Exoplanets Multimedia


A series of four disks – illustrations of how Earth might have looked from afar at different epochs – starts on the right with a red and brown molten world just after formation, a cooling Earth with oceans and continents 4.3 billion years ago, a possibly green-tinged Earth inhabited by the earliest life 3.7 billion years ago, and Earth today, blue, green, and white, with oceans, continents, and ice caps.First disk:Earth FormsOur world accreted from a Sun-circling disk of gas and dust about 4.5 billion years ago – then collided with a Mars-sized body about 50 million years later, leading to formation of the Moon.Second disk:Earth CoolsThe surface cooled rapidly, achieving a hot but solid crust, with early oceans and impact basins filled with lava by about 4.3 billion years ago.Third disk:Life BeginsThe earliest life-forms might have appeared during the archean Era some 3.7 billion years ago – or even earlier. Oceans could have been tinged green by iron ions. Life-forms relying on oxygen, and an oxygenated atmosphere, did not arise until much later.Fourth disk:Earth TodayOur world of abundant life, with its oxygen-rich atmosphere, likely would be recognized as habitable from many light-years away. But the presence of oxygen might not have been detectable even as recently as 800-500 million years ago.

Evolving Earth

Our planet passed through stages to become a habitable world.

An infographic is headlined, Chemical Reactions Caused by Starlight. It shows an illustration of the surface of a reddish exoplanet beneath its star. Light from the star shines into the chemical reaction portrayed in the graphic. Here, you can see molecules interacting and forming new compounds.Photons from WASP-39 b’s nearby star interact with abundant water molecules (H2O) in the exoplanet’s atmosphere.The water splits into hydrogen atoms (H) and hydroxide (OH).The molecules continue to interact in the atmosphere.Hydrogen sulfide reacts with hydrogen and hydroxide in a series of steps. The process strips hydrogen and adds oxygen, eventually producing sulfur dioxide.

Infographic: Chemical Reactions Caused by Starlight

Analysis of the exoplanet WASP-39b identified the sulfur dioxide. Its presence can only be explained by photocemistry.

Video: Lifting the Veil on Exoplanet Clouds

NASA's James Webb Space Telescope will reveal secrets of clouds in the atmospheres of exoplanets – planets beyond our solar…

colorful retro illustration of the TESS space telescope and planetary systems

El Telescopio Espacial TESS

TESS, el "Transiting Exoplanet Survey Satellite", se lanzó en 2018 para descubrir planetas pequeños que orbitan estrellas brillantes en todo…

colorful retro illustration of the TESS space telescope and planetary systems

TESS Space Telescope Poster

NASA’s latest exoplanet hunter, launched in 2018, has also made astounding astronomical discoveries with its almost full-sky view.


The orbit of a planet can cause a star to wobble around in space in relation to nearby stars in…

Transit Method Single Planet

When a planet passes directly between a star and its observer, it dims the star's light by a measurable amount.…

Transit Method Different Planet Sizes

When a planet passes directly between a star and its observer, it dims the star's light by a measurable amount.…

Direct Imaging

Astronomers can take pictures of exoplanets by removing the overwhelming glare of the stars they orbit.

Radial Velocity

Orbiting planets cause stars to wobble in space, changing the color of the light astronomers observe.

Exoplanet light curve

An exoplanet passes in front of its parent star, then passes behind – creating a “light curve” that can be…

Artist's rendering of exoplanet surface

Marble in the Sky: the Hunt for Another Earth

In this artist's concept, a distant, life-bearing world orbits two stars instead of one, seen from the surface in a…