Scientists uncovered observations of an exoplanet 17,000 light-years away made by the now-retired Kepler Space Telescope, a report in ScienceAlert reveals.
The exoplanet, dubbed K2-2016-BLG-0005Lb, was observed using a method called gravitational microlensing in 2016.
The discovery could have implications in our search for extraterrestrial life as it shows a celestial object strikingly similar to our neighbor Jupiter in the distant reaches of space. Could another Earth-like planet exist in its vicinity?
A strikingly familiar alien world
K2-2016-BLG-0005Lb is located more than twice the distance away compared to Kepler's previous record-holder for the most distant alien world. The distant exoplanet is almost an exact twin of Jupiter, as it has a similar mass and is orbiting its star at a similar distance to Jupiter in our solar system. The researchers behind the observation published a paper detailing their findings in the Monthly Notices of the Royal Astronomical Society.
"Kepler was never designed to find planets using microlensing so, in many ways, it's amazing that it has done so," explained University of Manchester astronomer Eamonn Kerins.
After launching in 2009, the Kepler observatory revealed more than 3,000 exoplanets over a period of 10 years. The observatory predominantly used the transit method, which observes dips in starlight to pinpoint exoplanets orbiting and momentarily blocking a portion of light from their stars.
Microlensing relies on the gravitational curvature of space-time around large objects, such as planets. That curvature of space-time can be used as a magnifying glass to very briefly peer even further into specific locations in space.
This method was used to observe the farthest exoplanet from Earth to date, at a distance of 25,000 light-years. Though Kepler wasn't specifically designed for microlensing, a group of researchers led by the University of Manchester recently thought to look through old data from the space observatory to see what they could find. They identified 27 events of microlensing, five of which had never been identified before.
"To see the effect at all requires almost perfect alignment between the foreground planetary system and a background star," Kerins said.
"The chance that a background star is affected this way by a planet is tens to hundreds of millions to one against. But there are hundreds of millions of stars towards the center of our galaxy. So Kepler just sat and watched them for three months."
"Jupiter's identical twin"
One of the events observed was the data for K2-2016-BLG-0005Lb, which was later corroborated to be an exoplanet using data from other ground-based observatories. The researchers found that the exoplanet is approximately 1.1 times the mass of Jupiter, and it orbits its star at a circular distance of 4.4 astronomical units, which is just a little more than Jupiter's average distance from the Sun of 5.2 astronomical units. "It is basically Jupiter's identical twin in terms of its mass and its position from its Sun, which is about 60 percent of the mass of our own Sun," Kerins said.
Though we don't know a lot about the Jupiter twin, the fact that such a familiar-looking planet could exist at such a distance from Earth has implications when it comes to our search for extraterrestrial life.
Jupiter has played a large role in allowing life to evolve on Earth, namely due to the fact that its large mass made it act as an asteroid shield of sorts, steering dangerous space rocks away from Earth.
The new discovery hints that a very similar solar system to ours could be out there with the capacity for allowing life to flourish. Soon NASA's Nancy Grace Roman Space Telescope, designed specifically for gravitational microlensing, will provide the global astronomical community with even more data, possibly leading to the discovery of even more surprisingly similar planets to the ones that surround Earth.