Skip to footer

Did scientists just spot the first 'exomoon'?

Using gravitational microlensing, scientists have discovered a moon circling a giant Jupiter-like alien planet.

|
NASA/JPL-Caltech
Researchers have detected the first potential "exomoon" candidate, a moon orbiting an alien planet beyond our solar system. This artist's illustration shows a possible view of the exomoon (left) and a version of the system if it is actually a star and planet
  • By Mike Wall Space.com

For the first time ever, astronomers may have spotted a moon circling an alien planet — though they'll probably never know for sure exactly what they've found.

A team of scientists detected a pair of faraway objects that could be a giant Jupiter-like alien planet and a rocky exomoon flying freely through space, or a small dim star hosting a planet about 18 times more massive than Earth.

The astronomers used a technique called gravitational microlensing, watching what happens a big foreground object passes in front of a star from our perspective on Earth. The nearby body's gravitational field bends and magnifies the light from the distant star, acting like a lens. [The Strangest Alien Planets Ever (Gallery)]

Analyzing lensing events can reveal a great deal about the foreground object — for example, in the case of a star, whether it hosts a planet and, if so, how massive that world is compared to the star.

In the new study, the team observed one intriguing lensing event using telescopes in New Zealand and the Australian state of Tasmania. They determined that the foreground object has an orbiting companion about 0.05 percent as massive as itself.

"One possibility is for the lensing system to be a planet and its moon, which if true, would be a spectacular discovery of a totally new type of system," Wes Traub, chief scientist for NASA's Exoplanet Exploration Program office at NASA's Jet Propulsion Laboratory in Pasadena, Calif., said in a statement.

"The researchers' models point to the moon solution, but if you simply look at what scenario is more likely in nature, the star solution wins," added Traub, who was not involved in the study.

The team could solve the mystery if they knew how far away from Earth the lensing system, called MOA-2011-BLG-262, lies. If it's relatively nearby, MOA-2011-BLG-262 is probably a starless "rogue planet" and moon; a distant system would have to be as massive as a star to produce the same lensing effects, researchers said.

Unfortunately, the true identity of MOA-2011-BLG-262 will probably remain a mystery forever. Microlensing events are random encounters, so there will be no follow-up observations.

"We won't have a chance to observe the exomoon candidate again," study lead author David Bennett, of the University of Notre Dame, said in a statement. "But we can expect more unexpected finds like this."

And astronomers may be able to measure distances during future microlensing events using the principle of parallax, which describes how the position of an object appears to change when viewed from two different locations.

This strategy could work if observers manage to observe a lensing event with two widely spaced telescopes on Earth, or a ground-based scope and an instrument in orbit, such as NASA's Spitzer or Kepler space telescopes, researchers said.

Astronomers have discovered more than 1,700 alien planets to date, but they're still looking for their first confirmed exomoon.

The new study was led by the joint Japan-New Zealand-American Microlensing Observations in Astrophysics (MOA) and the Probing Lensing Anomalies NETwork (PLANET) programs. It appears in the Astrophysical Journal.

Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @Spacedotcom, Facebook or Google+. Originally published on Space.com.

Copyright 2014 SPACE.com, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

You've read  of  free articles. Subscribe to continue.
Real news can be honest, hopeful, credible, constructive.
What is the Monitor difference? Tackling the tough headlines – with humanity. Listening to sources – with respect. Seeing the story that others are missing by reporting what so often gets overlooked: the values that connect us. That’s Monitor reporting – news that changes how you see the world.
editor@csmonitor.com
Subscribe
Mark Sappenfield
Editor

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.

Subscribe to insightful journalism

QR Code to Did scientists just spot the first 'exomoon'?
Read this article in
https://www.csmonitor.com/Science/2014/0411/Did-scientists-just-spot-the-first-exomoon
QR Code to Subscription page
Start your subscription today
https://www.csmonitor.com/subscribe