In August, scientists made a major discovery in their search for extra-terrestrial life, a potentially habitable planet orbiting our nearest neighbouring star.
For a planet to be considered habitable, it must be within the Goldilocks zone of its star. This is the area where the planet isn’t so close to the star that its water evaporates, but not so far away that it freezes. This is the most important factor when looking for life on other planets as it is believed that all life requires water to survive. Even if alien life is not found, finding liquid water alone would be a major advancement, as Earth is the only planet currently known to hold liquid water.
If we wanted to actually live on such a planet, it would also need to be a similar size to Earth. Bigger planets have stronger gravity and vice versa, so if the planet is smaller than Earth, there would be less gravity and we would have to find ways to weigh ourselves down so we don’t float around like astronauts on the moon. If the planet was much bigger than Earth, we would feel like we were being constantly weighed down, which could have a negative impact on our health.
These specific conditions mean that it’s very rare to find a planet that could hold life, or that we could live on without spacesuits and airlocks. Even when we do find promising planets, they are too far away to be explored in the next century. However, it’s possible that such a planet has been sitting just 4.2 light years away this entire time.
The closest star to our sun, Proxima Centauri, was discovered in 1915, but its planet Proxima b was only confirmed on August 24th this year. A planet orbiting Proxima Centauri has been theorised for the past few decades, but more advanced technology and a great deal of patience were required to actually detect it. The team at Queen Mary University of London that confirmed the planet’s existence had to observe the star every night for over ten weeks to collect enough data to prove that the planet existed.
Until Proxima b’s discovery, the closest known planet to earth was Wolf 1061b, but it is too close to its sun to be considered habitable. Various projects such as the Kepler Space Observatory have been searching for exoplanets (planets outside our solar system) for many years and will continue to in the future.
Other projects have also recently been announced to aid the search for extra-terrestrial life, such as the 100 million dollar Breakthough Starshot project, which aims to develop a nanosized probe that can travel at 20% the speed of light to gather data from exoplanets. Due to the recent confirmation of Proxima b, it will now be the probe’s first destination. The probe will take around 50-100 years to travel to Proxima b (depending on the technology available) but will be able to send information and photographs back within four years.
As life is seemingly only found under very specific conditions, and the data from Proxima b is still very limited, whether or not it will actually contain life is disputed. Either way, its discovery alone is a major step forward for scientists, and further investigation will help us develop a much greater understanding of our solar system.
Jessie Brown is a college student currently studying Maths, Further Maths, and Physics. She has an interest in space and plans to become an astrophysicist.