Extrasolar Planets
Many people have had interest in outer space and the mysteries that prevail. The idea of finding something that has never been seen is truly exciting. Many have sat in the yard and looked up to the heavens star gazing hoping to find something significant and intriguing that would or could bring about world change. Maybe we would even find a planet that was comparable to ours and could house mankind as we understand it now. We are going to take a look at extrasolar planets. What does the term exoplanet mean? An extrasolar planet is a planet that revolves around a star other than the Sun.
Now, let us take a look at two particular types of extrasolar planets: Gas Giants and Water Worlds.
Gas Giants
The term gas giant is a familiar term as it refers to our large planets that revolve around the Sun beyond the Asteroid Belt. These planets are also known as our Jovian planets because of their similarity to Jupiter (Jove is the old Roman name for Jupiter) Just like our Jupiter, these planets have Hydrogen (H) and Helium (He) in their atmospheres. Many revolve very close to their stars, which makes them hot and hence the term “Hot Jupiter.”
Water Worlds
This term refers to the exoplanet that is covered with water. Unlike the Earth, where only 0.02% of the mass is water, the mass of these planets can be 25%-50% or even more water. These planets are called Hycean planets. These planets are larger than Earth and can possibly be habitable. Hycean planets are hot, ocean-covered and with hydrogen-rich atmospheres, with temperatures reaching up to 392 degrees Fahrenheit (200 degrees Celsius) and are basically water worlds, says Dr. Nikku Madhusudhan the lead author on University of Cambridge’s research9. These planets are described as having hydrogen rich atmospheres coupled with rocky cores. Life, if any, on these planets may be aquatic life because of the amount of water there.
There are smaller frozen water worlds in our solar system, and astrobiologists are looking closely at these moons: Callisto, Enceladus, Ganymede, Europa and Titan for signs of life.” (See table 4 below)”
Table 4: Some interesting Solar System Moons and their Properties
| Moon | Planet | Properties |
|
Europa |
Jupiter |
Possible subsurface ocean.Diameter 3120 km Tidal flexing which may create heat. Possible life through chemical reactions: oxygen. Photosynthesis unlikely |
|
Enceladus |
Saturn |
May have liquid water (ice) |
|
Callisto |
Jupiter |
May have a subsurface ocean |
|
Ganymede |
Jupiter |
May have a magnetic field, possible ice and subterranean oceans |
|
Titan |
Neptune |
Possible liquid water or a subsurface ocean |
Credit: https://www.sciencefocus.com
Source: Amy Godfrey
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