Why Earth-Friendly Planet Proxima B is Actually Different from Our Planet
A possible Earth-like planet found near our galaxy called Proxima Centauri b has been discovered only four light-years away. Despite experts saying that it's Earth-friendly, there is, in fact, a lot of difference between Proxima b and our planet.
Out of 3,375 exoplanets that are discovered since 1989, there are only 10 planets that are deemed potentially habitable. Why is that so? It is possible that despite having sophisticated and advanced equipment, the technology we use today still has its limitations. This means that we cannot fully tell if such planet is indeed habitable. The techniques that we used can also be biased.
Ways to Find Stars
Methods have always been used by scientists to find a star and its possible planet. One of these methods is transit, where scientists measure the brightness of a star they are monitoring. They wait for the star to dim while a planet passes in front of it, Five Thirty Eight reports. Accompanying this method is the use of Kepler, the most known space-based telescope, which can spot 20,000 stars and their brightness all at the same time.
Meanwhile, radial velocity doesn't rely on pure "geometric" line-up. Scientists who use this method study the spectrum of light. Here, they look out for changes in the spectrum made by the interactions that occur between the gravity of star and the gravity of its nearby planet. Doppler is used for this method. Though it doesn't find a lot of planets compared to the transit method because it can't study far-away stars, radial velocity is more precise and it can find planets not detected via transit.
However both methods can still miss out other classes of planets according to Gibor Basri, professor emeritus of astronomy at the University of California, Berkeley
Finding the density of a planet is significant because this will really tell if a planet is habitable or not. Transit can determine radius of a planet while radial velocity can know the mass. Both transit and radial velocity methods cannot determine a planet's density; thus, the limitations. To get the calculations of density, we need to know the radius and mass of a planet. Density can segregate planets from habitable and not. It can also tell if a planet is rocky or is full of gas.
Earth vs Proxima b
Proxima b is discovered using radial velocity. Despite being more specific, it is still early to tell if it is habitable, especially now. According to Forbes report, there are actually a lot differences between Earth and Proxima b. If Earth has Sun, Proxima b has Proxima Centauri, and it appears larger in the planet than our Sun due to its close proximity.
An Earth year means 365 days, but in Proxima b, a year means 11 days. Climate zones in Proxima b is a bit strange because on the side facing away from its star is eternally night while the other side facing the star has forever daytime. Meanwhile, the ring' part of the planet has an "eternal dawn/sunset."
Solar flares in the day side of Proxima b is dangerous and cancerous to any life forms, unlike Earth that has a magnetic field to protect living things from solar flares. Meanwhile, winds in Proxima b drift from the day sode to the night side while Earth has encircling winds.
When you are in Proxima b, you'll get to see two bright stars, Alpha Centauri A and Alpha Centauri b, which are even brighter by 140 and 30 times than our brightest star, Sirius.
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