Thomas Goertel (Space Telescope Science Institute)

Centaurus A, also known as NGC 5128, is a galaxy near our own Milky Way. Astronomers have shown that it is in the process of consuming another, smaller galaxy. This interaction appears to be funneling galactic material into a supermassive black hole hidden at the center of Centaurus A. This movie combines observational data with artistic imagination to show what the space near the black hole might look like.

Active galactic nuclei

Using infrared instruments on the Hubble Space Telescope, astronomers have observed a twisted disk of hot gas swept up in the gravitational whirlpool of Centaurus A. The supermassive black hole is hundreds of millions of times more massive than our Sun and has assembled a twisted disk of super-hot gas around it. Like a wheel wobbling around a loose axle, this active galactic nucleus fires an energetic jet of material into space. This ejected light glows in X-rays and radio waves and is blasted from the black hole in excess of 10 million miles per hour.

Gordon Myers

Melania Brolis (Osservatorio Astronomico)

Stars form in interstellar clouds of gas and dust, trillions of miles across. When the random motions of the gas cause a small part of the cloud to become denser than the rest of the cloud, gas begins to collapse, contract, and heat up. At temperatures of millions of degrees, nuclear fusion begins at the center of the gas clump and a star is born. In some clouds, dozens or hundreds of stars form together creating a star cluster. This movie shows images, taken with various telescopes, of one star that has formed in the Orion Nebula star cluster.

Star formation

The movie takes us on a journey from the night sky to the Orion Nebula, a star forming region at the belt of the constellation Orion. Each image in the sequence reveals more detail, as seen by the Hubble Space Telescope. Near the final image, we see newly hatched stars swaddled in teardrop-shaped cocoons of gas called proplyds. These are the remnants of the protostellar gas clouds that collapsed to form these new stars. Finally, we look closely at a new star, not quite as bright as our own Sun, with what appears to be a dark, gaseous protoplanetary disk around it. Could this be a new solar system being born?

Austin Reiter

Phil James (University of Toledo), Todd Clancy (STScI), Steven Lee (University of Colorado), and NASA/STScI

These images appear to have been taken from above the Martian pole, but they were taken with the Hubble Space Telescope from Earth orbit. Each frame in this animation was constructed from three separate images taken in October 1996 and in January and March of 1997. The first image corresponds to early spring in the Northern Hemisphere when the polar ice cap extends to about 60° north latitude. The second image was taken in mid-spring and shows a smaller ice cap resulting from increasing atmospheric warming. The final image from early summer on Mars shows a vastly reduced polar cap; much of the carbon dioxide ice has sublimated, revealing the terrain beneath.

Martian Seasons

Mars has a cycle of seasons that is similar to Earth. The reason for this is that both planets are similarly tilted on their rotational axes: a 23.5° tilt for Earth and a 25.2° tilt for Mars. Because Mars takes about twice as long to orbit the Sun, each Martian season is about twice as long as the corresponding season on Earth. In addition, the Martian atmosphere is much thinner than Earth's atmosphere, so there is little insulation to protect the Martian atmosphere from temperature shifts due to changes on the surface or in the Mars-Sun distance.

The Mars-Sun distance

The Mars-Sun distance changes by 20 percent over the course of the year. When Mars is closest to the Sun, it is summer in the Southern Hemisphere and temperatures are up 35° F, producing dust storms that swirl around the planet and absorb sunlight, further heating the atmosphere. When Mars is farthest from the Sun, water-ice clouds reduce atmospheric temperatures. The dust particles in the atmosphere seed these clouds, then fall to the ground. Competition between cloud cooling and dust heating drives annual as well as short-term climate changes on Mars.

Ellen Cohen