The Kepler mission has detected thousands of exoplanets since 2014, with 30 planets less than twice the size of Earth that are now known to orbit within the habitable zones of their stars.
Launched from Cape Canaveral on March 7, 2009, the Kepler The telescope has aided in the search for planets outside the solar system.
When launched, it weighed 2,320 pounds (1,052 kg) and is 15.4 feet long by 8.9 feet wide (4.7 m × 2.7 m).
the satellite normally searches for "Earth-like" planets, which means they are rocky and orbit within that orbit within the habitable zone or "Goldilocks" of a star.
In total, Kepler has found around 5,000 unconfirmed "candidate" exoplanets. with another 2,500 "confirmed" exoplanets that scientists have shown to be real.
Kepler is currently in the mission & # 39; K2 & # 39; to discover more exoplanets.
K2 is the second mission of the spacecraft and was implemented by necessity on desire since two reaction wheels failed in the spacecraft.
These wheels control the direction and altitude of the spacecraft and help point it in the right direction.
The modified mission observes exoplanets around faint red dwarf stars.
While the planet has encountered thousands of exoplanets during its eight-year mission, five in particular have excelled.
Kepler-452b, nicknamed "Earth 2.0", shares many features with our planet despite being 1,400 light-years away. It was found by NASA's Kepler telescope in 2014
1) & # 39; Earth 2.0 & # 39;
In 2014, the telescope made one of its greatest discoveries when it saw the exoplanet Kepler-452b, dubbed & # 39; Earth 2.0 & # 39 ;.  The object shares many characteristics with our planet despite being 1,400 light-years away.
It has an orbit of similar size to Earth, receives approximately the same amount of sunlight and has the same duration of the year.
Experts still do not make sure if the planet hosts life, but if the plants were transferred there, they are likely to survive.
2) The first planet to orbit two stars
Kepler found a planet that orbits two stars, known as a binary star system, in 2011.
The system, known as Kepler -16b, is about 200 light years from Earth.
Experts compared the system with the famous & # 39; double sunset & # 39; represented on the home planet of Luke Skywalker Tatooine in & # 39; Star Wars: A New Hope & # 39 ;.
3) Find the first habitable planet outside the solar system
Scientists found Kepler-22b in 2011, the first habitable planet found by astronomers outside the solar system.
The habitable super-Earth appears to be a large rocky planet with a surface temperature of approximately 72 ° F (22 ° C), similar to a spring day on Earth.
4) Discovering a & # 39; super-Earth & # 39;
The telescope found its first & # 39; super-Earth & # 39; in April of 2017, a huge planet called LHS 1140b.
Orbit a red dwarf star about 40 million light-years away, and scientists believe it contains giant oceans of magma.
5) Find the star & # 39; Trappist-1 & # 39; system
The Trappist-1 star system, which houses a record of seven planets similar to Earth, was one of the greatest discoveries of 20 17.
Each of the planets, orbiting around a dwarf star only 39 million light years, probably contains water on its surface.
Three of the planets have such good conditions that scientists say that life may have already evolved in them.
Kepler detected the system in 2016, but the scientists revealed the discovery in a series of documents published in February this year.
Kepler is a telescope that has an incredibly sensitive instrument known as a photometer that detects the smallest changes in the light emitted by stars
How does Kepler discover planets?
The telescope has an incredibly sensitive instrument known as a photometer that detects the slightest changes in light emitted by stars.
tracks 100,000 stars simultaneously, looking for telltale drops in the intensity of light that indicate a planet in orbit that pbades between the satellite and its distant target.
the planet pbades in front of a star seen from Earth, the event is called & # 39; transit & # 39 ;.
Small drops in the brightness of a star during a transit can help scientists determine the orbit and size of the planet, as well as the size of the star.
According to these calculations, scientists can determine if the planet is in the "habitable zone" of the star and, therefore, if it could accommodate the conditions for extraterrestrial life to grow.