Gliese 436b: Why does this exoplanet have hot ice?
Have you ever gazed up at the night sky and wondered if there are planets outside the solar system? Well, there are many of them and they orbit a star outside the solar system. Astronomers call them exoplanets. One exoplanet that has captured the attention of astronomers and space enthusiasts is the Gliese 436b, sometimes called GJ 436b, located 30 light years away from the Earth. This distant world, discovered in 2004, is one of a kind. It has a unique atmosphere and a mysterious composition that has scientists puzzled. Do you want to know what quality makes it strange? It is a place where ice can burn! Curious? Buckle up, and let's take you on a journey through this exoplanet and discover why it's such a special place in the universe!
What is an exoplanet?
An exoplanet is a planet that moves around a star outside our solar system in the darker region of our galaxy Milky Way. Just like Earth orbits the sun, exoplanets orbit other stars. These planets are so far from us that we can't see them with our eyes. But we have special tools and techniques that allow us to study them and learn about their size, orbit, and atmosphere. To put it simply, imagine living in a big house with your family where the sun is like your house's lamp, and Earth is your room. The exoplanets are like other rooms in other houses far, far away. Just like you can't go to those rooms, we can't visit exoplanets, but we can learn about them for sure by observing them from a distance.
Meet Gliese 436b
American astronomers R. Paul Butler (from the Carnegie Institute of Washington) and Geoffrey Marcy (from the University of California, Berkeley) made a ground-breaking discovery with the Neptune-sized exoplanet Gliese 436b in 2004. It orbits around a red dwarf star called GJ 436, located in a constellation named Leo, housed in the Northern celestial hemisphere. This is why it is also referred as GJ 436b. Can you guess the time Gliese 436b takes to orbit? Just 2 days! In addition, this exoplanet is located very close to its star. To put things in perspective, it’s just 1/13th of the distance between mercury and the sun and mercury is the closest planet to the sun! Due to its proximity to its star, Gliese 436b is like a scorching ball with temperatures reaching up to 526ºC.
Decoding the mystery of hot ice!
Gliese 436b is an odd planet that defies all expectations. Our solar system's gas planets, such as Neptune, Saturn, Uranus and Jupiter, are composed of gas (mainly hydrogen and helium). Gliese 436b is similar in size to Neptune but is too compact to have a complete hydrogen makeup. However, it is not compact enough to be considered a rocky planet like Earth. So, what exactly is it made of? This celestial gem houses a secret treasure trove of 'Ice-x,' an exotic form of water-ice. This strange substance stays solid even in scorching temperatures that could melt your face off! But how, you ask? The planet's immense gravity compresses the water vapour in its atmosphere, keeping it in its solid form. So, gravity is the reason for keeping the water in its solid stage!
The methane mystery
There is one ingredient common to all planets in our solar system, methane. Planets with a temperature of over 500ºC have more methane and a small amount of carbon monoxide. However, NASA's Spitzer Space Telescope found no evidence of methane and a large amount of carbon monoxide on Gliese 436b! The reason for this reverse character is still unclear and the mystery of missing methane continues to perplex astronomers!
We can say one thing for sure, there is still a lot to uncover about this strange and amazing planet, Gliese 436b!