Our Earth in context with other worlds
Earth is special, even in the context of the thousands of planets outside of our solar system so far found by astronomers.
Why it matters: The holy grail for researchers remains finding an Earth-sized planet in a similar orbit to our Earth around a Sun-like star.
What's happening: While astronomers haven't yet found proof-positive of an Earth twin, they continue to use high-powered tools on the planet and above it to find more and more planets out there in the universe.
- Scientists have found more than 4,000 alien planets, but none of them appear to be exactly like our own.
- "So far, our home is unique in the universe," NASA said in an FAQ. "We have found many Earth-sized rocky exoplanets, some of which are in the habitable zones of their stars."
What's next: Scientists hope to perform follow-up observations on some of the most promising worlds found so far in order to see if any of them may truly be habitable.
- At the moment, even the most powerful telescopes are unable to gather enough detailed data to be able to say that any planet so far is habitable, but future telescopes should aid in the hunt in the coming years.
- Astronomers are in the process of setting their priorities for the community for the next 10 years, a process known as the "decadal survey" that will help NASA decide what missions to fund.
- Major missions now up for consideration could help researchers characterize far-off planets, peering into their atmosphere and helping scientists learn more about what may be lurking below.