‘Imagination will often bring us to worlds that never were. But without that we will not go, “said Carl Sagan. So imagine a galaxy filled with tens of millions of black holes and dark, lifeless island worlds – honest, free-floating planets that are unprotected by the gravity and life-giving light of an alien star. It is now becoming increasingly clear that the Milky Way is just such a galaxy. An upcoming NASA mission could find that there are more vicious planets – planets that float in space without orbiting a sun – then there are stars in the Milky Way, a new theorized study.
“This gives us a window into these worlds that we would not otherwise have,” said Samson Johnson, of Ohio State University and lead author of the study. “Imagine our little rocky planet just floating freely in space – that’s what this mission will help us find.”
The Roman Telescope
The study calculated that NASA’s upcoming Nancy Grace Roman Space Telescope could find hundreds of orbiting planets in the Milky Way. Identifying Johnson, Johnson said, will help scientists close the total number of evil planets in our galaxy. Rogue, as free-floating, planets are isolated objects that have masses similar to those of planets. The origin of such objects is unknown, but one possibility is that they were previously associated with a host star.
“The Invisible Galaxy” – 100 million black holes in the Milky Way
“The universe could shake with rough planets and we would not even know it,” said Scott Gaudi, a professor of astronomy and distinguished university scientist at Ohio State and a co-author of the paper. “We would never discover it without doing an in-depth, space-based microlysis study, as Roman will do.”
The Roman telescope, named after NASA’s first chief astronomer, who was also called ‘the mother’ of the Hubble Space Telescope, will try to build the first census of evil planets, which, Johnson said. , scientists could help understand how those planets form. Novel will also have other objectives, including searching for planets orbiting stars in our galaxy.
That process is not well understood, although astronomers know it is messy. Rogue planets could form in the gaseous disks around young stars, similar to those planets still bound to their host stars. After formation, they could later be delayed through interactions with other planets in the system, or even fly through events by other stars. Or they could form as dust and gas swirl together, similar to the way stars form.
The Roman telescope, Johnson said, is designed not only to locate free-floating planets in the Milky Way, but to test theories and models that predict how these planets form.
Search will span 24,000 light-years from the Milky Way
Johnson’s study found that this mission is probably 10 times more sensitive to these objects than existing efforts, which are primarily based on ground-level telescopes. It will concentrate on planets in the Milky Way, between our sun and the center of our galaxy, which are about 24,000 light-years away.
“Several vicious planets have been discovered, but to get a complete picture, our best bet is something like Roman,” he said. “This is a whole new frontier.”
The mission, which is scheduled to launch in the next five years, will search for vicious planets using a technique called gravitational microlensing. That technique requires the gravitational pull of stars and planets to bind the light and magnify stars that pass behind them from the point of view of the telescope.
This illustration shows a rough planet drifting through the galaxy alone. Credit: NASA / JPL-Caltech / R. Hurt (Caltech-IPAC)
Gravitational microlensing – Estein’s general relativity
This microlensing effect is linked to Albert Einstein’s Theory of General Relativity and allows a telescope to find planets thousands of light-years away from Earth – far beyond other planetary detection techniques. Because microlensing only works when the gravitational force of one planet or star bends and the light of another star bends and magnifies, the effect of any given planet as a star is only visible once every few million years for a short time. And because orbiting planets sit in space on their own, without a star nearby, the telescope must be highly sensitive to detect that magnification.
The study estimates that this mission can identify planetary planets that are as large as the masses of Mars. Mars is the second-smallest planet in our solar system and is just slightly larger than half the Earth.
Johnson said these planets are unlikely to support life. “They would probably be extremely cold because they have no star,” he said. (Other research missions in which Ohio State astronomers will search for exoplanets that can host life.) Studying them will help scientists understand more about how all planets form, he said.
“If we find a lot of low-mass planets, we will know that if stars form planets, they are likely to emit a lot of other things in the galaxy,” he said. “This helps us to tackle the path of planet formation in general. As many as six billion terrestrial planets in our galaxy, according to new estimates
Source: Samson A. Johnson et al. Predictions from the Nancy Grace Roman Space Telescope’s Galactic Exoplanet Survey. II. Free floating rates for planetary detection, The Astronomical Journal (2020). DOI: 10.3847 / 1538-3881 / aba75b, iopscience.iop.org/article/10. … 847 / 1538-3881 / aba75b
The Daily Galaxy, Sam Cabot, via The Ohio State University
Image Credits: NASA
