What if I told you that we have discovered thousands of planets beyond our solar system that are almost identical to Earth? Would you believe us?
Well, it turns out that we have found hundreds of exoplanets that are similar to our planet. Some of these planets even look like they could support life.
The discovery of exoplanets has become a hot topic in recent years. Scientists estimate that there are at least 100 million habitable planets in our galaxy alone. This means that there are plenty of places where life could exist.
But finding them isn’t always easy. For example, some planets are too far away from their star to be detected.
Others are too close to their stars to be habitable. And some planets might be inhospitable because they are tidally locked, meaning they only rotate once per orbit around their sun.
So what are the most Earth-like worlds that we have found so far? This article takes a closer look.
What Are The Most Earth-Like Worlds We’ve Found?
Gliese 581g – A Super-Earth Planet That Could Be Habitable
Gliese 581 is an M dwarf star located 40 light-years away from us. It’s known as a red dwarf star due to its low surface temperature and dimness.
Because of this, Gliese 581 doesn’t emit much heat energy into space. This makes it easier for astronomers to detect the presence of other planets orbiting around it.
In June 2016, researchers used the HARPS spectrograph on ESO’s 3.6 m telescope at La Silla Observatory in Chile to discover a super-earth planet orbiting Gliese 581.
They were able to determine the mass of the new planet by observing the wobble caused by the gravitational pull of the planet. Then, using the radial velocity method, they determined the distance between the star and planet.
After calculating the size of the planet, they realized that it had about twice the radius of Earth. This made them conclude that it was a rocky planet with a lot of iron inside.
However, it also had a very large density which meant that it must contain a significant amount of water. This led them to speculate that it may be capable of supporting life.
Kepler-22b – An Earth-Sized Planet With Water Vapor Lining Its Atmosphere
Kepler 22 b is another super-Earth planet that was discovered in 2014 by NASA’s Kepler Space Telescope.
Like Gliese 581 g, it orbits a red dwarf star called Kepler-22. And much like Gliese 581 G, Kepler 22 b is larger than Earth. It has a diameter of 1.5 times that of Earth and a radius 2.4 times that of Earth.
Kepler 22 b is one of the first exoplanets that was confirmed to have water vapor in its atmosphere.
By analyzing the data collected by Kepler, scientists were able to deduce that the planet has a thick atmosphere. This means that it probably has liquid water underneath its clouds. Liquid water is essential for life as we know it.
Proxima Centauri b – The Closest Exoplanet To Us
Proxima Centauri b is the closest exoplanet to us. Located 4.24 light-years away, it’s the nearest exoplanet to Alpha Centauri. It’s also one of the smallest exoplanets ever discovered. It has a mass of 0.15 Jupiter masses and a radius of 0.11 Earth radii.
It was discovered in August 2017 when European Southern Observatory (ESO) used the Very Large Telescope (VLT) to observe Proxima Centauri b during its transit across its parent star.
During this transit, the VLT observed a decrease in the brightness of the star as the planet passed in front of it.
Scientists then calculated how big the planet should be based on the duration of the transit. From there, they estimated the planet’s mass and radius.
TRAPPIST-1d – A Rocky Planet Surrounded By 7 Smaller Planets
TRAPPIST-1d is one of the most interesting exoplanets found so far. Discovered in 2015, it’s a system of seven rocky planets that are all within the “habitable zone”.
That means that these planets could potentially support liquid water beneath their atmospheres. All of the planets orbit their host star every 26 days.
The innermost planet takes 12 hours to complete one orbit while the outermost planet completes an orbit in 6 days.
TRAPPIST-1d was initially discovered by citizen scientists who identified it from ground-based telescopes.
Transiting systems like this are great targets because you can see the whole event unfold just once per year. And even better, the team didn’t need any space missions to find these planets.
HD 219134 b – A Super-Earth With Carbon Dioxide Lining Its Atmosphere?
In May 2018, astronomers announced the discovery of HD 219134 b, a super-Earth exoplanet located 40 light-years away from Earth in Ophiuchus, a famous constellation. It’s the first time that carbon dioxide has been detected surrounding an alien world.
The research group made use of the well-known High Accuracy Radial Velocity Planet Searcher which is also known as HARPS and is a spectrograph mounted at ESO’s La Silla Observatory in Chile, to study the chemical makeup of the gas giant.
They took advantage of the fact that each planet orbiting a host star will move along a curved path around the star due to gravitational forces.
As a result, the gravity from the other planets pulls on the gas giant causing it to wobble back and forth or rock side to side.
This effect is similar to what happens when you throw a ball into the air, except in this case, it’s billions of times more massive than your average baseball.
To measure the motion caused by the gravitational pull of the other planets, the researchers needed to precisely determine where the star was in the sky. For this purpose, they monitored the amount of heat given off by the star with HARPS.
Kepler-22b – An Alien World With Two Moons
Kepler-22b is a Neptune-sized exoplanet located 1,000 light-years away from Earth. This planet orbits very close to its sun. So much so, that if we were able to travel there, we would only have to go outside for a few minutes before our skin burned up.
However, despite being scorching hot, this exoplanet is not uninhabited. Astronomers recently determined that it harbors two moons: Kepler 22c and 22d.
Kepler 22c measures about 2,200 miles wide, making it larger than Mercury but smaller than Pluto. Although Kepler 22c is likely too small to hold onto enough atmospheric pressure to maintain surface liquid water, it may still contain ice under the surface.
Upsilon Andromeda b – An Exomoon With Water Vapor Clouds
Upsilon Andromeda b is a Neptune-size moon orbiting a distant star in the galaxy known as Messier 83.
The moon was discovered using the Hubble Space Telescope in 2014. The moon has a diameter of approximately 3,700 miles, which makes it slightly bigger than Saturn’s largest moon Titan.
But unlike Saturn’s moon, this moon has no solid surface; instead, it’s covered in thick clouds made of water vapor.
Gliese 832 c – An Alien Moon With Rivers Of Liquid Water On Its Surface
Gliese 832 c is a potentially habitable moon orbiting a red dwarf star. Gliese 832c is thought to be one of the closest worlds to us capable of supporting life. The moon is believed to have rivers of liquid water running down its surface.
We hope after reading this article, you are now convinced that there is a possibility of life beyond earth. There are many different types of exoplanets out there, some of them even look like Earth!
Hopefully, over the next decade or so, we can find these exoplanets and figure out how to get there ourselves!
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