New Estimates Suggest There Are Around 300 Million Habitable Planets in Our Galaxy

In the Milky Way galaxy alone, there are over 300 million potentially habitable exoplanets. This indicates that 300 million planets are likely to have the necessary conditions for life—and sophisticated life—to evolve on their surfaces. Are we the only ones in the universe?

How vast is the universe in which we live? Given our existing technology and measurement of the universe, we are unable to acquire this answer. We can make educated guesses, but we are still a long way from investigating the universe.

We can get a better idea of the size of our galaxy. Overall, it's a vast location packed with planets. But how many of these worlds are like Earth, and how many of them are habitable? This is another difficult solution to obtain, but we can do the math based on observations over the years.

According to new research based on data from the Kepler space observatory, there could be up to 300 million potentially habitable planets in our galaxy. The nice news about the new estimations is that they could be very close to Earth; none of these possibly habitable exoplanets are more than 30 light-years away.

Researchers from NASA, the SETI Institute, and other institutions from around the world collaborated in one large project to help us better comprehend the galaxy we live in.

While 300 million planets may appear to be a large number, it is far from the total number of planets thought to exist in our galaxy. According to our best calculations, the Milky Way has at least one planet for every star, implying that the galaxy we dwell in could have anywhere from 100 billion to 400 billion planets.

The visible universe

The observable universe, on the other hand, has at least 125 billion galaxies.

According to co-author Jeff Coughlin, a SETI Institute scientist who studies exoplanets, "this is the first time that all of the components have been put together to produce a solid count of the number of potentially habitable planets in the galaxy."

The best aspect is that once we know how many habitable exoplanets there are in the galaxy, we can reconsider the Drake Equation.

“This is a key term of the Drake Equation, used to estimate the number of communicable civilizations — we’re one step closer on the long road to finding out if we’re alone in the cosmos,” the researcher revealed.

The Drake Equation assesses the likelihood of how many possibly advanced alien civilizations exist in our galaxy and how many of them we can contact from Earth.

Estimate Revised

Researchers looked for worlds similar to Earth in their revised estimate of possible habitable planets in our galaxy. They also took into account planets that are most likely stony in nature.

Scientists then looked for Sun-like stars in the universe, seeking for stars that are around the same age and temperature as our sun.

Another crucial element to evaluate is whether exoplanets match the conditions for liquid water to exist on their surfaces, as this has a significant impact on the habitability of faraway worlds. All of this was taken into account in the latest study, which varies from prior studies that merely looked for potentially habitable planets in the galaxy, relying mainly on the planet's distance from the star to make their estimates.

The new study takes into account a few extra factors, such as how much light from the star strikes the planet; this is an essential component in evaluating the likelihood of liquid water on the planet's surface.

Researchers examined data obtained by the Kepler Space Telescope as well as data collected by the European Space Agency's Gaia Mission.

The Kepler space telescope, which stopped searching for exoplanets in 2018, discovered over 2,800 exoplanets throughout the cosmos. Many of these worlds are still awaiting confirmation, which might increase the number of planets identified in the cosmos to date.

There are 4,935 confirmed exoplanets, 8709 NASA exoplanet candidates, and 3,706 solar systems as of March 3, 2022. More information is available here.

SETI's news release can be found here.

Reference(s): The Astronomical Journal