The Milky Way is so big, are there any other potentially habitable planets?

Based on humanity’s technological level and aerospace capabilities, the Milky Way is an unreachable goal for humanity. However, according to scientists' speculations and probability calculations, there must be other planets suitable for human habitation in the vast galaxy.

New research results indicate that there may be at least 300 million potentially habitable planets in the Milky Way. Scientists have found that about half of the Sun-like stars in the Milky Way may be home to Earth-like planets. Finding planets with environments similar to those on Earth is also what scientists believe is the best way to find aliens.

Scientists believe that in order to search for habitable planets, they need to search for similar star systems in the Milky Way according to the parameters of the Earth and the Sun, and find those "habitable planets" located in the habitable zone. These potentially habitable planets must meet at least two conditions: first, the star they orbit has a similar temperature and age to the sun; second, the distance of the planet from the star is equivalent to the distance from the earth to the sun, that is, it is in the habitable zone.

The biggest contributor behind such research results is the exoplanet data collected by the Kepler space telescope between 2009 and 2018. The Kepler space telescope was launched by NASA in March 2009. Its mission is to search for planets orbiting other stars that are similar to the size of the Earth. Using photometers, the brightness of 150,000 stars is continuously monitored within a fixed field of view, and the data is subsequently transmitted back to Earth for analysis. The program's lifespan was originally set at 3.5 years, but due to continued failures of the telescope, the entire program was repeatedly extended until 2018, when Kepler officially announced its retirement.

During its lifetime, Kepler observed more than 530,000 stars and discovered 2,800 exoplanets. In 2015, NASA released data on four planets discovered by Kepler that are in the habitable zone. Among them, Kepler 438b, Kepler 442b, and Kepler 452b are nearly Earth-sized and may be rocky. The fourth is Kepler 440b, a super-Earth.

So, it is very possible that there are planets suitable for human habitation in the Milky Way, but with the current level of science and technology and capabilities of mankind, we are still unable to go and find out. In the future, with the development of human science and technology, we may be able to conduct field investigations on these planets.