What happens if our SUN has an evil twin in our Solar System? The topic has been very well explained in the ‘Nemesis Theory’.

Nemesis, the theoretical second sun in the solar system, is a dwarf star named after the Greek goddess of vengeance. In English vocabulary, the word Nemesis means doom or ruin, and certainly, nothing good can come from a celestial body with that name.

Nemesis theory supporters say it has happened before. In fact, every 26 to 28 million years the Earth has a small problem. A terrible and mysterious cataclysm is causing a mass extinction, destroying most of life on Earth and altering the balance of nature.

This was a purely theoretical question for a long time. However, in the past decade, astronomers have discovered more than a dozen confirmed cases of "marginal planets," planets orbiting nearby binary stars.

A particularly interesting case is the planet Kepler 1647b, which orbits two stars close to the Sun. Additionally, this planet falls within the "habitable zone". This is the region around the two stars where the planet may be at a suitable temperature for liquid water.

What if the earth had two suns instead of one? Consider a simple scenario. Suppose we replace the Sun with two stars, each about half as bright as the Sun. In that case, the amount of energy reaching Earth would be unchanged, and life here would still be possible. Such double stars of equal mass are not uncommon, so this scenario seems very plausible.

Each of the new Suns (I call them Sun 1 and Sun 2) will have about 85% of the mass of the Sun today. This may seem surprising, but the luminosity of stars is very mass-sensitive. Roughly speaking, luminosity is the fourth power of mass, so doubling the mass of a star makes it 16 times brighter (2x2x2x2). A 15% reduction in mass is enough to halve the brightness of a star.

The combined mass of Sun 1 and Sun 2 is 1.7 times the mass of the Sun today. Due to the stronger overall gravity, the year is slightly shorter, about 280 days instead of 365. It's actually not that dramatic of a change.

So far so good. But will the Earth stabilize in a new configuration that orbits two stars instead of one? In the case of Kepler 1647b and other circumbinary, the answer here is a resounding yes. As long as the distance to the planet is at least about four times the distance between its two stars, the planet will happily orbit the star's centre of mass. All planets in the solar system (including Mercury) are potentially stable if the distance between Sun 1 and Sun 2 is less than 15 million km.

Sure, let's bring the stars closer together. About 5 million kilometers away. That's not much different than the two stars of Kepler-1647, which are about 7 million miles apart. Our Sun 1 and Sun 2 orbit each other about once every 10 days. Each will also rotate in its 10-day cycle, making it slightly more active than the Sun today, but not prohibitively. The Kepler 1647 star is moderately peaceful.

The two suns will likely orbit each other almost end-to-end as seen from Earth, giving rise to the strange new phenomenon of an eclipse by another sun. Since the orbital period is 10 days, Sun 1 and Sun 2 pass each other every 5 days. The eclipse lasts about 6 hours and at its peak reduces the amount of energy reaching Earth by about 30-40%, depending on its exact shape.

The eclipse will be cooler, but the period of low sunshine will be short enough to fit seamlessly into the Earth's overall climate. The twin suns don't look all that strange in the sky either. At maximum separation, Sun 1 and Sun 2 are only 2 degrees apart in the sky, enough to give shadows a double edge. For about half a day they seemed to coalesce on either side of the eclipse, but when they slipped behind the clouds, a strange oval shape was visible from the overlapping discs. The sunset must be beautiful, every night is a little different.

So all the evidence so far suggests that planets like Star Wars' Tatooine could actually exist and that if Earth orbited a binary star instead of the only Sun, Earth would function just fine. There is only one big unanswered question. Is it possible for such a planet to form?

Kepler-1647b is a gas giant with nearly twice the mass of Jupiter. Even the smallest known circumbinary, Kepler 453b, is larger and more massive than Neptune.

Binary environments are too chaotic to form small rocky planets like Earth. On the other hand, it's possible that other Earths with two suns are common and our telescopes aren't sensitive enough to find them. At least not yet.

Fortunately, better equipment is coming soon. In the next decade, the PLATO Space Telescope and gigantic new ground observatories such as the Giant Magellan Telescope and the Extremely Large Telescope will tell us more about all kinds of planets around other stars. in their skies.