There are about 160 billion planets in our galaxy.
According to experts, exoplanets can be surprisingly common in our Milky Way galaxy, and their number is likely to exceed the number of stars.
According to the calculations of astronomers, on average, each star has 1.6 planets around it, given that according to modern estimates, there are about 100 billion stars in the Milky Way, we can say that there are 160 billion planets in our galaxy.
A significant number of these planets are small solid cosmic bodies, similar in size and physical properties to the Earth. The exact number of minor planets is not yet possible to determine, but it is obvious that their number exceeds the number of so-called gas giants.
“This study is more statistical in nature, but based on all the astronomical studies conducted over the past few years, we can say that the planets around the stars for the Milky Way are more the norm, and not the exception to the rule,” says study author Arnaud Cassan from the Paris Institute of Astrophysics. “More recently, we have to realize our galaxy is not only a place with billions of stars, but also a place with a huge number of planets, many of which are still hidden from us,” he says.
To date, the number of confirmed exoplanets includes about 700 objects located outside the Solar System. Another approximately 2,300 are so-called “planet candidates”. Most of the exoplanets currently detected are detected using one of two methods: transit photometry or radial velocity.
For example, the modern Kepler orbiting telescope uses the first method and it allows you to find large exoplanets located in the immediate vicinity of their stars. The second method is more complex, since it is based on the gravitational deviations of stars and large planets, but it allows you to find much smaller planets that are further removed from the stars. Scientists say that both of these methods are productive.
Cassan says that now another technique is being worked out for exoplanets – gravitational microlensing, which was previously developed for the study of distant galaxies. Summing up the three methods of detecting exoplanets, tens of thousands of exoplanets may be discovered in the next 10-15 years, scientists predict.
Extrapolating already available data to the entire Milky Way galaxy, French scientists say that about a sixth of the stars in our galaxy have so – called hot Jupiters near them, about half are planets similar to Neptune, and about 75% are planets conventionally called “super – Earths”. At the same time, experts say that their study takes into account only the range of 0.5-10 astronomical units from the star as a “habitable territory”.
“We can say that low-mass planets like’ super-Earths ‘ and Neptune – like planets are significantly more common than giant planets like Saturn or Jupiter,” Cassan says.
Based on current data, astronomers say on average in the range of 0.5 to 10 AU. a star in the Milky Way has 1.6 planets, that is, in total in our galaxy, according to the most conservative estimates, there are about 160 billion planets. “The actual number of planets is likely slightly higher, as some stars have planets closer than 0.5 au, while others are farther than 10 au,” says Cassan.