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What Would It Look Like If You Replaced the Sun with Other Stars?

When humanity finds a new exoplanet or releases new images of a distant star, we are compelled to imagine what it would look like to live around it. Russia’s space agency Roscosmos has just made that possible. In two lovely videos, Roscosmos replaced our Sun and Moon with other stars and planets. The results are gorgeous, but they would also destroy the Earth. 

The video putting us in orbit around other stars has some interesting implications for our planet. First the Sun is replaced with Alpha Centauri. The closest star to Earth, the Alpha Centauri system sits about 4.22 light years away from us and is actually a binary system — Alpha Centauri A and B are gravitationally locked to one another with a third star, Proxima, nearby.

We know planets exist around binary systems, but if we orbited this binary system the planet probably wouldn’t be Earthlike. Alpha Centauri A is cooler than the Sun but 1.6 times as bright while Alpha Centauri B is only about half as bright as the Sun.

The Sun is also replaced by Sirius in the video, which is the brightest star in our sky. About 8.6 light years from the Earth, Sirius is about 7,000 degrees Fahrenheit hotter than our Sun (which is about 10,000 degrees Fahrenheit). It’s also more than twice the mass, and just less than twice the diameter. But most significantly, Sirius puts out 26 times more energy than our star.

And what about replacing the Sun with Arcturus, the red giant roughly 25 times the size of our star? Because it’s so massive, Arcturus radiates more than 100 times the visible light of our Sun. And if you take all the other kinds of radiation into consideration, Arcturus is about 200 times more powerful.

Vega, the last star that replaces our Sun in the Roscosmos video, is nearly 17,000 degrees Fahrenheit like Sirius and 2.5 times the diameter of our star. And Vega actually burns its fuel faster, producing 35-40 times the energy of the Sun.

Each of these stars, or star system in Alpha Centauri’s case, puts out more heat, energy and radiation than the Sun. The Earth as we know it would unlikely have evolved orbiting any of these stars. So while it might be an interesting visualization, the reality would probably be a scorched, lifeless Earth more like super-hot Venus or even atmosphereless Mercury.

As for replacing our Moon with planets, the views might be spectacular but this would also have stopped the Earth from becoming the planet we know and love. The gravitational pull of any of the gas giants — Jupiter, Saturn, Uranus, or Neptune — orbiting just quarter of a million miles away would definitely pull our little planet into another orbit or possibly apart. These changes could have prevented Earth from coalescing into a planet to begin with. Not to mention the light reflecting off these massive planets as moons would make for very bright nights, drastically affecting the kinds of life forms that would develop on our planet, if it was able to exist. We might survive with terrestrial planets orbiting closer to home, though again these bodies would take their toll.

So while it might be fun to imagine life on a planet orbiting a binary star system with Saturn hanging large in the night sky, it’s probably best we have the Sun and Moon we do.

IMAGE: Roscosmos/You Tube

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  1. Mike says:

    7000°F is not equal to 10000°F. I’m an engineer. I know these things