An earth-like planet may actually very well be the discovery of the century as far as the human race is concerned.
Scientists at the European Southern Observatory (ESO) today confirmed the existence of an Earth-like exoplanet which lies in the habitable zone of Proxima Centauri.
Proxima Centauri is the closest neighboring star to our own. The discovery is being hailed as one of the biggest astronomical discoveries of this century.
The details of the discovery were recently published in nature.
This isn’t the first time the scientific community has found earth-like exoplanets (which are basically planets that lie outside of our star system i.e solar system). As of now of, astronomers have been able to discover around 3500 exoplanets.
Very few of these 3500 exoplanets are actually earth-like in their nature. Rumors of the existence of a possible earth-like exoplanet first came into attention on August 12 when a story was published in German weekly Der Spiegel.
Der Spiegel cited an undisclosed source with the La Silla Observatory research teach and claimed that the rumored exoplanet was believed to be an earth-like planet.
The magazine also alleged that the earth-like planet orbited at a suitable distance to Proxima Centauri (basically a low mass star) and hence could have liquid water on its surface.
Liquid water is considered to be an absolutely vital requirement for the development of life on any planet.
Of course, now with this new story, we know that those rumors were authentic. Scientists have indeed found clear evidence for an exoplanet that is orbiting Proxima Centauri.
As mentioned before, Proxima Centauri is a small red dwarf star. It is located about 4.25 light-years away from our solar system.
The Proxima Centauri is marginally closer to Earth than the famous pair of Alpha Centauri A and B.
The new exoplanet, however, is being labeled as “Proxima b”. Observers at the European Southern Observatory has approximated the earth-like exoplanet mass to be around 1.3 times that of the Earth.
The, yet unnamed, earth-like exoplanet has been reported to be orbiting Proxima Centauri at a distance about 4.3 million miles. That distance makes up a total of 5 percent of the distance between Earth and the Sun.
Some might think that since the Earth is known as the “goldilocks planet” since it has the perfect distance from its orbiting star for life to evolve, the much shorter distance between Proxima Centauri and its reported orbiting planet would have no chance of developing any life.
While it is true that the distance between the Earth and the Sun is the ideal distance for life to evolve but the thing we must understand is that Proxima Centauri is not like our Sun.
The Proxima Centauri is much cooler than the Sun our earth is orbiting and hence, scientists have determined, Proxima b is reasonably within the habitable zone for exoplanets.
Researchers have stated that it is likely that Proxima b has sufficient variation with surface temperatures for water to be present in a liquid state on the surface of the exoplanet.
The first exoplanet was discovered in 1995 and since then, as mentioned before, astronomers have been able to identify around 3500 planets that orbit a star other than our Sun.
Pedro Amado of the Instituto de Astrofisica de Andalalucia said during a press conference earlier in the day that humans lived in a universe that was abundant with terrestrial planets.
Scientists now know that Red dwarf stars such as the Proxima Centauri as specifically suited to be overflowing with small, rocky earth-like and earth-sized exoplanets.
Guillem Anglada-Escude of the Queen Mary University of London, who is also the lead author and project coordinator, said that the initial hints of the existence of this new exoplanet appeared sometime in 2013.
She said that back in 2013 there wasn’t enough evidence to support the presence of such exoplanet.
The most recent observation attempt from European Southern Observatory is called Pale Red Dot. The Pale Red Dot name might be a reference to Proxima Centauri since it is a red dwarf star. The campaign named could also have been inspired by Carl Sagan’s “pale blue dot” description of planet Earth.
A team of scientists from eight different countries, totaling to about 31 in number, made use of the Doppler effect to observe a vague wobble in Proxima Centauri’s spectrum of light.
The spectrum of light from Proxima Centauri approached and then moved away from Earth every 11.2 days at around 3 MPH.
The wobble of this sort could have been the result of the gravitational pull of an orbiting planet.
Scientists then continued to combine the data from the Pale Red Dot operation with older data that was collected between 2000 and 2014.
This enabled the astronomers to verify a sharp peak in the Doppler shift data which indicated the existence of an Earth-like exoplanet. In other words, the sharp peak which was well over the threshold for exoplanet discovery allowed the scientists to confirm the existence of the new exoplanet.
The technology to detect and discover exoplanets like Proxima b has been available for the past ten years at the very least. Some readers might legitimately put forward the question as to why it took over a decade for the astronomers to detect proxima b.
Well, the reason for the delay was Proxima Centauri’s activity levels. Proxima Centauri is a very active star when compared to other similarly sized stars. Its native brightness can confuse observers into mistaking it for a potential planet.
This time, the team of researchers banked on the observations that were made with two other telescopes. Researchers then charted how the brightness levels of Proxima Centauri varied over time.
This process enabled them to rule out the possibility of a false positive. According to Anglada Escude, the chance that this new signal is a false positive is about 1 in 10 million.
In other words, researchers are pretty much dead sure that the new signal is that of a planet and not of a dwarf star.
However, the discovery of an earth-like planet isn’t just about ascertaining the exoplanet’s distance from its nearest star. Researchers still are not clear if the new exoplanet, Proxima b, has an atmosphere.
As mentioned before, the Proxima Centauri is an uncommonly active star and as a result, Proxima b has to endure x-ray fluctuations that are approximately 400 times higher than what humans experience on Earth.
This X-ray offense on Proxima b can potentially destroy any atmosphere that Proxima b might have.
Ansgar Reiners, who works at the University of Gottingen in Germany, recently stated that the possibility of an atmosphere or no atmosphere depended on how and when the exoplanet in question was born.
Questions such as where planet originally formed, was it further out than its present location with water present or did it migrate closer to its parent star at a later time. The exoplanet’s proximity to Proxima Centauri at the time of formation is also a question that needs to be answered if researchers are to make sure that Proxima b has an atmosphere.
According to Ansgar, if the researchers at European Southern Observatory can ascertain that the exoplanet was indeed formed further out from Proxima Centauri and had water present at the time of formation and then later moved closer to its parent star then there is a greater chance that the exoplanet may have an atmosphere.
He also said that there were many models and simulations that produced very different results. Some of the possibilities included an atmosphere and the presence of water but a lot of other didn’t.
Reiners also said that researchers currently had little idea about the situation with Proxima b but the existence of an atmosphere was not out of the question.
If Proxima b indeed has an atmosphere than that would indicate positive signs for the existence of life on the newly discovered exoplanet.
Perhaps, the most exciting part of the whole scenario is that Proxima b is relatively very close to our solar system.
So if scientists are able to confirm the existence of an atmosphere and water on the planet than humans may be able to send exploration robots to the exoplanet within a single generation.
Abraham Loeb, who works at Harvard University and also chairs the advisory committee for billionaire Yuri Milner’s Starshot Initiative, told Gizmodo that the lifetime of Proxima was several trillion years which was almost a thousand times longer than the remaining lifetime of our Sun.
He also added that the habitable rocky planets around Proxima Centauri would be the most reasonable location where humans could form a new civilization after the Sun would die about five billion years from now.