Astronomers detect up to 170 giant planets floating in space.
About 200 giant planets have been seen drifting aimlessly through space, according to a remarkable discovery by astronomers. Researchers from the European Southern Observatory say that these “rogue planets” float in space and do not orbit a star, as Earth and the rest of the planets in our solar system do.
The planets are in a star-forming region relatively close to our Sun in the southern constellations of Upper Scorpius and Ophiuchus. Although there may be billions of these rogues in the Milky Way, the 170 scientists found in this section of the galaxy represent the largest group of rogue planets discovered to date.
“We didn’t know how many to expect and we are excited to have found so many,” says the study’s first author, Dr. Nuria Miret-Roig of the University of Bordeaux in a Press release.
The rogue planets are a bit of mystery to astronomers. For comparison, our Sun has at least eight planets orbiting it (nine if you count Pluto). From what scientists can tell, most other stars also have planets surrounding them.
Planets ‘glowing’ in the dark
An international team combined observations from space and ground telescopes to spot the rogues. Since these mysterious worlds float away from any stars that might illuminate them, it would normally be impossible to imagine them. However, even in the few million years after their formation, they are still hot enough to glow.
The sensitive cameras of the VLT (Very Large Telescope) and VISTA (Visible and Infrared Survey Telescope for Astronomy) identified them directly. About 70 of these masses are similar to Jupiter and it would be too cold to Life support based on what we know.
To detect so many at once, the researchers also used data spanning about 20 years from various different telescopes, including the Gaia satellite of the European Space Agency. It is a great step in the exploration and understanding of our universe.
“We measure the small movements, colors and luminosity of tens of millions of sources in a large area of the sky,” explains Miret-Roig. “These measures allowed us identify the dimmest objects in this region, the rogue planets. ”
“The vast majority of our data comes from ESO’s observatories, which were absolutely critical to this study. His wide field of vision and unique sensitivity were key to our success, ”adds project leader Dr. Herve Bouy. “We used tens of thousands of wide-field images from ESO’s facilities, corresponding to hundreds of hours of observations and literally tens of terabytes of data.”
Are there rogue planets all over the galaxy?
The study, published in the journal Nature astronomy, suggests that there could be many more of these elusive starless planets out there. In fact, they can even outnumber the stars themselves.
“There could be several billion of these free-floating giant planets freely roaming the Milky Way without a host star,” says Dr. Bouy.
Analysis of the newly found rogues could reveal clues to how these planets form. One theory is that they are collapsed gas clouds that are too small to become full-blown stars. Another theory is that they were previously orbiting a host star. before letting go of its gravitational pull.
The team hopes to continue studying these objects using ESO’s Extremely Large Telescope (ELT), currently under construction in the Chilean Atacama Desert.
“These objects are extremely faint and little can be done to study them with current facilities,” continues Bouy. “The ELT will be absolutely crucial in gathering more information on most of the rogue planets that we have encountered.”
The older they are, the colder they are
The exact number of rogue planets The team found that it is difficult to pin down because scientists cannot obtain precise measurements of the mass of each planet. Those that are about 13 times larger than Jupiter are probably not planets and the team does not include them in their findings.
So the study authors analyzed the brightness of each rogue to provide an upper limit to the number that scientists think are floating in space. Brightness is related to the age of the object, and older planets are dimmer and cooler.
An earlier study by American scientists suggests that the Milky Way could be home to more than 100 billion rogue planets.