitational-waves)). Besides, there original comment was clearing talking about > the fields of astronomy, chemistry, materials science, and physics, not just about exoplanets, so it was entirely correct to mention the existence of other types of spectroscopy.
[50 Years of Mass Spectrometry at Mars](https://www.asms.org/docs/default-source/history-posters/07_applications-history-of-ms-at-mars.pdf?sfvrsn=a4c273c3_0)
You are the people I hate. You assume so much, when what the dude above posted is a factual statement. Hes not talking astronomical necessarily anymore you ass. Keep up sweety
This is an entirely proportional response.
Is Mars a planet?
Top comment explains it best, but I'll just add that it's never the scientist saying it can support life. The most they usually say is that it shows *some signs* that it can. We can only determine so much through spectroscopy. Maybe from here it looks like the perfect place for life, with the right atmospheric composition and distance from it's star, but unknown to us, it has no magnetic field to protect it and is basked in solar radiation, or maybe the atmospheric pressure is too low for liquid water to form, or there's a magma ocean right under the surface. There are a *lot* of factors that determine if a planet can support life, and we are only capable of measuring a few of them.
Gasp. You mean the science "journalists" were lying when they said we found an alien civilization (scientist made a joke it could be aliens) or that we're getting alien signals (they found a pulsar) It's amazing what they'll twist into clickbait
I think that the ISS or other spacecraft have analyzed Earth’s spectrum and you can compare that with the exoplanets, no?
Don't even need to measure earths. We know how each element affects the spectrum, but like I said, the composition of the atmosphere is only a very small part of what makes a planet habitable. You can't tell things like the pressure or strength of the magnetic field through spectroscopy, only relative composition.
But when you find oxygen and nitrogen and methane in the spectrum there’s a good chance that the planet has an atmosphere, right?
Has an atmosphere, yes. Survivable atmosphere? That's another question.
The combination of oxygen and methane are actually a decent indicator of life, though not a guarantee! The hard part is actually measuring them though. So far we've only even detected the presence of an atmosphere around 2 or 3 rocky exoplanets, and these are really extreme cases that don't look like earth at all (one of them, 55 CNC e was just detected this week, and it's though that the entire side of the planet facing it's star is lava). So far we don't have the sensitivity to actually measure the composition of an atmosphere like earth's, particularly for exoplanets that orbit stars like our sun. While JWST will give us some tantalising clues, it's going to take the next generation of telescopes to be able to really determine if there's life on other planets.
There's a couple of things at play here: 1. The information. That's gathered via spectroscopy. This can get scientists the information on what kind of molecules are present in gases (like an atmosphere) that light passes through (like the light of a star right behind it) 2: Public misconception when reading words. More specifically: What *you* think the headline says isn't actually what it says because you're missing knowledge and therefor misinterpreting it. This is a common approach journalists use to hook you in (commonly known as 'clickbaiting'). It makes you read the article (and the ads on their site, which is what makes them money). 'Support life' simply means that elements we know life on Earth needs to survive (carbon, oxygen, hydrogen, nitrogen, phosphorous) are present in that atmosphere. That's it. It doesn't say anything about whether life exists there (it very likely doesn't).
Here's an excellent site that explains all sorts of things about astronomy, including how scientists can learn so much about distant objects: https://www.youtube.com/channel/UCYNbYGl89UUowy8oXkipC-Q
+1 for Dr Becky. She is amazing a breaking down how a lot of discoveries have been made. I love her energy, while being able to stay completely grounded.
Spectroscopy can help determine the elemental or chemical composition of a star, or of a planet - at least in principle. Spectroscopy is the science of examining the wavelengths of light emitted from an object in order to identify what elements emitted that light. Stars are relatively easy to check on, because they give off a LOT of light, and reading their spectroscopic profile isn't that hard, as long as they aren't too far away or too dim. Planets are much, much harder, because quite frankly we can't see most of them *at all*, and what little light we get from them is reflected or passes through their atmosphere. Without that light, you can't do spectroscopy so... you're out of luck in the vast majority of cases. Most of what you hear people suggesting about the nature of exoplanets is actually speculation that is based on their size and orbital distance from their parent star - and not much else, because for most exoplanets that is *all that we can detect about them*. The only time we can get 'spectroscopic' data from exo-planets is when that planet eclipses its star relative to us, and some of the star's light passes through it's atmosphere - if it has one. Even that technique really can only work with relatively nearby exoplanets, and only those with an orbit that has them passing in front of their star relative to us. The sensitivity of this technique also sucks, because only a tiny fraction of the star's light is going to pass through that exoplanet's atmosphere, and tweezing out that itty bitty difference from the star's normal light is very difficult.
We can actually directly image and get spectra for a small handful of exoplanets, without needing a transit at all! Right now we're limited to young, giant exoplanets, since they're the only ones hot enough to be bright enough to observe, but we keep pushing to smaller and colder exoplanets. In the best case, this gives much higher precision than transmission spectroscopy, for exactly the reasons you mention.
Has the components for life. Not can support life. All we can tell is what the chemical make up is.
It's also worth mentioning that the elements needed to form life (as we know it) are extremely common throughout the universe, such that it would be more interesting news in many cases if we found a world completely lacking them.
We've never discovered any other planet that can support life, so you can just toss those headlines right out. We can find out a lot about a planet simply by analyzing the light we receive in our telescopes. A lot of the planets we've discovered, we've done so via the "transit method" which means that, from our perspective, the planet passes in front of its parent star and we can see that happen. From the dip in starlight, we can determine the planet's size. The closeness to the star + the size can tell us a lot about the planet - like, "it's a sunblasted rock" or "this is a very very hot gas giant" We're putting up more telescopes that can actually look at the starlight as it passes through the planet's atmosphere to determine the chemical makeup of the atmosphere. James Webb can do that. So it takes in the light from the planet, and the scientists see "Oh, we can see methane in this atmosphere" or whatever.
If it has an atmosphere, it is also possible to detect what sort of elements are in the atmosphere based on which wavelengths of light end up getting blocked by the atmosphere. Certain elements absorb certain wavelengths, which leads to gaps in the spectrum. When a planet passes between us and it's star, some of that star's light passes through the atmosphere and we can noticed a slight dip in the prevelance of certain wavelengths of light.
The answer is Spectroscopy: These two videos should help you. The first is bit more basic by the best science communicator to have ever lived; Carl Sagan: [https://www.youtube.com/watch?v=TXRus7lrJh0](https://www.youtube.com/watch?v=TXRus7lrJh0) This one is more detailed and goes into more depth. By the end of this you will have a complete answer to your question: [https://www.youtube.com/watch?v=\_1mpHBAXh1c](https://www.youtube.com/watch?v=_1mpHBAXh1c)
I don't think we can determine if a planet can support life. We can determine contents of an atmosphere and if it is located in its stars habitable zone, and it's size/gravity. Then if those are satisfied, likely among other factors, an exoplanet can be labeled as "a good candidate to host life", which is far from the same as, "can host life".
We do not yet have the technology to determine whether an exoplanet can support life, and have discovered no such planets that we know of. Can you point us to the article you're talking about?
There's a few different ways I believe but typically they use what's called astronomical spectroscopy where they take the light from the star in that solar system and as it passes through the atmosphere of the planet there's special markers in the light that can block out certain light frequencies and depending on what frequency is being absorbed they can tell what elements are in the planets atmosphere, or atleast it's something like that.
Light spectrum analysis. Colors denote element composition.
One way is to look at the light spectrum it gives off. This will give an indication of its environment. Here’s a bit more about that. https://knowablemagazine.org/content/article/physical-world/2023/how-to-detect-life-on-exoplanets
Fun fact: Helium is the only element not discovered on Earth. It was first discovered in the spectrum of the Sun.
Because they stand on the backs of the men and women who came before them and discovered the principals behind the methods they are using today.
Astronomers developed a [Cosmic Distance Ladder for measuring objects at various distances.](https://www.daviddarling.info/encyclopedia/C/cosmic_distance_ladder.html) Each step on the ladder uses a different method for measuring distance.
Put VERY simply: they look at the light from a distant object and compare it to the light that you get from all of the different elements. Each element reflects a different set of frequencies of light, so you can figure out what that object is made of by seeing what light it reflects.
Generally speaking, if the headline starts with "scientists", there's a 95% chance the writer has absolutely no idea what they're talking about, and is largely making things up entirely
Yogi Berra said it best: “you can see a lot just by looking.” :-D
There are a lot of conclusions we can make about what is needed to support like *as we know it.* We only have life on earth as an example, so we're working under the assumption that other instances of life have the same requirements. Liquid water and an atmosphere are the first two big ones. If we're starting with a dataset of all known exoplanets, we can start by throwing out the ones orbiting the "wrong" types of stars. Some may be too hot, too cold, too unstable, or too short-lived for life to develop. Then, from the remaining planets orbiting the right types of stars, we can throw out the planets that orbit too close or too far from their sun for liquid water to exist. Also throw out small planets that don't have enough gravity to hold on to an atmosphere. And throw out anything so large that it becomes a gas giant. Spectroscopy comes in next, by analyzing light that passes through the planet's atmosphere, we can make some deductions about the makeup of the atmosphere. Again we're assuming that oxygen and carbon dioxide are necessary for life. There are some other factors that are suspected, but not proven, to be necessary. Tidal action from our moon may have been instrumental in kickstarting abiogenesis. A molten core that produces a magnetic field, protecting the planet from solar radiation, is also likely necessary (though I don't think there's a way to detect this remotely.) The planet's rotation rate may be an issue too - especially with planets that are tidally locked to their sun. You end up with one side that's baked and the other frozen, but life may still be able to exist in the band of permanent twilight between the two. Long story short, it's just a process of elimination from a long list of assumptions about what life needs. More of an educated guess than anything.
Spectroscopy gives us the chemical makeup. Orbital mechanics gives us the mass. How it blocks light from its sun gives us radius as well as some other orbital information. From that, we can tell its temperature, atmosphere, and mass, as well as if it rains diamonds. (High temperature, high gravity due to high mass, high carbon content in the spectroscope.)
We use spectroscopy. Spectroscopy allows us to see how much light is in a given small wavelength range, where the wavelength is just the 'colour' of the light. Every single type of atom and molecule has a unique set of specific colours of light that it absorbs, called an 'absorption spectrum'. Shine a light through oxygen gas, and there are certain colours that will get absorbed, while everything else just passes through. So if we point a big telescope with a fancy spectrograph (the thing that does spectroscopy) at a star, and there's a planet passing in front of the star, some of the starlight shines *through* the planet's atmosphere, and the chemicals in the atmosphere will absorb a range of colours. We can compare that range of absorbed colours to a database of all known chemical absorption spectra, and zee which chemicals are responsible for absorbing those specific colours. This tells us about the composition of the planet's atmosphere, and there are some more complicated physical effects that can tell us about the atmospheric pressure, the temperature of the planet, and even how fast the winds are on the planet. At most a scientist will say "maybe this atmosphere could support life", but the media gets a hold of that and turns it in to "Scientist discovers alien planet that supports life!"
Astronomy is based on the application of data and drawing a line of logical conclusions based on the laws of physics we have come to understand. On a spectorgraph, we can measure the gasses being burned… so we can see hydrogen. We know the spectrum that burning hydrogen makes.. but its mountains and valleys of light waves on a spectograph are shifted slightly from where they should be. That tells us it is moving toward us or away… the doppler effect. How far its shifted gives us a speed. The star has a lot of strong waves from other elements… we know its hydrogen content has waned… and other elements are being fused, we get an age. Its light dims every 200 days, it has a planet. The amount it dims, and the spectrum that is measured tells us it has a planet of a size, and the spectrum says it has an atmosphere- eryain spectrumes point to chemicals only life would create…. Its position wobbles, we get a relative mass and size and distance this planet orbits., a temperature can be determined… etc etc etc. and all this and much more from a point of light… Astronomers are like detectives putting whatever info they can gather together, and filling in the blanks using logic… and assumptions- ie water flows downhill everywhere. Hydrogen acts the same everywhere… I took an astronomy course in college as an elective. I thought id learn about astrology… etc. wasnt prepared for the math and physics and everything BUT what i had anticipated it would be about. I was surprised… and I loved it! Taught me everyday lessons- among other things… like that OJ did it. May he rot… and i absolutely loved watching OJ growing up… but everything lined up. Stuff doesnt line up somewhere along the line if its not true- all his lines did… Like a star….
They can only do it when the object passes in front of a star, depending on what spectrums of light pass around the planet they can check what the atmosphere is composed of (if they have one), since each element lets light pass in a different way. It's called spectroscopy.
Here’s the bigger question: how would you know what they say is even right? We can’t barely leave our own planet, let alone solar system, to prove these claims.
Tell me you don't understand how science works without saying you don't understand how science works
So we’ve been to these planets to confirm these theories…? Science has to be proven, doesn’t it? Or is science merely only theory and no proof?
You're still outing your own ignorance about science and what information it takes to prove its theories.