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[Blogs](https://www.nasa.gov/nasa-blogs/) - [Newsletters](https://www.nasa.gov/newsletters/) - [Social Media](https://www.nasa.gov/socialmedia/) - [Media Resources](https://www.nasa.gov/news/nasa-media-contacts/) [Multimedia](https://science.nasa.gov/multimedia/) - [Images](https://www.nasa.gov/images/) - [Videos on NASA+](https://www.nasa.gov/plus/) - [Interactives](https://www.nasa.gov/nasa-interactive-features/) - [NASA Apps](https://www.nasa.gov/apps/) - [Podcasts](https://www.nasa.gov/podcasts/) - [e-Books](https://www.nasa.gov/ebooks/) - [STEM Multimedia](https://www.nasa.gov/learning-resources/search/?terms=8058%2C8059%2C8061%2C8062%2C8068) ### Highlights [ 7 min read NASA Releases Artemis II Moon Mission Launch Countdown article 1 week ago](https://www.nasa.gov/general/nasa-releases-artemis-ii-moon-mission-launch-countdown/) [ 4 min read Preparing for Artemis II: Training for a Mission Around the Moon article 2 months ago](https://www.nasa.gov/centers-and-facilities/johnson/preparing-for-artemis-ii-training-for-a-mission-around-the-moon/) [ 7 min read To Protect Artemis II Astronauts, NASA Experts Keep Eyes on Sun article 3 weeks ago](https://science.nasa.gov/missions/artemis/artemis-2/to-protect-artemis-ii-astronauts-nasa-experts-keep-eyes-on-sun/) ### Highlights [ 10 min read NASA Answers Your Most Pressing Artemis II Questions article 1 day ago](https://www.nasa.gov/missions/nasa-answers-your-most-pressing-artemis-ii-questions/) [ 1 min read Artemis II Podcast Series article 1 week ago](https://www.nasa.gov/artemispodcast/) [ 7 min read NASA Releases Artemis II Moon Mission Launch Countdown article 1 week ago](https://www.nasa.gov/general/nasa-releases-artemis-ii-moon-mission-launch-countdown/) ### Highlights [ 4 min read Barents Sea Tied to Low Arctic Sea Ice article 3 days ago](https://science.nasa.gov/earth/earth-observatory/barents-sea-tied-to-low-arctic-sea-ice/) [ 3 min read Réunion Island Lava Reaches the Sea article 4 days ago](https://science.nasa.gov/earth/earth-observatory/reunion-island-lava-reaches-the-sea/) [ 3 min read March of the Harmattan article 5 days ago](https://science.nasa.gov/earth/earth-observatory/march-of-the-harmattan/) ### Highlights [ 5 min read Meet NASA’s New Artemis II Science Officers article 2 days ago](https://science.nasa.gov/missions/artemis/meet-nasas-new-artemis-ii-science-officers/) [ 1 min read Impact Flash! article 4 days ago](https://science.nasa.gov/citizen-science/impact-flash/) [ 4 min read Helio and You: The Sun, Solar Wind, and Earth as a Connected System article 4 days ago](https://science.nasa.gov/helio-and-you-the-sun-solar-wind-and-earth-as-a-connected-system/) ### Highlights [ 6 min read NASA Webb, Hubble Share Most Comprehensive View of Saturn to Date article 2 weeks ago](https://science.nasa.gov/missions/webb/nasa-webb-hubble-share-most-comprehensive-view-of-saturn-to-date/) [ 5 min read NASA-JAXA’s XRISM Telescope Clocks Hot Wind of Galaxy M82 article 2 weeks ago](https://science.nasa.gov/missions/xrism/nasa-jaxas-xrism-telescope-clocks-hot-wind-of-galaxy-m82/) [ 4 min read NASA’s Hubble Revisits Crab Nebula to Track 25 Years of Expansion article 2 weeks ago](https://science.nasa.gov/missions/hubble/nasas-hubble-revisits-crab-nebula-to-track-25-years-of-expansion/) ### Highlights [ 5 min read Meet NASA’s New Artemis II Science Officers article 2 days ago](https://science.nasa.gov/missions/artemis/meet-nasas-new-artemis-ii-science-officers/) [ 4 min read Barents Sea Tied to Low Arctic Sea Ice article 3 days ago](https://science.nasa.gov/earth/earth-observatory/barents-sea-tied-to-low-arctic-sea-ice/) [ 2 min read Georgia Peterson article 4 days ago](https://www.nasa.gov/people/georgia-peterson/) ### Highlights [ 4 min read NASA Selects Finalists in Student Aircraft Maintenance Competition article 2 weeks ago](https://www.nasa.gov/aeronautics/nasa-selects-finalists-in-student-aircraft-maintenance-competition/) [ 2 min read NASA’s X-59 Experimental Supersonic Aircraft Makes Second Flight article 2 weeks ago](https://www.nasa.gov/missions/quesst/nasas-x-59-experimental-supersonic-aircraft-makes-second-flight/) [ 2 min read NASA Simulations Improve Artemis II Launch Environment article 2 weeks ago](https://www.nasa.gov/aeronautics/artemis-sls-launch-sim/) ### Highlights [ 3 min read Fires Tear Through Nebraska Grasslands article 6 days ago](https://science.nasa.gov/earth/earth-observatory/fires-tear-through-nebraska-grasslands/) [ 3 min read I Am Artemis: Erik Richards article 1 week ago](https://www.nasa.gov/missions/artemis/i-am-artemis/i-am-artemis-erik-richards/) [ 6 min read NASA Tech and Science Bound for Low Earth Orbit on Commercial Launch article 1 week ago](https://www.nasa.gov/directorates/stmd/nasa-tech-and-science-bound-for-low-earth-orbit-on-commercial-launch/) ### Highlights [ 1 min read Join the Artemis Mission to the Moon article 5 months ago](https://www.nasa.gov/learning-resources/join-artemis/) ### Highlights [ 11 min read NASA’s Artemis II Moon Mission Daily Agenda article 3 weeks ago](https://www.nasa.gov/missions/artemis/nasas-artemis-ii-moon-mission-daily-agenda/) [ 4 min read Preparing for Artemis II: Training for a Mission Around the Moon article 2 months ago](https://www.nasa.gov/centers-and-facilities/johnson/preparing-for-artemis-ii-training-for-a-mission-around-the-moon/) [ 3 min read Track NASA’s Artemis II Mission in Real Time article 1 month ago](https://www.nasa.gov/missions/artemis/artemis-2/track-nasas-artemis-ii-mission-in-real-time/) ### Highlights [ 11 min read La NASA anuncia la cobertura de la misión lunar Artemis II article 2 weeks ago](https://www.nasa.gov/es/la-nasa-anuncia-la-cobertura-de-la-mision-lunar-artemis-ii/) [ 15 min read Agenda diaria de la misión a la Luna de Artemis II de la NASA article 3 weeks ago](https://www.nasa.gov/es/agenda-diaria-de-la-mision-a-la-luna-de-artemis-ii-de-la-nasa/) [ 6 min read La NASA refuerza Artemis: añade una misión y perfecciona su arquitectura general article 1 month ago](https://www.nasa.gov/humans-in-space/astronauts/la-nasa-refuerza-artemis-anade-una-mision-y-perfecciona-su-arquitectura-general/) Explore This Section 1. […](https://science.nasa.gov/) 2. [Exoplanets](https://science.nasa.gov/exoplanets/) 3. Are We Alone? - [Exoplanets Home](https://science.nasa.gov/exoplanets/) - Overview - [Exoplanet Facts](https://science.nasa.gov/exoplanets/facts/) - [Types of Exoplanets](https://science.nasa.gov/exoplanets/planet-types/) - [Stars](https://science.nasa.gov/exoplanets/stars/) - [What is the Universe](https://science.nasa.gov/exoplanets/what-is-the-universe/) - Search for Life - [The Big Questions](https://science.nasa.gov/exoplanets/big-questions/) - [Are We Alone?](https://science.nasa.gov/exoplanets/search-for-life/) - [Can We Find Life?](https://science.nasa.gov/exoplanets/can-we-find-life/) - [The Habitable Zone](https://science.nasa.gov/exoplanets/habitable-zone/) - [Why We Search](https://science.nasa.gov/exoplanets/why-we-search/) - [Target Star Catalog](https://science.nasa.gov/exoplanets/target-star-catalog/) - Discoveries - [Discoveries Dashboard](https://science.nasa.gov/exoplanets/discoveries-dashboard/) - [How We Find and Characterize](https://science.nasa.gov/exoplanets/how-we-find-and-characterize/) - [Missions](https://science.nasa.gov/exoplanets/missions/) - [People](https://science.nasa.gov/exoplanets/people/) - [Exoplanet Catalog](https://science.nasa.gov/exoplanets/exoplanet-catalog/) - Immersive - [The Exoplaneteers](https://science.nasa.gov/exoplanets/immersive/the-exoplaneteers/) - [Exoplanet Travel Bureau](https://science.nasa.gov/exoplanets/immersive/exoplanet-travel-bureau/) - [5 Ways to Find a Planet](https://science.nasa.gov/exoplanets/how-we-find-and-characterize/) - [Strange New Worlds](https://science.nasa.gov/exoplanets/immersive/strange-new-worlds/) - [Universe of Monsters](https://science.nasa.gov/exoplanets/immersive/universe-of-monsters/) - [Galaxy of Horrors](https://science.nasa.gov/exoplanets/immersive/galaxy-of-horrors/) - [‘The Lost Universe’ game](https://science.nasa.gov/mission/hubble/multimedia/online-activities/the-lost-universe/) - News - [Stories](https://science.nasa.gov/exoplanets/stories) - [Features](https://science.nasa.gov/exoplanets/exoplanet-features/) - [Blog](https://science.nasa.gov/exoplanets/exoplanets-blog/) - Resources - [Multimedia](https://science.nasa.gov/exoplanets/multimedia/) - [Glossary](https://science.nasa.gov/exoplanets/glossary/) - [Eyes on Exoplanets](https://eyes.nasa.gov/apps/exo/) - [Get Involved](https://science.nasa.gov/exoplanets/citizen-science/) - [Exoplanet Watch](https://science.nasa.gov/citizen-science/exoplanet-watch/exoplanet-watch-overview/) - For Scientists - [Exoplanet Exploration Program](https://science.nasa.gov/astrophysics/programs/exep/) - [NASA Exoplanet Science Institute](https://nexsci.caltech.edu/) # Are We Alone?  ## Contents - [Just Getting Started](https://science.nasa.gov/exoplanets/search-for-life/#h-the-search-for-life-beyond-earth-is-really-just-getting-started-but-science-has-an-encouraging-early-answer-there-are-plenty-of-planets-in-the-galaxy-many-with-similarities-to-our-own-but-what-we-don-t-know-fills-volumes) - [More Questions than Answers](https://science.nasa.gov/exoplanets/search-for-life/#h-more-questions-than-answers) - [Where Is Everybody?](https://science.nasa.gov/exoplanets/search-for-life/#h-where-is-everybody) ## Just Getting Started **The search for life beyond Earth is really just getting started, but science has an encouraging early answer: there are plenty of planets in the galaxy, many with similarities to our own. But what we don’t know fills volumes.** Observations from the ground and from space have confirmed [thousands of planets beyond our solar system](https://science.nasa.gov/exoplanets/discoveries-dashboard/). Our galaxy likely holds at least 100 billion. But so far, we have no evidence of life beyond Earth. Is life in the cosmos easily begun, and commonplace? Or [is it incredibly rare?](https://science.nasa.gov/universe/exoplanets/is-earth-an-oddball/) How big is the Milky Way galaxy? Make the jump to light-years as we cruise through our galaxy. Video **NASA/JPL-Caltech** ## More Questions than Answers In the thousands of years humanity has been contemplating the cosmos, we are the first people to know one thing for sure: [The stars beyond our Sun are teeming with planets](https://science.nasa.gov/universe/exoplanets/what-in-the-world-is-an-exoplanet/). They come in many varieties, and a good chunk of them are [around the size of Earth](https://science.nasa.gov/universe/exoplanets/rocky-habitable-sizing-up-a-galaxy-of-planets/). Like most scientific questions, though, getting an answer to this one just breeds more questions: Which, if any, of these exoplanets harbors some form of life? How quickly does life get its start? And how long does it last? [](https://assets.science.nasa.gov/dynamicimage/assets/science/astro/exo-explore/internal_resources/1770/Trappist-1_Planets_shown_in_a_row_next_to_their_star.jpeg?w=1600&h=900&fit=clip&crop=faces%2Cfocalpoint) This artist's concept allows us to imagine what it would be like to stand on the surface of the exoplanet TRAPPIST-1f, located in the TRAPPIST-1 system in the constellation Aquarius, as of Feb 2017. ## Where Is Everybody? The universe's eerie silence has its own name – the ["Fermi paradox."](https://www.nasa.gov/feature/nasa-is-taking-a-new-look-at-searching-for-life-beyond-earth) Physicist Enrico Fermi famously posed the question: "Where is everybody?" Even at slow travel speeds, the universe's billions of years of existence allow plenty of time for intelligent, technological lifeforms to traverse the galaxy. Why, then, is the cosmos so quiet? Meanwhile, exoplanet discoveries over the past two decades have filled in a few of the terms in the much-debated [Drake Equation](https://science.nasa.gov/universe/exoplanets/are-we-alone-in-the-universe-revisiting-the-drake-equation/) – a chain of numbers that might one day tell us how many intelligent civilizations we can expect to find. Most of its terms remain blank – the fraction of planets with life, with intelligent life, with detectable technology – but the equation itself suggests we might one day arrive at an answer. It feels at least a little more hopeful than Fermi's silence. We stand at a crossroads in the search for life. We've found thousands of planets in our Milky Way galaxy, a large fraction of them in Earth's size range and orbiting in their stars' "habitable zones" – the distance from the star at which liquid water *could* exist on the surface. We know the galaxy likely holds trillions of planets. Our telescopes in space and on the ground, and our remote-sensing technology, grow ever more powerful. Yet so far, the only life we know of is right here at home. For the moment, we're staring into the void, hoping someone is staring back. [](https://assets.science.nasa.gov/dynamicimage/assets/science/astro/exo-explore/internal_resources/1771/Drake_equation_illustration.jpeg?w=1280&h=638&fit=clip&crop=faces%2Cfocalpoint) Revised Drake equation. 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## Just Getting Started **The search for life beyond Earth is really just getting started, but science has an encouraging early answer: there are plenty of planets in the galaxy, many with similarities to our own. But what we don’t know fills volumes.** Observations from the ground and from space have confirmed [thousands of planets beyond our solar system](https://science.nasa.gov/exoplanets/discoveries-dashboard/). Our galaxy likely holds at least 100 billion. But so far, we have no evidence of life beyond Earth. Is life in the cosmos easily begun, and commonplace? Or [is it incredibly rare?](https://science.nasa.gov/universe/exoplanets/is-earth-an-oddball/) How big is the Milky Way galaxy? Make the jump to light-years as we cruise through our galaxy. Video **NASA/JPL-Caltech** ## More Questions than Answers In the thousands of years humanity has been contemplating the cosmos, we are the first people to know one thing for sure: [The stars beyond our Sun are teeming with planets](https://science.nasa.gov/universe/exoplanets/what-in-the-world-is-an-exoplanet/). They come in many varieties, and a good chunk of them are [around the size of Earth](https://science.nasa.gov/universe/exoplanets/rocky-habitable-sizing-up-a-galaxy-of-planets/). Like most scientific questions, though, getting an answer to this one just breeds more questions: Which, if any, of these exoplanets harbors some form of life? How quickly does life get its start? And how long does it last? ## Where Is Everybody? The universe's eerie silence has its own name – the ["Fermi paradox."](https://www.nasa.gov/feature/nasa-is-taking-a-new-look-at-searching-for-life-beyond-earth) Physicist Enrico Fermi famously posed the question: "Where is everybody?" Even at slow travel speeds, the universe's billions of years of existence allow plenty of time for intelligent, technological lifeforms to traverse the galaxy. Why, then, is the cosmos so quiet? Meanwhile, exoplanet discoveries over the past two decades have filled in a few of the terms in the much-debated [Drake Equation](https://science.nasa.gov/universe/exoplanets/are-we-alone-in-the-universe-revisiting-the-drake-equation/) – a chain of numbers that might one day tell us how many intelligent civilizations we can expect to find. Most of its terms remain blank – the fraction of planets with life, with intelligent life, with detectable technology – but the equation itself suggests we might one day arrive at an answer. It feels at least a little more hopeful than Fermi's silence. We stand at a crossroads in the search for life. We've found thousands of planets in our Milky Way galaxy, a large fraction of them in Earth's size range and orbiting in their stars' "habitable zones" – the distance from the star at which liquid water *could* exist on the surface. We know the galaxy likely holds trillions of planets. Our telescopes in space and on the ground, and our remote-sensing technology, grow ever more powerful. Yet so far, the only life we know of is right here at home. For the moment, we're staring into the void, hoping someone is staring back. **Next: We don't have a universally accepted definition of life itself, [so can we find life?](https://science.nasa.gov/exoplanets/can-we-find-life/)** Keep Exploring ## Discover More Topics From NASA