NASA recently announced the addition of 65 newly confirmed planets to its archive, bringing the current number of exoplanets in our galaxy to 5,005. Scientists have observed enough exoplanets to get some interesting ideas about the universe. But the inspiring power behind this entire quest – finding life on another planet – has yet to be realized.
Why is this important?The search for exoplanets has enabled scientists to place Earth and the rest of our solar system in a cosmic context. So far they see Earth as very rare. There is also a growing awareness that even if we find a new Earth, the chances of humanity at any point in reaching a planet where there is or may be life is unreal.
So our universe is full of other worlds that revolve around their suns. For most of human history, this was only an assumption rather than a fact; Astronomers can only look at distant stars through telescopes and daydream about planets that may be hiding in their glow.
But then, about 30 years ago — very recently, when you think about how long people stare at the sky — the harsh, cold data came out. Astronomers are beginning to detect signals from worlds outside our solar system – at first only a few, and then, as more complex instruments become available, hundreds and hundreds. And now, according to NASA figures, the number of confirmed exoplanets in our Milky Way has exceeded 5,000.
It turns out that nature is capable of producing all kinds of worlds
Scientists have observed enough exoplanets to get some interesting ideas about the universe. It turns out that nature is capable of producing all kinds of worlds. There are exoplanets smaller than Mercury and those that are twice the size of Jupiter. It can be freezing cold or hot. It can be rocky but it is not. Or invasive, with clouds all the way up. There are planets around the star closest to our sun, only 4.2 light years away, and planets around stars a few thousand light years away.
Astronomers can say with confidence, based on their findings so far, that our Milky Way should contain more planets than stars. But the inspiring power behind this entire quest – finding life on another planet – has yet to be realized.
Astronomers have discovered rocky exoplanets roughly the size of Earth, some of which are in the habitable zones of their stars, where conditions are just right for liquid water. But no one has yet found evidence of life in the atmosphere of another planet, nor has it detected radio emissions from a distant world.
Astronomers can predict how many planets there are, but they cannot say how many planets we will need to discover other Earths or any sign of alien life. Even with over 5,000 other scientists on the books, we’re still on our own. Scientists could find an additional 5,000 exoplanets and we could be as alone as we are right now.
Kepler, TRAPPIST and the James Webb Space Telescope
The first known exoplanets were discovered in the early 1990s using ground-based telescopes that were able to “pick up” stars swaying on their axis, an indication that a planet may have been in close orbits. The case really exploded after the launch of a NASA probe called Kepler in 2009. From its place in space, Kepler observed hundreds of thousands of stars, this time looking for small dips in brightness, a sign that the planet is blocking the glow of its orbiting star as it passes into orbit in front of it. . Kepler has made it possible to discover about two-thirds of the 5,005 known exoplanets. NASA retired from Kepler in 2018 when the probe ran out of fuel.
Over the years, exoplanets have delighted scientists but also confused them. The abundance of hot Jupiters – scorching giant worlds orbiting their stars in a matter of days – has upended traditional planet-formation theories, which have failed to explain such massive gaseous planets orbiting near their suns.
The discovery of multi-planetary systems suggested that the arrangement of our solar system might be a common occurrence. Some of the discoveries sounded familiar and strange at the same time. Take, for example, the planets around a star called TRAPPIST-1, which are about 40 light-years away, which were discovered in 2017. There are seven, all the size of Earth and rocks. But their Sun is no larger than Jupiter, and a year on the outer planet lasts only 20 days.
This distant system could theoretically be home to a living thing because three of its planets orbit within the star’s habitable zone. Astronomers don’t know anything about their atmosphere yet, but they will soon Take a chance with the James Webb Space Telescopewhich can pick up certain molecules that we know may be related to life.
What we have learned so far is that our earth is rare
The search for exoplanets has enabled scientists to place Earth and the rest of our solar system in a cosmic context. So far they see Earth as very rare. We haven’t yet found a truly Earth-like planet: a rocky world the size of our own, with a chemical-rich atmosphere and surface temperatures that allow water to stay, or ripple, rather than evaporate or freeze. But this did not deter alien hunters, especially those interested in finding evidence not of microbial life, but of advanced civilizations.
When it turns out that a star has a planet, even if it’s not Earth-like at all, SETI astronomers point their telescope antennas at the star, in case there’s another planet hidden in that system, and broadcast on a frequency we can pick up. More exoplanet discoveries will give scientists more opportunities to do this kind of work. But can 5,000 exoplanets, or even 10,000 or 20,000, bring us closer to the answer to this great existential question?
It does not depend on the size of the inventory or the complexity of our instruments, but rather on the universe itself, and how ordinary – or not – life is. Astronomers will continue to search for more exoplanets, driven by the belief that in a galaxy the size of our Milky Way, filled with many stars and even more planets, life is more common than current statistics indicate.
Roll the right dice
If you ask astronomers how many planets are in the universe (possible), they will say that there are only two answers to this question. It is either one (ours) or infinitely many. If we were to discover life on another planet, the answer immediately jumps to infinity. The reason: You can imagine a universe in which the confluence of factors that make life possible is so complex that a correct dice roll can occur statistically only once, in this case on Earth. But if it can happen more than once, why is there a limit?
We all hope for the latter. It would be a very lonely universe if we were the only planet with lights on. And with the recent explosion in exoplanet discovery, our chances that we’re not alone seem to grow more and more. Astronomers now believe that every star in the Milky Way orbits at least one planet. Know that there are 250 billion stars in our Milky Way and about 100 billion more galaxies beyond, each containing hundreds of billions of stars — which potentially provide trillions of places for life to thrive.
Cold Truth: All the stars outside our solar system are beyond human reach
But let’s break the illusion at once: even if we find it, the chances of humanity landing on a planet where there is or could be life is unrealistic. We will never migrate to the exoplanets that we discover, however convenient it may be for us. All known exoplanets, or planets outside our solar system, are simply too far away to travel to. Even in the very optimistic case of a habitable planet not too far away, a few tens of light years, which is not much, the time to get there is too long.
We may be able to send humans to Mars in the next 50 yearsAlthough this is frankly questionable), but it could take centuries for humanity to reach Jupiter’s orbit. The distance to the nearest star outside our solar system is 70,000 times greater than the distance to Jupiter.
You could say a lot of things seemed so farfetched until we got to it anyway. Supersonic flight from one continent to another, for example. Or go to the moon. In 1903, the editors of the New York Times stated that “it would take at least a million years to make a flying machine” and just nine weeks later, the Wright brothers were making history. But this is not an argument. Getting physics to the stars requires a fundamental change in our understanding of the relationship between mass, acceleration, and energy. The cold truth is that all stars outside our solar system are beyond the reach of humanity.
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