Our Milky Way is home to at least 17 billion planets that are similar in size to Earth, a new estimate suggests. That is more than two Earth-size planets for every person on the globe.
Just how many are located in the sweet spot where water could exist is “simply too early to call,” said Francois Fressin of the Harvard-Smithsonian Center for Astrophysics, who presented his work at an astronomy meeting on Monday.
It is the first reliable tally of the number of worlds outside the solar system that are the size of Earth, but the hunt for our twin is far from over.
Despite the explosion of exoplanet discoveries in recent years, one find remains elusive: A planet that is not only the right size, but also in the so-called Goldilocks zone, where it is not too hot or too cold for water to be in liquid form on the surface.
The sheer number of Earth-size planets gives astronomers a starting point to narrow down which ones are in the habitable zone.
Fressin and his team came up with their figure by conducting a fresh analysis of data collected by NASA’s Kepler spacecraft, which was launched in 2009 to track down other “earths.” They estimated that at least one in six stars in the galaxy hosts a planet the size of ours, translating to at least 17 billion Earth-size worlds.
Using a different method, a team from the University of California, Berkeley and the University of Hawaii separately came up with a similar estimate. They calculated that 17 percent of distant stars have planets that are the same size as Earth or slightly larger.
The findings were presented at the American Astronomical Society in Long Beach, California.
Meanwhile, the Kepler spacecraft continues to spot planets as they pass between Earth and the star they orbit. It found 461 new candidate planets, bringing the total to 2,740 potential planets, mission scientist Christopher Burke said at the SETI Institute.
Most of the new Kepler finds were driven by discoveries of Earth-size planets and super-Earths. Four of those are thought to reside in the Goldilocks zone, but more observations are needed.
Nearly half of China’s major cities are suffering “moderate to severe” levels of subsidence, putting millions of people at risk of flooding, especially as sea levels rise, according to a study of nationwide satellite data released yesterday. The authors of the paper, published by the journal Science, found that 45 percent of China’s urban land was sinking faster than 3mm per year, with 16 percent at more than 10mm per year, driven not only by declining water tables, but also the sheer weight of the built environment. With China’s urban population already in excess of 900 million people, “even a small portion
UNSETTLING IMAGES: The scene took place in front of TV crews covering the Trump trial, with a CNN anchor calling it an ‘emotional and unbelievably disturbing moment’ A man who doused himself in an accelerant and set himself on fire outside the courthouse where former US president Donald Trump is on trial has died, police said yesterday. The New York City Police Department (NYPD) said the man was declared dead by staff at an area hospital. The man was in Collect Pond Park at about 1:30pm on Friday when he took out pamphlets espousing conspiracy theories, tossed them around, then doused himself in an accelerant and set himself on fire, officials and witnesses said. A large number of police officers were nearby when it happened. Some officers and bystanders rushed
Beijing is continuing to commit genocide and crimes against humanity against Uyghurs and other Muslim minorities in its western Xinjiang province, U.S. Secretary of State Antony Blinken said in a report published on Monday, ahead of his planned visit to China this week. The State Department’s annual human rights report, which documents abuses recorded all over the world during the previous calendar year, repeated language from previous years on the treatment of Muslims in Xinjiang, but the publication raises the issue ahead of delicate talks, including on the war in Ukraine and global trade, between the top U.S. diplomat and Chinese
HYPOCRISY? The Chinese Ministry of Foreign Affairs yesterday asked whether Biden was talking about China or the US when he used the word ‘xenophobic’ US President Joe Biden on Wednesday called for a hike in steel tariffs on China, accusing Beijing of cheating as he spoke at a campaign event in Pennsylvania. Biden accused China of xenophobia, too, in a speech to union members in Pittsburgh. “They’re not competing, they’re cheating. They’re cheating and we’ve seen the damage here in America,” Biden said. Chinese steel companies “don’t need to worry about making a profit because the Chinese government is subsidizing them so heavily,” he said. Biden said he had called for the US Trade Representative to triple the tariff rates for Chinese steel and aluminum if Beijing was