In its exoplanet archive, NASA found proof of the cosmic milestone.
Galileo changed the way people thought about the universe when he realized that Earth wasn’t the center of the universe and that our world orbited the Sun. This proved that Nicolaus Copernicus’ theory from the 1500s was right.
A hundred years ago, astronomers thought that the Milky Way was the whole universe. Edwin Hubble wasn’t able to measure the distance to a star in what would become the Andromeda galaxy until 1925. It wasn’t until then that people realized that our “universe” is just one galaxy in a cosmic ocean.
And in 1995, astronomers found the first exoplanet orbiting another Sun-like star in the Milky Way. This made it clear that our solar system is not the only one like it.
A few decades later, scientists have found evidence of more than 5,000 exoplanets in our galaxy. On March 21, 65 new exoplanets were added to the NASA Exoplanet Archive, setting a new record. The archive keeps track of exoplanet discoveries that have been written up in peer-reviewed papers. They are marked as “confirmed” when they are found or checked with more than one method.
In a press release, the archive’s science lead, Jessie Christiansen, said, “It’s not just a number.” “Each of them is a brand-new planet or world. I’m interested in all of them because we don’t know much about them.
Stranger and stranger
NASA also keeps track of the types of exoplanets that are found. About 35% of the worlds in the archive are like Neptune, which means they are about the same size as the ice giants in our solar system. But these worlds may orbit much closer to their stars than Neptune does, making them “warm.” About 31% of planets are bigger than Earth, and another 30% are gas giants like Jupiter. The last 4 percent are small worlds with a lot of rocks.
But even though exoplanets are often compared to the worlds in our own neighborhood, our galaxy is full of strange planets. These bodies are definitely unique:
WASP-76 b
In 2013, the Very Large Telescope (VLT) at the European Southern Observatory looked at an alien planet called WASP-76 b. This exoplanet is about 640 light-years away and is tidally locked to its star. This means that one side of the planet is always in the sun and the other is always in the dark. On the dayside, temperatures reach over 4,300 degrees Fahrenheit (2,400 degrees Celsius), while the nightside is a cool 2,700 degrees F. (1,500 C).
And the big difference in temperatures makes the weather on WASP-76 b weird. On the dayside, it is so hot that even metals, like iron, can evaporate. The temperature difference is thought to cause strong winds that carry the iron vapor to the nightside, where it condenses and rains down to the surface.
WASP-12 b
WASP-12 b will not end up like most of the other planets on this list. This exoplanet is about 1,400 light-years away. It circles its host star at a distance of only 2.1 million miles (3.5 million km), which is so close that the sun is tearing the world apart. This gas giant has the shape of an egg because of the huge tides caused by the star’s gravity. Astronomers think that the star will eat all of the planet’s life in just 10 million years.
TrES-2 b
TrES-2 b, the “planet of eternal night,” has the darkest skies in the known universe.
This alien world is only 1.5 times as big as Jupiter, and it reflects less than 1% of the light that hits it. This makes it darker than coal. This world is the darkest place in our solar system. But because its atmosphere is as hot as lava, some scientists think a red glow might shine through the darkness, which would be a scary sight for anyone who happened to be there at the time.
Gliese 436 b
On Earth, ice means it is cold, but on Gliese 436 b, where temperatures can reach almost 1,000 F (540 C), ice burns.
Because it is about the same size as Neptune, Gliese 436 b has kept its atmosphere even though it is only 2.5 million miles (4 million km) from its star. But the same gravity that helps it keep its atmosphere also creates enough pressure to turn water into a solid state, even though the world is very hot. This is similar to how carbon turns into a diamond when it is put under enough pressure. But this new solid form of water is probably going to be very different from the ice we know on Earth.
PSR B1620–26 b
PSR B1620–26 b is the oldest known planet in the Milky Way. It goes around a pair of dead stars. For a world that is 13 billion years old, making it through the deaths of not just one but two stars is a big deal. And since the world is so old, it shows that the first planets probably formed soon after the Big Bang, maybe even within the first billion years.
These are just a few of the weird places in the universe. NASA has confirmed 5,000 exoplanets, but there are still 6,000 candidates in the Exoplanet Archive that need to be confirmed. And with an estimated 100 billion exoplanets just in the Milky Way, there will be a lot more to find in the coming decades.