Suspected Exomoon Spotted 8,000 Light-Years Away

Suspected Exomoon Spotted 8,000 Light-Years Away

Suspected Exomoon Spotted 8,000 Light-Years Away

Astronomers may have detected the first moon outside the solar system, around 8,000 light years from Earth, Reuters reported on Thursday. Kepler-1625b Exomoon vs Solar System MoonsThe exomoon is much larger than the biggest moon of the solar system, Jupiter's Ganymede.

The "exomoon" was found orbiting exoplanet Kepler-1625b - around 4,000 light years away from earth - by two Columbia University astronomers.

Our hunt for exoplanets (planets further into the cosmos) has thrown up some truly unusual and fascinating examples in recent years, with confirmed discoveries now numbering in the thousands. While our own Moon is mostly thought to have formed when a collision shot off some material that has become the rock we see today, that would not be possible with this exomoon because both the moon and the planet it orbits are made up of gas. Moons in the solar system are either rocky or icy.

Astronomers David Kipping and Alex Teachey published their results in Science Advances journal.

The team behind this intriguing discovery, researched more than 250 planets outside our solar system using the space telescope NASA Kepler. They say the first exomoon is rather odd because of its larger size, which is comparable to the diameter of our solar system's Neptune.

Kepler, now virtually out of gas after an extraordinary mission, detected more than 2,600 exoplanets by looking for the tell-tale dip in brightness that occurs when a planet transits, or moves in front of its parent star as seen from Earth, blocking some of the star's light.

Teachey and Kipping relied on the "transit" method, which is already used by researchers to discover almost 4,000 planets outside our solar system, called exoplanets. "When we look for an Earth twin, I think one of the most obvious things you might ask is, 'Does it have a moon twin, ' because that seems to have a large influence", he notes.

Unfortunately, the scientists' time on Hubble ended before they could completely observe the second transit. It clearly indicated a moon that was trailing behind the planet. "But we knew our job was to keep a level head testing every conceivable way in which the data could be tricking us until we were left with no other explanation". This is interpreted as a so-called transit timing variation, caused by an unaccounted for gravitational tug on the planet by an unseen body. "Both bodies, however, are considered to be gaseous and therefore unsuitable for life as we know it", Kipping added.

In this search, the Neptune-sized moon would have been among the easiest to first detect because of its large size. These observations have to be done from space; the rotation of Earth means that ground-based telescopes spin away from their targets before they can capture a whole event. That behavior is common with a planet and moon orbiting a common center of gravity, which causes the planet to wobble from its previously-expected location.

Scientists from Columbia University have discovered the first accespoint exoplanets beyond our Solar system.

"Furthermore, the size we've calculated for this moon, about the size of Neptune, has hardly been anticipated, and so that, too, is reason to be careful here", Teachey said. Using the Hubble Space Telescope, Kipping and Teachey observed how the light of the star dimmed as the planet crossed in front of its star.

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