Is there life elsewhere?

What astrobiology asks

Astrobiology is the science of life in the universe: how it began on Earth, where else it might exist, and how we could recognize it. It brings together astronomers, biologists, chemists and geologists.

The honest starting point is that, as of 2026, scientists have not confirmed life anywhere beyond Earth. Not microbes, not fossils, not signals. Every claim so far has either been explained by non-living processes or is still under study.

That does not mean the answer is no. It means the search is young, and we only have one example of life to learn from.

What life needs

Every living thing on Earth uses liquid water as the place where its chemistry happens. Water dissolves many substances and lets molecules move and react.

Life also needs energy, from sunlight or from chemical reactions such as those at hot vents on the seafloor, where whole ecosystems thrive in total darkness. And it needs building blocks, mainly carbon combined with hydrogen, nitrogen, oxygen, phosphorus and sulfur.

Scientists stay open to life that might work differently, but these needs give a practical guide: "follow the water" and look for energy and organic chemistry.

Candidates in our Solar System

Mars once had rivers, lakes and a thicker atmosphere, so microbes could have lived there billions of years ago. In 2025, NASA reported that a rock sampled by the Perseverance rover in 2024 holds patterns that could be a potential biosignature. NASA stressed that non-living chemistry might also explain them, and that the sample would need study in labs on Earth to settle the question.

Europa, a moon of Jupiter, hides a salty ocean beneath its ice, probably holding more water than all of Earth's oceans. NASA's Europa Clipper, launched in 2024, is due to arrive in 2030 to study whether that ocean could support life; it will not search for life directly.

Enceladus, a small moon of Saturn, sprays jets of water from an underground ocean. The Cassini spacecraft flew through them and found salts, organic molecules and signs of hydrothermal activity.

Titan, Saturn's largest moon, has lakes of liquid methane and ethane, a thick hazy atmosphere and likely a water ocean deep inside. NASA's Dragonfly rotorcraft is planned to launch in 2028 and explore its surface.

Biosignatures: clues to look for

A biosignature is any sign that life is or was present: a fossil, a mineral pattern, a mix of gases, or a molecule that living things tend to make.

On Earth, oxygen and methane together in the air are a strong hint of life, because they react and would disappear unless something kept replacing them. The James Webb Space Telescope can now study the atmospheres of some planets around other stars.

The hard part is ruling out non-living explanations. Volcanoes, starlight and rock chemistry can mimic many signs, so scientists treat any single detection with caution until it is confirmed in several independent ways.

The Drake equation in plain words

In 1961, astronomer Frank Drake wrote down a way to think about how many civilizations in our galaxy might be sending out signals right now. It multiplies a chain of factors.

In everyday words: how many stars form each year, what share have planets, how many of those planets suit life, how often life actually starts, how often it becomes intelligent, how often that intelligence builds technology we could detect, and how long such a civilization keeps sending signals.

Astronomers now know the first few factors quite well; most stars have planets. The later ones are almost pure guesses, so the answer can range from far less than one to millions. The equation is a tool for organizing the question, not a way to calculate a firm number.

SETI and the Fermi paradox

SETI, the Search for Extraterrestrial Intelligence, listens for radio or laser signals that could only come from technology. It began with Drake's Project Ozma in 1960 and continues with modern projects that scan millions of radio channels. No confirmed signal has been found.

The famous 1977 "Wow!" signal was a strong, brief radio burst that was never repeated, so it cannot be counted as evidence.

Physicist Enrico Fermi is credited with asking, around 1950, "Where is everybody?" The galaxy is billions of years old and holds billions of planets, so if civilizations are common, some should have spread or left signs. Proposed answers include that life is rare, that civilizations do not last, that distances are too great, or that we have simply not looked long or carefully enough.

How you can take part

You can follow results from Perseverance, Europa Clipper and the Webb telescope on NASA and ESA websites, where new findings are explained as they come out.

Citizen science projects let volunteers help sort telescope data, for example in searches for new exoplanets. On a clear evening you can also spot Mars, Jupiter and Saturn with your own eyes, the worlds where some of these searches take place.