For the longest time now, many wonder if there are other planets like Earth that are habitable. What has been described as an "old-age question" started to be asked again as many exoplanets were discovered in recent years.

Now, with a new study, people have an idea of just how many of the planets may support life, and the number, reports say, might be shocking.

Through the use of what today's scientists consider as a "now-retired" Kepler space telescope, a team of researchers has approximated that there are roughly "300 million habitable planets just in the Milky Way."

More so, some of these planets, the researchers said, might even be in the Earth's neighborhood. Many may have wondered what's considered a habitable planet from an astronomer's point of view.

Experts say, first, it has to be rocky and have the ability to support "liquid water on the surface." A habitable planet should have a star nearby, which is the correct temperature, explained experts.

To be exact, scientists continued, the said stars need to be the same temperature as the Sun, "give or take, 1,500 degrees Fahrenheit."

'Exoplanets'

Interestingly, the new study found a few exoplanets fairly close by are meeting the criteria. As indicated in the study, at least four found within 30 light-years of the Sun, "with the closest just 20 light-years away."

Experts also explained, of course, certainly, nothing is for sure, although this study helps those in the field understand what particular exoplanets possess the right ingredients to support life.

Study findings came out after the scientists closely investigated four years of study from the Kepler space telescope.

According to Steve Bryson, the study's lead author and a researcher at NASA's Ames Research Center in California's Silicon Valley, "Kepler already told us there were billions of planets." However, he continued, they know a good chunk of such planets "might be rocky and habitable."

Furthermore, the lead author explained, even though such a result is far from the final value, and water on the surface of a planet is just one of many factors for it to support life, it is extremely exciting that they were able to compute, these worlds are these common with extremely high confidence and accuracy.

Data From ESA's Gaia Mission

The Kepler space telescope had been on a mission to discover how many habitable planets were existing in the galaxy until it ran out of fuel and was retired in 2018.

For this new finding, the information the telescope collected was integrated with data from the Gaia mission of the European Space Agency.

The Gaila mission provided essential information on how much energy is falling on a planet from its host star, revealing a world of possibilities.

In reality, taking into account these planets' atmosphere, scientists found that about 50 percent of Sun-like stars consist of rocky planets that have the ability to host "liquid water on their surfaces."

Experts recommend that before people think they'll be "jetting off to these exoplanets anytime soon," there's more work needed to be done to find out if the study authors' estimates are correct.

Still, Bryson elaborated, it is a big breakthrough for everyone involved in attempting to unlock the universe. And to him, he added, this outcome is an example of how much they have been able to "discover just with that small glimpse beyond our solar system."

Check out more news and information on Space on Science Times.