Skip to main content

Wandering planets could outnumber the stars in our galaxy

Rogue Planet (Animation)

In the depths of space, in the vast expanses between stellar systems, there float lonely planets which have no star to orbit around. These isolated travelers are called rogue planets, but we really don’t know how many of them are out there. Now, a new study suggests that NASA’s upcoming Nancy Grace Roman Space Telescope could be able to identify hundreds of these rogue planets, which could even outnumber the stars in our galaxy.

“The universe could be teeming with rogue planets and we wouldn’t even know it,” co-author of the study Scott Gaudi, professor of astronomy at Ohio State University, said in a statement. “We would never find out without undertaking a thorough, space-based microlensing survey like Roman is going to do.” Roman will search for rogue planets in particular regions of space and, from this data, scientists can ascertain how many rogue planets might exist.

High-resolution illustration of the Roman spacecraft against a starry background.
High-resolution illustration of the Roman spacecraft against a starry background. NASA's Goddard Space Flight Center

Microlensing is a technique in which astronomers use telescopes like Roman to see distant objects, by looking at the way light is bent when another object passes between us and the target. This allows them to see far-off stars by using these intermediate objects like a magnifying glass.

Rogue planets are typically hard to spot because they are not near to a source of light like a star. But Roman will be able to detect them using microlensing. “This gives us a window into these worlds that we would otherwise not have,” lead author Samson Johnson, a graduate student at Ohio State University said in another statement. “Imagine our little rocky planet just floating freely in space — that’s what this mission will help us find.”

One debate around rogue planets is how they came to be alone — and whether they once did orbit a star. So studying them can help researchers to learn about how planets and stellar systems form.

“As our view of the universe has expanded, we’ve realized that our solar system may be unusual,” Johnson said in the statement. “Roman will help us learn more about how we fit in the cosmic scheme of things by studying rogue planets.”

The findings are published in The Astronomical Journal.

Editors' Recommendations

Georgina Torbet
Georgina is the Digital Trends space writer, covering human space exploration, planetary science, and cosmology. She…
James Webb captures a stunning colliding pair of galaxies
This image from the NASA/ESA/CSA James Webb Space Telescope depicts IC 1623, an entwined pair of interacting galaxies which lies around 270 million light-years from Earth in the constellation Cetus. The two galaxies in IC 1623 are plunging headlong into one another in a process known as a galaxy merger. Their collision has ignited a frenzied spate of star formation known as a starburst, creating new stars at a rate more than twenty times that of the Milky Way galaxy.

A recently released image from the James Webb Space Telescope shows the stunning galaxies IC 1623 A and B, located 270 million light-years away, which are in the process of merging. As the two galaxies crash together, they are intersecting and feeding high levels of star formation, creating an area known as a starburst region.

James Webb captured the image using three of its instruments: MIRI, NIRSpec, and NIRCam. Each instrument looked in a different portion of the infrared to see the different features of the merging galaxy. "This interacting galaxy system is particularly bright at infrared wavelengths, making it a perfect proving ground for Webb’s ability to study luminous galaxies," Webb scientists write.

Read more
The ‘Phantom Galaxy’ looks stunning in this Webb telescope image
The Phantom Galaxy captured by the James Webb Space Telescope.

The James Webb Space Telescope is continuing to deliver astonishing images of deep space, with this latest one revealing the incredible beauty of M74, otherwise known as the Phantom Galaxy.

The Phantom Galaxy has been captured before by the Hubble Space Telescope, but Webb’s more powerful infrared technology reveals for the first time its “delicate filaments of gas and dust in the grandiose spiral arms which wind outwards,” as per the European Space Agency (ESA), which is overseeing the Webb mission with NASA and the Canadian Space Agency (CSA).

Read more
See elements as colors in this galaxy where stars are being born
This week, we feature an image of the spiral galaxy NGC 4303, also known as Messier 61, which is one of the largest galactic members of the Virgo Cluster. Being a so-called starburst galaxy, it has an unusually high amount of stars being born, and has been used by astronomers as a laboratory to better understand the fascinating phenomena of star formation.

From Hubble to the James Webb Space Telescope, when you think of the tools that capture images of space some of the first examples that come to mind are likely to be space-based telescopes. These telescopes have the advantage of being above the water vapor in Earth's atmosphere which can distort readings, and allows them to look out at the universe in great detail. But there are advantages of ground-based telescopes as well, such as being able to build much larger structures and to more easily upgrade these telescopes with new instruments.

One such ground-based telescope is the European Southern Observatory (ESO)'s Very Large Telescope. As the name suggests it is indeed very large, being made up of four separate telescopes each of which has an 8.2-meter (27 feet) primary mirror and which work together to look out at space in the visible light and infrared wavelengths. On the telescope named Yepun sits an instrument called MUSE, or the Multi-Unit Spectroscopic Explorer (MUSE), which uses a technology called adaptive optics to collect high-resolution data about areas of space.

Read more