How can we know the size, composition, and atmospheric makeup of distant exoplanets? NASA explains the details in this Alien Atmospheres video.
By observing periodic variations in the parent star’s brightness and color, astronomers can indirectly determine an exoplanet’s distance from its star, its size, and its mass. But to truly understand an exoplanet astronomers must study its atmosphere, and they do so by splitting apart the parent star’s light during a planetary transit.
Watch more astronomy videos, including Measuring the Universe and The Hubble Ultra Deep Field.
via Boing Boing.
What did Mars look like 4 billion years ago? The team at NASA’s Conceptual Image Lab have an idea based on the existing evidence:
Billions of years ago when the Red Planet was young, it appears to have had a thick atmosphere that was warm enough to support oceans of liquid water - a critical ingredient for life. The animation shows how the surface of Mars might have appeared during this ancient clement period, beginning with a flyover of a Martian lake. The artist’s concept is based on evidence that Mars was once very different. Rapidly moving clouds suggest the passage of time, and the shift from a warm and wet to a cold and dry climate is shown as the animation progresses. The lakes dry up, while the atmosphere gradually transitions from Earthlike blue skies to the dusty pink and tan hues seen on Mars today.
The animation was released in anticipation of November 18th’s Cape Canaveral launch of MAVEN, Mars Atmosphere and Volatile Evolution mission. MAVEN will explore the planet’s lost atmosphere.
Previously: flying over a topographically accurate landscapes of Mars, and more NASA.
On its way to Mercury in August, 2005, eight years ago, Messenger Spacecraft took 358 images with its wide-angle camera over 24 hours, one Earth rotation. The images were brought together in this 13 second time lapse video. From APODVideos:
The spacecraft was 40,761 miles (65,598 kilometers) above South America when the camera started rolling on Aug. 2. It was 270,847 miles (435,885 kilometers) away from Earth - farther than the Moon’s orbit - when it snapped the last image on Aug. 3.
Farther than the Moon’s orbit. Lit beautifully in the darkness of space, this is what Earth looks like as you leave it.
You can also see Mercury spin. The smallest of our eight planets and the one closest to the Sun, Mercury is being well-documented by Messenger. After two years in orbit, it finished imaging 100% of the planet in early 2013.
Related watching: Mars spinning, and more planets.
This NASA Earth Science video, NASA Sees Photosynthesis From Space, is not only a lesson in how plants use light to make food for themselves, but also demonstrates how changing your perspective — in this case, looking at plants at a cellular level from hundreds of miles above the Earth — can change your understanding of the information.
Plants are often unable to absorb all the light that hits their leaves and chloroplasts. A small portion is re-emitted as fluorescence, it’s just that we can’t see the faint signal in broad daylight.
But satellites can. NASA shows you what plant fluorescence looks like from orbit. This kind of data is key to understanding the health of global vegetation.
More videos about plants, Earth, satellites, and different orbits await.