Spotting new planets is not very common in our solar system. The last time we spotted a new world orbiting our sun was in 1930, when astronomer Clyde Tombaugh discovered Pluto. Pluto was labeled a planet until 2006, when it was downgraded to a dwarf planet. Last January, astronomers from Caltech announced they had evidence of a new Planet Nine, but no one’s seen it yet.
Planets in our solar system are rare but there are many others out there across the rest of the galaxy. NASA announced yesterday that astronomers working with its Kepler space telescope have identified 1,284 new exoplanets. Exoplanets are planets that orbit stars other than our sun.
“This announcement more than doubles the number of confirmed planets from Kepler,” Ellen Stofan, chief scientist at NASA Headquarters in Washington, said in a statement. “This gives us hope that somewhere out there, around a star much like ours, we can eventually discover another Earth.”
Of the newly confirmed planets, nine qualify as the most sought-after type of all: ones that could possibly support life. These planets are less than twice the size of Earth, which means they likely have solid surfaces. These planets orbit their stars in the so-called Goldilocks zone, where the temperature stays within the not-too-hot, not-cold-cold range. This is an ideal environment for liquid water to exist. If life as we know it is going to emerge anywhere in space, planets like these are the first place to look.
Looking for Data
The newly announced planets were discovered by NASA’s Kepler telescope. The Kepler Mission was launched in 2009, and is the first NASA mission to find potentially habitable Earth-size planets, NASA said.
Kepler has searched for planets by looking closely at 150,000 stars, which is just a tiny amount, compared to the 300 billion or so in the Milky Way. The telescope finds planets by looking for the slight dimming of light that occurs when an orbiting planet crosses its face.
NASA
The Kepler telescope, pictured here, is on a mission to detect planets outside of our solar system.
This method can produce false data in a number of ways. Eliminating the false planets has usually involved follow-up sightings by other telescopes, which can be a slow process. Timothy Morton, an astronomer and Kepler telescope researcher, has made this usually long process much simpler with a new computer program. This program takes into account a number of different factors including the size and color of the star, the overall stellar population of the galaxy and more. Together, all this data can determine if a possible planet is actually a real planet with a 99% certainty. Only the ones that meet or exceed this percentage are confirmed as planets—and the 1,284 announced by NASA did just that.
“Kepler is interested in statistics,” said Natalie Batalha, Kepler mission scientist at NASA’s Ames Research Center in Moffett Field, California. “We are searching the galaxy to see how far we have to look to find potentially habitable planets.”
Signs of Life?
Of 1,284 planets confirmed, only nine are Earth-like planets. Habitable planets, like Earth, can be missed entirely because of their small size and because they may orbit at an angle similar to the Kepler telescope. This can make them appear to pass above or below their parent star and they don’t cause the dimming light the telescope seeks.
Future telescope missions including the Transiting Exoplanet Survey Satellite (TESS) and the James Webb Space Telescope (JWST) will follow up on these findings. These two telescopes will closely look for signs of life such as water, methane and carbon dioxide.
One of humanity’s great mysteries—whether we’re alone in the universe—is still unresolved. But what these 1,284 new planets do make clear is that plenty of worlds out there could make comfortable homes for other life forms.
Why do you think the recent discovery of so many new planets is so important to scientists?
