Just as planets orbit Suns, galaxies can orbit each other. Now, NASA has created some unprecedented images of two such galaxies in the Milky Way's orbit, known as the Large and Small Magellanic Clouds (LMC and SMC). Here, you have an incredible view of these galaxies beneath the plane of the Milky Way.
According to NASA:
Astronomers at NASA's Goddard Space Flight Center in Greenbelt, Md., and the Pennsylvania State University in University Park, Pa., have used NASA's Swift satellite to create the most detailed surveys of the Large and Small Magellanic Clouds, the two closest major galaxies, in ultraviolet light.
Thousands of images were assembled into seamless portraits of the main body of each galaxy to produce the highest-resolution surveys of the Magellanic Clouds at ultraviolet wavelengths. The project was proposed by Stefan Immler, an astronomer at Goddard.
The Large and Small Magellanic Clouds, or LMC and SMC for short, lie about 163,000 and 200,000 light-years away, respectively, and orbit each other as well as our own Milky Way galaxy.
Compared to the Milky Way, the LMC has about one-tenth its physical size and only 1 percent of its mass. The SMC is only half the size of the LMC and contains about two-thirds of its mass.
The new images reveal about a million ultraviolet sources within the LMC and about 250,000 in the SMC.
Viewing in the ultraviolet allows astronomers to suppress the light of normal stars like the sun, which are not very bright at these higher energies, and provide a clearer picture of the hottest stars and star-formation regions.
Only Swift's Ultraviolet/Optical Telescope, or UVOT, is capable of producing such high-resolution wide-field multi-color surveys in the ultraviolet. The LMC and SMC images range from 1,600 to 3,300 angstroms, UV wavelengths largely blocked by Earth's atmosphere.
The Large and Small Magellanic Clouds are readily visible from the Southern Hemisphere as faint, glowing patches in the night sky. The galaxies are named after Ferdinand Magellan, the Portuguese explorer who in 1519 led an expedition to sail around the world. He and his crew were among the first Europeans to sight the objects.
In this video, Immler explains what you're seeing, as well as how these images were created with multiple exposures that register different wavelengths of light.
Understanding how other galaxies function helps us understand our own galaxy, including how new stars form in it.
There are half a dozen beautiful new images of the LMC and SMC on NASA's website. Download them for your new favorite desktop wallpaper. We are especially fond of this one, of the winningly-named Tarantula Nebula in the LMC.