Monday Bites: Ad Astra

 Monday Bites: Ad Astra 

Credit: ESO/M.Kornmesser

A light year is the distance traveled by light itself cruising at its maximum permissible speed of 300,000 km/s or 186,000 miles/s in one year. Discarding all theories and technological limitations, even if we could travel at light speed, a round trip to the nearest star, Proxima Centauri, 4.25 light-years away, a mere stone's throw away, demands eight-and-a-half long years in the unforgiving seclusion of cold, dark interstellar space. 

Our Sun is one lonely star among a hundred billion or more bright stars and dim stars, young hot ones, cooling red dwarf ones, and some more arranged in a spiral known as the Milky Way galaxy. And how many galaxies are there? Anywhere between 200 billion to over one trillion, each home to a hundred billion or more stars. Within the galaxy, the Sun is almost lost. It's just a tiny dim dot among a few million of its cousins and siblings forming a bridge, a spur, between the two spiral arms, the Sagittarius and the Perseus. 

Going at the speed of Voyager 1, the fastest spacecraft we've built so far, at 62,000 km/h or 38,500 miles/h, i.e., going at 0.056% of the speed of light, it would still take over an absurd 73,000 years to reach our nearest neighbor. We can always send a probe out of the solar system. But as it goes further, apart from the signals getting weaker, the radio-thermal generators would eventually fail and leave the probe useless. So, our current technology restricts spacefaring to the Moon only.

However, that doesn't mean we aren't allowed to think of going to the great beyond. In the distant future, if we could attain the technology — how are we going to do that is an outstanding intellectual exercise, assuming we do — then Proxima Centauri or rather Alpha Centauri will be the first star we visit, and Proxima Centauri b, the first exoplanet we land on. 

So far, we know that Proxima b, a rocky planet, lies within the Habitable or Goldilocks Zone of its parent star, a red dwarf. The habitable zone refers to the region around a star where water is able to exist in its liquid form. What you see here is an artist's impression of what it might be to stand upon exoplanetary soil. The bright red star low on the horizon is Proxima Centauri, and the binary Alpha Centauri system rises in the distance.