When you look at the nighttime sky, you see thousands of stars shining, as the light that left them years ago, finishes its travel and reaches your eyes. Each one of those stars is comparable in size, to our Sun, with some even having planetary systems encircling them. One can't help but wonder which is the closest star to our solar system, other than the Sun. All the stars that you see, belong to our own Milky way galaxy, which is an island of matter and energy, in the vast emptiness of space. Which one among these thousands of stars is nearest to us? To find out, keep reading ahead, as I reveal it to you, in case you are planning a destination for interstellar travel.
Closest Star - Proxima Centauri
The nearest star to Earth, with the obvious exception of the Sun, is 'Proxima Centauri'. Stellar distances are measured in light years. A light year is the distance traveled by a ray of light for one Earth year (for the record, nothing travels faster than light). So, if you calculate, by multiplying the speed of light in meters per second (approximately 3 x 108 m/s) by the total seconds in a year, one light year turns out to be about 10 trillion kilometers, that is 1016 meters.
So, getting back to the point, the nearest star to the Earth, Proxima Centauri, is about 4.243 light years or 3.97 x 1013 km away from us. That is too many zeroes. So, a ray of light leaving Proxima Centauri will take 4.243 Earth years to reach us. Another way of getting an idea about the distance is comparing it with the fact that light from the Sun, only takes 8.3 minutes to reach us. That makes it 270,000 times more distant than our Sun.
Aptly named with the prefix 'Proxima', meaning 'nearest to' in Latin, it was discovered by Robert Innes, looking at it from the Union Observatory in Johannesburg, South Africa, in 1915.
To locate Proxima Centauri, you must first locate the constellation Centaurus, in which it is located. Two interesting facts about the star are that it is a 'Red Dwarf Star' and also a flare star, while possessing mass which is one eight of our own Sun.
It is cooler at the surface than our Sun (with a temperature of about 4,000 Kelvin) and is still in the main sequence stage of evolution of stars. Though, it's less massive than the Sun, its density is 40 times more. The reason it is called a 'Flare Star' is its volatile brightness, which keeps on waxing and waning with the activity of its magnetic field. No planets have been discovered orbiting it so far. Also, its nature being that of a flare star, largely rules out the possibility of life arising on any planets surrounding it.
The star is suspected to be gravitationally bound to the Alpha Centauri (Twin Star) system, which is about 0.21 light years away. In about 26,700 years in the future, Proxima Centauri will come even more closer at just 3.11 light years away from Earth and then move away.
The second nearest star to Earth, other than Sun, is Alpha Centauri. As mentioned before, it is a binary star (two stars revolving around each other) and located at a distance of 4.37 light years. This makes the dual star system to be the second nearest to Earth and the second closest destination for interstellar travel. It is the brightest star in the Centaurus constellation and the third brightest object in the night sky.
One day, there will be a human spaceship orbiting Proxima Centauri and who knows what we will find there. Our descendants may truly live among the stars one day. Once interstellar space travel is made possible, even the sky won't be the limit, for the human race.