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.
A vortex ring is the phenomenon where a quantity of fluid or gas in a toroid (donut) shape, travels through a medium of fluid or gas, while spinning like a thick circular bracelet that is being rolled off of a person’s arm. (Except the spin is in the opposite direction as when a bracelet is rolled off in this way.)
What is beneath the world’s largest ice sheet? Compiled by the British Antarctic Survey and made from “millions of new measurements, including substantial data sets from NASA’s ICESat satellite and an airborne mission called Operation IceBridge,” this animated map of the changing Antarctic Ice Sheet reveals the bedrock terrain below with a level of detail never seen before.
It still didn’t get very bright; it was invisible to the naked eye. But with digital cameras and dark skies, snapping pictures of it was a matter of knowing where to aim, something photographer Colin Legg knows very well. From Perth, Australia, he captured this lovely time-lapse video of the asteroid moving past Earth right at the time of closest approach, 19:24 UTC. And he captured more than just DA14; there are some other surprises in the video, too. Make sure to set it to full-screen.
You can see DA14 sliding through the video from top to bottom on the left side of the frame. But right after the video starts, a meteor plummets through the field of view, leaving behind what’s called a persistent train—a trail of vaporized rock that can glow for several minutes.