Space

Newfound super-Earth represents an excellent hunting spot for E.T.

Newfound super-Earth represent...
Artists impression of LHS 1140b orbiting its star
Artists impression of LHS 1140b orbiting its star
View 2 Images
Artists impression of LHS 1140b orbiting its star
1/2
Artists impression of LHS 1140b orbiting its star
It is estimated that the roughly five-billion-year-old exoplanet orbits its star once every 25 Earth days
2/2
It is estimated that the roughly five-billion-year-old exoplanet orbits its star once every 25 Earth days

An international team of scientists has announced the discovery of a new "super-Earth" exoplanet (a planet with more mass than Earth, but not quite as big as our gas giants) that could represent our best chance of finding life outside of our solar system. The planet is in orbit around a dim red dwarf called LHS 1140, which is located a mere 40 light-years from Earth in the direction of the constellation Cetus - in astronomical terms, that's pretty close.

The exoplanet, which has been (rather unimaginatively) named LHS 1140b, orbits right in the middle of the red dwarf's habitable zone (HZ) – the region of space around a star in which a planet could potentially sustain liquid water on its surface.

As LHS 1140 is much smaller and cooler than our own star, it doesn't throw out anything close to the levels of radiation that our Sun is capable of emitting. Accordingly, the HZ of the red dwarf occupies a range of space roughly ten times closer to its central ball of fire than the HZ in our own solar system.

The initial discovery was made using the MEarth facility, which detected the tell-tale dip in light from LHS 1140 as LHS 1140b passed between the surface of the star and the observatory.

Follow-up observations carried out by a range of telescopes, including the European Southern Observatory's HARPS instrument then went on to characterize the planet's mass, density, and orbital period.

Scientists believe that one of the major factors that governed the emergence of life on Earth was the presence of liquid water, and so telescopes target distant worlds capable of harboring this precious resource when searching for the hallmarks of life beyond our planet.

LHS 1140b orbits in the HZ of its parent star, which is an important tick in the "can-host-liquid-water" column, but there are a myriad of other factors that could prevent the world from maintaining the vital asset. One of these factors is the red dwarf around which the distant world orbits.

It is estimated that the roughly five-billion-year-old exoplanet orbits its star once every 25 Earth days
It is estimated that the roughly five-billion-year-old exoplanet orbits its star once every 25 Earth days

Red dwarfs have been observed to be extremely volatile soon after their creation. During this period, it is possible that radiation from a red dwarf could strip away significant amounts of the water content of a planet's atmosphere, which could induce the kind of conditions we see on Venus today. Whilst Venus may sometimes be described as Earth's twin, it's pretty far from it, and with a surface temperature exceeding 880 degrees Fahrenheit (470 degrees Celsius), it's probably not the best environment in which to search for life.

However, it is possible that LHS 1140b could have escaped this fate, thanks to its size. The newly discovered exoplanet is believed to have a density of around seven times that of Earth, and a diameter of 18,000 km (11,184 miles), making it 1.4 times the size of our blue marble.

These measurements hint that the planet is most likely comprised of rocky material, and that it harbors a dense iron core. It is possible that the size of the planet allowed a magma ocean to exist on its surface for millions of years. This ocean may have infused the atmosphere with steam for a prolonged period, which would have effectively replenished the planet's water supply.

Furthermore, scientists believe that the red dwarf, as we see it today, is emitting less high-energy radiation and spinning slower than other stars of its type, both of which are factors conducive to life.

It is currently believed that LHS 1140b receives only half as much radiation from its parent star as the Earth does from the Sun. Further observations are set to be carried out by the venerated Hubble Space Telescope, which will study in greater detail just how much radiation is being lavished upon the planet by its star. These observations will in turn inform the likelihood that the planet is capable of sustaining life.

We live in an exciting time of exoplanet discovery and the interconnected search for life. It is possible that LHS 1140b could represent a better prospect for atmospheric analysis than the TRAPPIST-1 worlds and even Proxima-b, which was discovered last year orbiting in the HZ of Proxima Centauri, only four light years from our Sun.

Scroll down to embark on an animated journey to LHS 1140b.

Source: ESO

Artist’s impression of a trip to the super-Earth exoplanet LHS 1140b

4 comments
Bob
I still think radiation that close to a red dwarf would pretty well sterilize any planets regardless of there being water present. I also imagine that many of these so called sightings are the result of sun spots on the stars causing the dips in light intensity as they rotate rather than planets eclipsing the stars. If the red spot on Jupiter has been stable for hundreds of years, I could imagine sun spots on many stars being stable for many years also. Do we actually know ANYTHING about sun spots on other stars or even much about their rate of rotation? I don't think so. People are seeing what they want to see. Most of these assumed planets containing life are wishful thinking. Space is beautiful but incredibly hostile.
Daishi
The results of SETI@home and all of our probes, rovers, and high powered telescopes have mostly all confirmed there is nothing alive that we could ever reach in the foreseeable future. The next closest star is in Alpha Centauri 4.2 light years away. That means even traveling 6.7 million miles per hour (1% of the speed of light) it would still take 420 years just to reach the closest system.
Daishi
So yeah we have essentially ruled out the closest solar systems as having any planets that could sustain life but even if they did and we could reach 6.7 million MPH (or even .67 million) colliding with a particle even the size of a grain of sand at that speed would be catastrophic. That means the technology needed that would get us to even the next closest solar system in under 5,000 or 50,000 years is pretty much science fiction. You would be so far from any solar system in between that you couldn't even really rely on solar power to sustain life over that time. When you realize that solar systems that might actually be suitable to support life might be hundreds of light years away rather than just 4 it starts to look pretty bleak. What that means is that humans have exactly one option to sustain life anywhere that isn't Earth and that's Mars.
Douglas Bennett Rogers
A Dyson style space ship is entirely buildable. It just takes a lot more money than we want to spend on it.