Space

Exoplanet with Earth-like temperature discovered nearby – and it's getting closer

Exoplanet with Earth-like temp...
Artist's impression of Ross 128 b, which was discovered orbiting a red dwarf star – the most common type of stellar body in the universe
Artist's impression of Ross 128 b, which was discovered orbiting a red dwarf star – the most common type of stellar body in the universe
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Artist's impression of Ross 128 b, which was discovered orbiting a red dwarf star – the most common type of stellar body in the universe
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Artist's impression of Ross 128 b, which was discovered orbiting a red dwarf star – the most common type of stellar body in the universe
Artist's impression of the view from the surface of Proxima b – Earth's current closest neighboring exoplanet
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Artist's impression of the view from the surface of Proxima b – Earth's current closest neighboring exoplanet

An international team of astronomers has discovered a temperate Earth-sized world with the potential to harbor alien life. The planet, known as Ross 128 b, is located a mere 11 light-years from Earth, and will one day become the closest exoplanet to our Sun, dethroning our current immediate neighbor exoplanet – Proxima b.

Ross 128 b was discovered by researchers using the European Southern Observatory's (ESO) High Accuracy Radial Velocity Planet Searcher (HARPS) located at the La Silla Observatory in Chile. The HARPS instrument, which is mounted aboard a 3.6-meter optical and near-infrared telescope, does not directly observe exoplanets, but instead watches for a minute wobble in the motion of a host star created by the gravitational influence of an orbiting world.

Astronomers are able to use HARPS data to estimate certain characteristics of an exoplanet, such as its mass, orbital period, and distance from its host star. Exoplanets discovered by HARPS can then be examined in further detail by other instruments and observatories, including the ESO's Extremely Large Telescope, which is expected to achieve first light in 2024.

"This discovery is based on more than a decade of HARPS intensive monitoring together with state-of-the-art data reduction and analysis techniques," comments Nicola Astudillo-Defru of the University of Geneva, Switzerland, who co-authored the discovery paper. "Only HARPS has demonstrated such a precision and it remains the best planet hunter of its kind, 15 years after it began operations."

In this case, HARPS spotted evidence for the existence of the newly discovered exoplanet around the red dwarf star Ross 128. Based on the data, the team estimated that the imaginatively-named exoplanet Ross 128 b orbits its star at the equivalent of one twentieth the distance between the Earth and Sun.

Despite its proximity to its star, Ross 128 b only absorbs about 1.38 times as much radiation as our planet, giving the Earth-sized world a hospitable equilibrium temperature in the range of -60 to 20 °C (-76 to 68 °F). This is because the red dwarf is much smaller and cooler than our star.

Artist's impression of the view from the surface of Proxima b – Earth's current closest neighboring exoplanet
Artist's impression of the view from the surface of Proxima b – Earth's current closest neighboring exoplanet

Ross 128 is travelling towards our Sun, which means that Ross 128 b will unseat Proxima b to become Earth's closest exoplanet neighbor in just 79,000 years. The discovery of Proxima b was announced in August 2016 to huge excitement, but there are serious doubts regarding its potential habitability that stems from the nature of its red dwarf parent star, Proxima Centauri.

Whilst red dwarfs are by their nature significantly dimmer and smaller than Sun-like stars, they still have the capacity to emit powerful solar flares that bathe orbiting exoplanets in ultraviolet and X-ray radiation. This onslaught of radiation can strip a nearby world of its atmosphere, essentially causing it to be slowly lost to space. Without this protective shield, an exoplanet would be at the mercy of the radiation pouring from its star.

This is one of the reasons that Proxima b could be inhospitable to the evolution of extraterrestrial life. Ross 128 on the other hand is thought to be relatively inactive, and so may not pose as great a threat to Ross 128 b as Proxima Centauri does to Proxima b.

Ross 128 b has many of the hallmarks that make for a promising target in the search for extraterrestrial life as it shares many similarities to Earth, the only world on which life is known to exist.

There is however a major question mark over the habitability of the exoplanet. The team behind the new discovery is not certain that Ross 128 b orbits within the habitable zone of its star – the region of space in which a planet receives the correct amount of radiation to allow liquid water to exist on its surface.

The presence of liquid water on ancient Earth is considered to be one of the cornerstones of the evolution of life on our planet, and so if Ross 128 b were unable to host liquid water on its surface, it would be damning to the exoplanet's chances of hosting life.

Astronomers are planning to use cutting-edge, next-generation observatories to search for evidence of biological life in the atmospheres of select Earth-sized, temperate exoplanets orbiting red dwarf stars.

A paper detailing the discovery of Ross 128 b has been published in Astronomy & Astrophysics.

Source: ESO

10 comments
VincentWolf
Space travel to distant planets won't happen for tens of thousands of years. And that's a good thing because mankind needs to evolve and rid itself of it's violent and greedy tendencies before exporting that to other systems.
Bob
I keep wondering when people will wake up to the fact that space travel involves huge distances, extremely long travel times and fatal cosmic radiation. In other words space travel will always be a fantasy. What element or resource is even worth a one way fatal trip to the nearby planet Mars? No matter how many planets we find outside of our solar system, the odds of finding a habitable one are very small. The odds of traveling there are even smaller.
Riaanh
@Bob, the element which makes it all worthwhile is called "survival" Only by becoming a space travelling species can we ensure the survival of our species. We are so much more technologically advanced than the dinosaurs, but a major meteorite strike could just as effectively be our end as well. But I have no doubt that none of the scientists invloved in the pursuit of habitable planets are even entertaining a thought of anybody going there, they are doing it as part of our general quest for scientific knowledge, and to answer the burning question as to whether we are alone or not.
Nik
I think Bob's pessimism regarding space flight is rather extreme. Given sufficient power, an electromagnetic protective shield could be set up to deflect radiation, and protect a crafts occupants. The craft would need to be a 'space city,' as the distances involved would mean extended travel times. It would probably be more like a military air base, with all the required facilities and materials stored on board, plus the option to 'mine' any passing stray body for anything useful. It would also need an intensive farming system to grow fresh food, and recycle all wastes. Given time, say within 1000 years, the time problem may also be solved, if the changes over the last 100 years are considered, ie. from horse drawn vehicles being the main transport, to the present approaching 'all electric' transport, and emerging space travel.
RobertEhresman
Personally, I believe we will solve FTL in less than 200 years. Hydrogen fusion power in considerably less than that, maybe matter/antimatter power too and we will go where ever we wish within this arm of the Milkyway Galaxy. I also predict that some folk alive to day will live to see it. All predicated on not loosing our existence or humanity to something like a robot apocalypse.
Helios
@Bob I agree completely. To add to your comment, I keep wondering if Stephen Hawking is finally starting to slip mentally or if he is just making sport of the ignorant masses or maybe he just likes being a showman. But his comments are both reckless and absurd. Pinning humanity's hopes on finding a habitable planet ONLY nine light years away...
Bob
Obviously, some thought my comment was pessimistic rather than realistic. But just consider the logistics of an 80 year trip to another planet. What is the smallest viable crew for survival? 160 men and women or 50 women plus a sperm bank? What fields of expertise would be required during the trip and after landing on another planet. How often would the crew have to reproduce during the trip and train the children. How many hundred additional people born would have to be supported on the ship during the journey? What power supply could power the ship and start a new civilization? Besides shielding against cosmic radiation what will shield against small meteors or even dust during such a long trip? How many ships would have to be launched to assure that even one succeeds in making the journey. What happens if there are no concentrated sources of fuels or resources on the new planet? How will we know for sure if the target planet could even support our form of life? If you are concerned about a meteor destroying earth which can and does absorb thousands daily, what happens if a rock the size of a baseball or even a small marble hits your spaceship at over 50 million mph?
ljaques
Vince is right: we need to overcome greed and violence before we leave this planet for exploration. It might help if we develop fusion, warp, and gravity drives first, too. C'mon, SciFi writers. Develop these concepts further and give them to scientists to make 'em real! I don't think it will take 10 millennia, either. Heck, at the rate we started going in 2016, the few who are left after the nasty civil wars should evolve rapidly into a meeker crew which could be spaceworthy in less than a century. Pray for that, folks. Send our great-grandkids out to the stars!
IvanWashington
before we can run to another planet, we first have to outrun fatally flawed human nature. i'm not holding my breath on this to happen, ever.
toyhouse
I remember the same arguments decades ago in college. One group says, we have no moral right to travel the cosmos until we evolve. And that means, we have to stay here to do it. Another group says, a defining trait of humanity and part of our evolution,...is to explore. That's how we evolve. Another says, the rules of physics are set in stone. The technical challenges of traveling the cosmos, insurmountable. It'll take millennia if at all. I remember so many of those arguments. Out of it, one thing became clear - one group will always have to know the answers to really big questions. You can't stop them even if you wanted to. But why would you anyway? Personally, I've always rooted for the underdog.