Many of us have had the curiosity of thinking about what lies outside the world of ours. Mostly we were intrigued by looking up at the stars and wondering how far they are from us. I am not sure about you. But as a child, I have certainly thought about them. The Habitable Exoplanets, aliens, and do they look back at us when we look at their planets?
Although, now I am not afraid of the aliens dominating Earth and steal our food and water. But I am indeed still unsure if they do not exist at all. To suffice to my curiosity of looking beyond this Earth, I introduced myself with the use of a telescope.
Thus, my quest to look for the aliens and if they exist or not – changed into something more valuable and exciting.
Ask me, and I will say – Astronomy is life!
Now let’s focus on whether the other planets and the inhabitants of these planets (if there are any) can see us. We can find out the presence of the other exoplanets via the Transit Method.
What is the Transit Method?
TESS – the acronym for Transiting Exoplanet Survey Satellite was launched in 2018. This satellite’s primary purpose was to analyze the millions of stars we have in the sky – and the number of Habitable Exoplanets orbiting them.
It does so by employing the Transit method – it looks for a slight decrease in the brightness of a star (like the Sun) when a planet orbits it. When the planet passes from the front of the star, its light reaching the Earth or more precisely viewable from the Earth decreases to some extent. You can consider it as a phenomenon somewhat similar to an eclipse.
But does the Earth also appear as an Exoplanet to the stars out there?
A simple answer to this question would be – a yes!
As the Earth continuously orbits the Sun in the form of an ellipse, and the Sun moves around the sky in an imaginary line that we call the ecliptic. The ecliptic marks the projection of Earth’s orbit into space. Those who are fond of stargazing – they are well aware of this jargon.
Thus, any stars that are close to the ecliptic can see the Earth transiting the Sun once a year – a light year to be precise.
Search for Extraterrestrial Intelligence (SETI)
Many people are involved in the Search for Extraterrestrial Intelligence (SETI) to look for planets that can sustain life. With the increasing population, there is pressure on the Astronomers as well – to find out the planets like Earth that can support life.
Even if we find such a Habitable Exoplanet, we need to know if there are individual inhabitants on it. According to some researches, the planets out there are not entirely abandoned. Hence, we can say that at some time, we will have to negotiate with them.
How to Find Habitable Exoplanets from Earth?
Firstly, you have to figure out how far you can see the Earth transiting the Sun? According to trigonometry – the answer is about one-fourth part of a degree centered on the ecliptic.
The first exoplanet was discovered in 1995 – and it was named 51 Pegasi b. It is a giant planet orbiting around it’s own sun-like star. It is some around 50 light-years away in the constellation of Pegasus. It’s orbital velocity is not more than 102 hours.
To your surprise, today, we have confirmed around 4000 exoplanets. Most of these planets are discovered by the Kepler Space Telescope, which was launched in 2009.
Kepler Space Telescope
The mission of the Kepler Telescope was to find the number of planets that orbit the stars in a specific part of the sky.
However, the ultimate purpose of it was to find places where life was possible to sustain human life in case we run short of food or space on Earth.
After many years of research with Kepler Space Telescope, the astronomers were able to come up with results that there are many more planets in the universe, and surprisingly, there are many more stars too.
What Makes a Planet Habitable?
If you think that life is possible on all those planets out there – then you are wrong! It has to be in a star’s habitable zone where it is neither too hot nor too cold for a place to be survivable.
Hence, there are at least 25 billion places in our Milky Way around a minimum of 100 billion stars where life can take hold.
Seeing inside the Exoplanets
Astronomers have discovered thousands of exoplanets, but most of them are a mystery as yet. All we know about them are their sizes and masses. However, due to scientists and astronomers’ untiring efforts, the field of astronomy has come up with a radio telescope that can actually reveal what lies inside those exoplanets.
This new telescope is so developed that it can detect radio signals coming from a magnetic field. In this way, we can find out if the planet’s core is made up of the same magnetic material as the Earth.
The Radio Telescope is helping scientists find out the chemistry and formation of the six planets and whether they are identical to all planets of our solar system.
It can also detect the habitability of a certain planet by detecting its magnetic field. It is possible because the magnetic fields are able to prevent particles from disturbing the life-possible atmosphere on a planet.
Whether there are any aliens out there or are they going to attack us still remains a mystery, but there is much other ground where we are finally getting some success. With every new research and development, we are one step closer to finding Habitable Exoplanets outside the Earth.
The discovery of new telescopes has made it possible to look far up and deep into the sky and other galaxies.
We now have Kepler telescope, Hubble telescope, Radio telescope, and many others. Hence, we are not bound to see with reflective and refractive telescopes.