🕷️ Crawler Inspector

 [Skip to main content](https://www.livescience.com/4597-greatest-mysteries-alien-life-exist.html#main) Live Science Plus \- Join our community JOIN NOW 10 Member Features 24/7 Access Available 25K+ Active Members  Exclusive Newsletters Science news direct to your inbox  Member Competitions Win exclusive prizes  Exclusive Content Premium articles & videos  Early Access First to see new features  Private Forums Connect with members  Monthly Rewards Surprise gifts & perks GET LIVE SCIENCE PLUS It's quick and easy to access Live Science Plus, simply enter your email below. We'll send you a confirmation and sign you up for our daily newsletter, keeping you up to date with the latest science news. By submitting your information you agree to the [Terms & Conditions](https://futureplc.com/future-member-terms-and-conditions/) and [Privacy Policy](https://futureplc.com/privacy-policy/) and are aged 16 or over. FIND OUT ABOUT OUR MAGAZINE Want to subscribe to the magazine? Click the button below to find out more information. [Find out more](https://www.livescience.com/4597-greatest-mysteries-alien-life-exist.html)  Welcome to Live Science Plus \! Hi , Your membership journey starts here. Keep exploring and earning more as a member. [MY ACCOUNT](https://www.livescience.com/my-account) ***  Earn your first badge Complete 1 quiz to unlock your first badge. Keep earning badges Explore ways to get more involved as a member.  Live Science Quizzes Quick, fun science challenges. [Play Now](https://www.livescience.com/quizzes)  Science Crosswords Short, brain-teasing puzzles. [Play Now](https://www.livescience.com/tag/science-crossword) *** See what you’ve unlocked. Explore your membership benefits. [Explore](https://www.livescience.com/membership) Member Exclusives Science Newsletters Select the newsletters you'd like to receive and enter your email below. [View all](https://www.livescience.com/newsletter) *** [Sign Out]() Open menu Close main menu [ Live Science](https://www.livescience.com/) [Sign up to our newsletter Newsletter](https://www.livescience.com/newsletter) [RSS](https://www.livescience.com/feeds.xml) Sign in - View Profile - Sign out Search - [Space](https://www.livescience.com/space) - [Health](https://www.livescience.com/health) - [Planet Earth](https://www.livescience.com/planet-earth) - [Animals](https://www.livescience.com/animals) - [Archaeology](https://www.livescience.com/archaeology) - [Physics & Math](https://www.livescience.com/physics-mathematics) - [Technology](https://www.livescience.com/technology) - More - [Human Behavior](https://www.livescience.com/human-behavior) - [Chemistry](https://www.livescience.com/chemistry) - [Science news](https://www.livescience.com/news) - [Opinion](https://www.livescience.com/opinion) - [Life's Little Mysteries](https://www.livescience.com/tag/lifes-little-mysteries) - [Science quizzes](https://www.livescience.com/quizzes) - [Crossword](https://www.livescience.com/human-behavior/arts-entertainment/live-science-crossword-puzzle) - [About us](https://www.livescience.com/about-live-science) - [Newsletters](https://www.livescience.com/newsletter) - [Follow us](https://www.livescience.com/technology/internet/follow-live-science-on-social-media) - [Story archive](https://www.livescience.com/archive) Trending - [Artemis II](https://www.livescience.com/tag/artemis-2) - [Pink moon](https://www.livescience.com/space/the-moon/how-to-catch-the-full-pink-moon-in-april-followed-by-a-blue-moon-in-may) - [China's pollution cut impacts Arctic](https://www.livescience.com/planet-earth/climate-change/chinas-huge-push-to-reduce-air-pollution-had-an-unexpected-consequence-in-the-arctic#mrfhud=true) - [Teenager's hives from water allergy](https://www.livescience.com/health/diagnostic-dilemma-teenagers-hives-turned-out-to-be-caused-by-rare-water-allergy) 1. [Space](https://www.livescience.com/space) 2. [Extraterrestrial Life](https://www.livescience.com/space/extraterrestrial-life) # Greatest Mysteries: Does Alien Life Exist? [News](https://www.livescience.com/news) By [Ker Than](https://www.livescience.com/author/ker-than) published August 6, 2007 When you purchase through links on our site, we may earn an affiliate commission. [Here’s how it works](https://www.livescience.com/about-live-science#section-affiliate-advertising-disclosure).  Greatest Mysteries: Does Alien Life Exist? Share - Copy link - [Facebook](https://www.facebook.com/sharer/sharer.php?u=https%3A%2F%2Fwww.livescience.com%2F4597-greatest-mysteries-alien-life-exist.html) - [X](https://twitter.com/intent/tweet?text=Greatest+Mysteries%3A+Does+Alien+Life+Exist%3F&url=https%3A%2F%2Fwww.livescience.com%2F4597-greatest-mysteries-alien-life-exist.html) - [Whatsapp](whatsapp://send?text=Greatest+Mysteries%3A+Does+Alien+Life+Exist%3F+https%3A%2F%2Fwww.livescience.com%2F4597-greatest-mysteries-alien-life-exist.html?fwa) - [Reddit](https://www.reddit.com/submit?url=https%3A%2F%2Fwww.livescience.com%2F4597-greatest-mysteries-alien-life-exist.html&title=Greatest+Mysteries%3A+Does+Alien+Life+Exist%3F) - [Pinterest](https://pinterest.com/pin/create/button/?url=https%3A%2F%2Fwww.livescience.com%2F4597-greatest-mysteries-alien-life-exist.html&media=https%3A%2F%2Fcdn.mos.cms.futurecdn.net%2F3MfrqPNeFdBp4Rp4FVYjSo.jpg) - [Flipboard](https://share.flipboard.com/bookmarklet/popout?title=Greatest+Mysteries%3A+Does+Alien+Life+Exist%3F&url=https%3A%2F%2Fwww.livescience.com%2F4597-greatest-mysteries-alien-life-exist.html) - [Email](mailto:?subject=I%20found%20this%20webpage&body=Hi,%20I%20found%20this%20webpage%20and%20thought%20you%20might%20like%20it%20https://www.livescience.com/4597-greatest-mysteries-alien-life-exist.html) Share this article Join the conversation [Follow us](https://google.com/preferences/source?q=livescience.com) Add us as a preferred source on Google Newsletter Sign up for the Live Science daily newsletter now Get the world’s most fascinating discoveries delivered straight to your inbox. *** By signing up, you agree to our [Terms of services](https:\/\/futureplc.com\/terms-conditions\/) and acknowledge that you have read our [Privacy Notice](https:\/\/futureplc.com\/privacy-policy\/). You also agree to receive marketing emails from us that may include promotions from our trusted partners and sponsors, which you can unsubscribe from at any time. You are now subscribed Your newsletter sign-up was successful *** Want to add more newsletters?  Delivered Daily Daily Newsletter Sign up for the latest discoveries, groundbreaking research and fascinating breakthroughs that impact you and the wider world direct to your inbox. Subscribe +  Once a week Life's Little Mysteries Feed your curiosity with an exclusive mystery every week, solved with science and delivered direct to your inbox before it's seen anywhere else. Subscribe +  Once a week How It Works Sign up to our free science & technology newsletter for your weekly fix of fascinating articles, quick quizzes, amazing images, and more Subscribe +  Delivered daily Space.com Newsletter Breaking space news, the latest updates on rocket launches, skywatching events and more\! Subscribe +  Once a month Watch This Space Sign up to our monthly entertainment newsletter to keep up with all our coverage of the latest sci-fi and space movies, tv shows, games and books. Subscribe +  Once a week Night Sky This Week Discover this week's must-see night sky events, moon phases, and stunning astrophotos. Sign up for our skywatching newsletter and explore the universe with us\! Subscribe + *** Join the club Get full access to premium articles, exclusive features and a growing list of member rewards. [Explore](https://www.livescience.com/membership) *** An account already exists for this email address, please log in. Subscribe to our newsletter **Editor's Note**: *We asked several scientists from various fields what they thought were the greatest mysteries today, and then we added a few that were on our minds, too. This article is one of 15 in LiveScience's "Greatest Mysteries" series running each weekday.* Life can be found in almost every nook and cranny of our planet Earth. Leaping, swimming, flying, sprinting, slithering, crawling or rooted firmly in place, organisms appear, die, and are replaced by new generations and new species. Whether a similar bounty of life exists elsewhere in the universe is one of the oldest and most tantalizing questions of science. Considering the wide breadth of the universe and the countless stars it contains, the odds would seem in favor of the answer being "yes." Latest Videos From Live Science "We are here, made of stardust. Therefore, it is at least possible that there are others," said Jill Tarter, director of the Center for SETI Research in California. **Hardy critters** But today's scientists hope to get beyond mere statistics to find something more substantial, and more edifying. Perhaps more than at any other time in history, scientists are optimistic that extraterrestrial life does exist, and that a firm confirmation can be had. Their hope is buoyed by recent discoveries of worlds beyond our [solar system](https://www.livescience.com/tag/solar-system) and new revelations recently learned about the hardiness of life here on our own planet. Sign up for the Live Science daily newsletter now Get the world’s most fascinating discoveries delivered straight to your inbox. By signing up, you agree to our [Terms of services](https:\/\/futureplc.com\/terms-conditions\/) and acknowledge that you have read our [Privacy Notice](https:\/\/futureplc.com\/privacy-policy\/). You also agree to receive marketing emails from us that may include promotions from our trusted partners and sponsors, which you can unsubscribe from at any time. "As we learn more about the diversity of life, particularly microbial life, we expand our definition of what life is and how life can exist in some very hostile (to humans) environments," said biologist Diana Northup of the University of New Mexico. Scientists have discovered microbes that are resilient to levels of heat, cold, salt, acidity, and radiation that would kill humans. Some of these so-called "[extremophiles](https://www.livescience.com/133-wild-extreme-creatures.html)" have been found thriving in complete darkness, in parched deserts and even miles below ground. All of this is good news for astrobiologists who dream of finding life beyond Earth's confines, as many of the extreme environments on our planet are thought to be the norm for other worlds. Earth's deserts, for example, have analogues on dry, dusty Mars. Saturn's moon Titan is a world of meandering [rivers and lakes](http://www.space.com/scienceastronomy/070103_titan_lakes.html), and beneath the icy crust of another Saturn moon, Enceladus, might lie environments resembling the frigid ocean depths of Earth. **Brave new worlds** Astrobiologists are also heartened by the recent explosion of new planets discovered outside our solar system. Since 1995, when astronomers spotted the first planet in orbit around another normal star, the number of extrasolar planets, or "exoplanets," has swelled to over 200. Scientists now know of more than 20 times more planets outside our solar system than in it. The majority of exoplanets discovered so far are bloated, fast-spinning gas giants, known as "hot Jupiters," that orbit extremely close to their stars and are thus probably unsuitable for life. But some exoplanets are wondrously Earth-like. Scientists recently spotted one world only 20.5 light-years away that lies within the habitable zone of its star—the region around a star where liquid water, and thus life, might exist. (It was later discovered the planet might be too hot for life, but another potentially habitable world in the same system was [quickly found](http://www.space.com/scienceastronomy/070618_mm_gliese_581d.html) to take its place.) With the ongoing refinement of current planet-finding techniques and the launch of new satellites, scientists expect not only to find a truly Earth-like world, but to also be able to probe it for life's [spectral fingerprints](http://www.space.com/scienceastronomy/earth_shine_021031.html) carried by a planet's reflected light. "Depending on what level of seeking and finding we are prepared to do, we could make discoveries in the next two decades that entirely change the way we understand the universe and life," said Margaret Turnbull, an astrobiologist at the Space Telescope Science Institute in Baltimore, Maryland. **SETI** Of course, there is always the chance that extraterrestrial life will [find us](http://www.space.com/searchforlife) first. Perhaps not in the form of a visiting UFO, but a radio transmission from an advanced alien civilization is still considered within the realm of possibility. "Mankind has achieved scientific-technological civilization only in the last 200 years or so, out of about 4.5 billion years of life on Earth," said Frank Wilczek, a Nobel-Prize winning physicist at MIT. "So it seems we ought to expect there to be many scientific-technological civilizations that have had many millions, or even billions, of years to develop." But even the discovery of one single-celled microbe on a distant world would be enough—enough to finally answer that age old question of "Are we alone in the universe?" and enough to change how humanity views itself. "The discovery of life forms inhabiting the unexplored extremities of our own planet, and eventually, the discovery of life on other planets, will bring into greater awareness the magnificence of a living universe," Turnball told LiveScience, "and, hopefully, a better understanding of ourselves." - [Another Great Mystery: How Many Species Exist on Earth?](https://www.livescience.com/4593-greatest-mysteries-species-exist-earth.html) - [Top 10 Most Intriguing Extrasolar Planets](http://www.space.com/scienceastronomy/extrasolar_planets.html) - [Life's Little Mysteries](http://www.space.com/php/video/player.php?video_id=b001024_sp_arecibo1) [Ker Than](https://www.livescience.com/author/ker-than) Latest in Extraterrestrial Life [ Extraterrestrial Life The government is very serious about UFOs. So why are researchers being stymied?](https://www.livescience.com/space/extraterrestrial-life/the-government-is-very-serious-about-ufos-so-why-are-researchers-being-stymied "The government is very serious about UFOs. So why are researchers being stymied?") [ Extraterrestrial Life Scientists squished microbes into a steel 'sandwich' — and made a profound discovery about life in space](https://www.livescience.com/space/extraterrestrial-life/scientists-squished-microbes-into-a-steel-sandwich-and-made-a-profound-discovery-about-life-in-space "Scientists squished microbes into a steel 'sandwich' — and made a profound discovery about life in space") [ Extraterrestrial Life SETI scientists reveal 100 'signals of interest' from collapsed Arecibo Observatory](https://www.livescience.com/space/extraterrestrial-life/scientists-study-100-possible-alien-radio-signals-from-collapsed-arecibo-observatory-ending-groundbreaking-21-year-search "SETI scientists reveal 100 'signals of interest' from collapsed Arecibo Observatory") [ Extraterrestrial Life Advanced alien civilizations could be communicating 'like fireflies' in plain sight, researchers suggest](https://www.livescience.com/space/extraterrestrial-life/advanced-alien-civilizations-could-be-communicating-like-fireflies-in-plain-sight-researchers-suggest "Advanced alien civilizations could be communicating 'like fireflies' in plain sight, researchers suggest") [ Extraterrestrial Life Scientists are debating a 70-year-old UFO mystery as new images come to light](https://www.livescience.com/space/extraterrestrial-life/no-easy-explanation-scientists-are-debating-a-70-year-old-ufo-mystery-as-new-images-come-to-light "Scientists are debating a 70-year-old UFO mystery as new images come to light") [ Extraterrestrial Life Is it aliens? Here's why that's the least important question about 3I/ATLAS.](https://www.livescience.com/space/extraterrestrial-life/is-it-aliens-heres-why-thats-the-least-important-question-about-3i-atlas "Is it aliens? Here's why that's the least important question about 3I/ATLAS.") Latest in News [ Space Exploration 'Trust us; you look amazing': Artemis II crewmembers share first message from space](https://www.livescience.com/space/space-exploration/trust-us-you-look-amazing-artemis-ii-crewmembers-share-first-message-from-space "'Trust us; you look amazing': Artemis II crewmembers share first message from space") [ Anatomy Scientists mapped all the nerves of the clitoris for the first time](https://www.livescience.com/health/anatomy/scientists-mapped-all-the-nerves-of-the-clitoris-for-the-first-time "Scientists mapped all the nerves of the clitoris for the first time") [ Space Exploration Artemis II officially leaves Earth's orbit on the way to the moon](https://www.livescience.com/space/space-exploration/artemis-ii-officially-leaves-earths-orbit-on-the-way-to-the-moon "Artemis II officially leaves Earth's orbit on the way to the moon") [ Physics & Mathematics New tweak to Einstein's relativity could transform our understanding of the Big Bang](https://www.livescience.com/physics-mathematics/a-new-tweak-to-einsteins-relativity-could-transform-our-understanding-of-the-big-bang "New tweak to Einstein's relativity could transform our understanding of the Big Bang") [ Space Exploration In photos: Artemis II's historic launch for the moon](https://www.livescience.com/space/space-exploration/in-photos-artemis-iis-historic-launch-for-the-moon "In photos: Artemis II's historic launch for the moon") [ Chemistry Chemists discover groundbreaking reaction that turns breadcrumbs into hydrogen](https://www.livescience.com/chemistry/chemists-make-hydrogen-from-breadcrumbs-in-groundbreaking-reaction-that-could-replace-some-fossil-fuels "Chemists discover groundbreaking reaction that turns breadcrumbs into hydrogen") LATEST ARTICLES 1. [](https://www.livescience.com/health/genetics/are-allergies-genetic "Are allergies genetic?") 1 [Are allergies genetic?](https://www.livescience.com/health/genetics/are-allergies-genetic) 2. 2 ['Trust us; you look amazing': Artemis II crewmembers share first message from space](https://www.livescience.com/space/space-exploration/trust-us-you-look-amazing-artemis-ii-crewmembers-share-first-message-from-space) 3. 3 [Homo habilis is the earliest named human. But is it even human?](https://www.livescience.com/archaeology/human-evolution/homo-habilis-is-the-earliest-named-human-but-is-it-even-human) 4. 4 [Scientists mapped all the nerves of the clitoris for the first time](https://www.livescience.com/health/anatomy/scientists-mapped-all-the-nerves-of-the-clitoris-for-the-first-time) 5. 5 [Rare 'sungrazer' comet MAPS could appear brighter than ever on Saturday: What to know](https://www.livescience.com/space/comets/rare-sungrazer-comet-maps-will-appear-brighter-than-ever-on-saturday-if-it-survives-a-dangerous-encounter-with-our-star) Live Science is part of Future US Inc, an international media group and leading digital publisher. [Visit our corporate site](https://futureplc.com/). [ Add as a preferred source on Google](https://google.com/preferences/source?q=livescience.com) - [About Us](https://www.livescience.com/about-live-science) - [Contact Future's experts](https://futureplc.com/contact/) - [Terms and conditions](https://futureplc.com/terms-conditions/) - [Privacy policy](https://futureplc.com/privacy-policy/) - [Cookies policy](https://futureplc.com/cookies-policy/) - [Accessibility Statement](https://futureplc.com/accessibility-statement/) - [Advertise with us](https://go.future-advertising.com/Live-Science-Media-Kit.html) - [Web notifications](https://www.livescience.com/how-to-turn-off-web-notifications-for-chrome-macos.html) - [Careers](https://futureplc.com/careers/) - [Editorial standards](https://www.livescience.com/editorial-standards) - [How to pitch a story to us](https://www.livescience.com/how-to-pitch-live-science) - [Do not sell or share my personal information](https://www.livescience.com/privacy-portal) © Future US, Inc. Full 7th Floor, 130 West 42nd Street, New York, NY 10036. Close Please login or signup to comment Please wait... Login Sign Up

 Greatest Mysteries: Does Alien Life Exist? **Editor's Note**: *We asked several scientists from various fields what they thought were the greatest mysteries today, and then we added a few that were on our minds, too. This article is one of 15 in LiveScience's "Greatest Mysteries" series running each weekday.* Life can be found in almost every nook and cranny of our planet Earth. Leaping, swimming, flying, sprinting, slithering, crawling or rooted firmly in place, organisms appear, die, and are replaced by new generations and new species. Whether a similar bounty of life exists elsewhere in the universe is one of the oldest and most tantalizing questions of science. Considering the wide breadth of the universe and the countless stars it contains, the odds would seem in favor of the answer being "yes." Latest Videos From Live Science "We are here, made of stardust. Therefore, it is at least possible that there are others," said Jill Tarter, director of the Center for SETI Research in California. **Hardy critters** But today's scientists hope to get beyond mere statistics to find something more substantial, and more edifying. Perhaps more than at any other time in history, scientists are optimistic that extraterrestrial life does exist, and that a firm confirmation can be had. Their hope is buoyed by recent discoveries of worlds beyond our [solar system](https://www.livescience.com/tag/solar-system) and new revelations recently learned about the hardiness of life here on our own planet. Get the world’s most fascinating discoveries delivered straight to your inbox. "As we learn more about the diversity of life, particularly microbial life, we expand our definition of what life is and how life can exist in some very hostile (to humans) environments," said biologist Diana Northup of the University of New Mexico. Scientists have discovered microbes that are resilient to levels of heat, cold, salt, acidity, and radiation that would kill humans. Some of these so-called "[extremophiles](https://www.livescience.com/133-wild-extreme-creatures.html)" have been found thriving in complete darkness, in parched deserts and even miles below ground. All of this is good news for astrobiologists who dream of finding life beyond Earth's confines, as many of the extreme environments on our planet are thought to be the norm for other worlds. Earth's deserts, for example, have analogues on dry, dusty Mars. Saturn's moon Titan is a world of meandering [rivers and lakes](http://www.space.com/scienceastronomy/070103_titan_lakes.html), and beneath the icy crust of another Saturn moon, Enceladus, might lie environments resembling the frigid ocean depths of Earth. **Brave new worlds** Astrobiologists are also heartened by the recent explosion of new planets discovered outside our solar system. Since 1995, when astronomers spotted the first planet in orbit around another normal star, the number of extrasolar planets, or "exoplanets," has swelled to over 200. Scientists now know of more than 20 times more planets outside our solar system than in it. The majority of exoplanets discovered so far are bloated, fast-spinning gas giants, known as "hot Jupiters," that orbit extremely close to their stars and are thus probably unsuitable for life. But some exoplanets are wondrously Earth-like. Scientists recently spotted one world only 20.5 light-years away that lies within the habitable zone of its star—the region around a star where liquid water, and thus life, might exist. (It was later discovered the planet might be too hot for life, but another potentially habitable world in the same system was [quickly found](http://www.space.com/scienceastronomy/070618_mm_gliese_581d.html) to take its place.) With the ongoing refinement of current planet-finding techniques and the launch of new satellites, scientists expect not only to find a truly Earth-like world, but to also be able to probe it for life's [spectral fingerprints](http://www.space.com/scienceastronomy/earth_shine_021031.html) carried by a planet's reflected light. "Depending on what level of seeking and finding we are prepared to do, we could make discoveries in the next two decades that entirely change the way we understand the universe and life," said Margaret Turnbull, an astrobiologist at the Space Telescope Science Institute in Baltimore, Maryland. **SETI** Of course, there is always the chance that extraterrestrial life will [find us](http://www.space.com/searchforlife) first. Perhaps not in the form of a visiting UFO, but a radio transmission from an advanced alien civilization is still considered within the realm of possibility. "Mankind has achieved scientific-technological civilization only in the last 200 years or so, out of about 4.5 billion years of life on Earth," said Frank Wilczek, a Nobel-Prize winning physicist at MIT. "So it seems we ought to expect there to be many scientific-technological civilizations that have had many millions, or even billions, of years to develop." But even the discovery of one single-celled microbe on a distant world would be enough—enough to finally answer that age old question of "Are we alone in the universe?" and enough to change how humanity views itself. "The discovery of life forms inhabiting the unexplored extremities of our own planet, and eventually, the discovery of life on other planets, will bring into greater awareness the magnificence of a living universe," Turnball told LiveScience, "and, hopefully, a better understanding of ourselves." - [Another Great Mystery: How Many Species Exist on Earth?](https://www.livescience.com/4593-greatest-mysteries-species-exist-earth.html) - [Top 10 Most Intriguing Extrasolar Planets](http://www.space.com/scienceastronomy/extrasolar_planets.html) - [Life's Little Mysteries](http://www.space.com/php/video/player.php?video_id=b001024_sp_arecibo1)