NASA Hubble Image: A Chance Alignment Between Galaxies

The Hubble Space Telescope shows a rare view of a pair of overlapping galaxies, called NGC 3314.

The two galaxies look as if they are colliding, but they are actually separated by tens of millions of light-years, or about ten times the distance between our Milky Way and the neighbouring Andromeda galaxy.

The chance alignment of the two galaxies, as seen from Earth, gives a unique look at the silhouetted spiral arms in the closer face-on spiral, NGC 3314A.

Image Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration, and W. Keel (University of Alabama)

Planet Triple Play: Saturn, Mars and Venus Appear Together

SPACE.com -- Planet Triple Play: Saturn, Mars and Venus Appear Together

If you live in the northern hemisphere, go out any night this week an hour or so after sunset and look at the western sky to catch a planetary triple play starring Venus, Saturn and Mars.

The first thing skywatchers will see — weather permitting — is the brilliant planet Venus, slightly north of west, in the constellation Gemini. Look for Gemini's twin first magnitude stars, Pollux and Castor, just above Venus.

As the sky gets darker, the planet Mars can be spotted to Venus' left as it appears in the constellation Leo very close to the bright, first magnitude star Regulus. Further still to the left will be Saturn shining in the western part of the constellation Virgo.

This sky map shows how to spot all three planets as they appear across a 71-degree angle in the night sky. For comparison, your closed fist held at arm's length covers about 5 degrees of arc in the sky.

Venus, Mars and Saturn are all currently appearing slightly north of the ecliptic, the path the sun appears to follow over the year, shown in green in the sky map. [More Mars photos.]

Note the positions of these three planets in relation to the bright background stars, because they are beginning an interesting journey which you will be able to follow over the next two months.

In early July, Venus will have moved rapidly to the left, crossing Cancer into Leo so that now it is next to the star Regulus. Mars, meanwhile, will have moved somewhat to the left. Saturn appears to have hardly moved at all.

By then, the three planets will now cover only 37 degrees in the sky, only half the spread they showed in early June.

A month after this, in the first week of August, the planets will be crowded into a 7-degree angle, and Mars will now be to the left of Saturn in Virgo. Venus, too, will have moved into Virgo.

All three will fit comfortably in the viewing field of a small pair of binoculars.

By August, Venus will still be brilliant, but both Saturn and Mars will have faded so that they just barely reach first magnitude. That's because Saturn and Mars are getting farther away from Earth, while Venus is getting closer.

ESA: Phobos and Deimos, Martian Moon Duo, in alignment

Phobos and Deimos raw (left panel) and processed images (right panel). Phobos rests in the foreground of the image with Deimos behind. Deimos was more than twice as far from the camera.

Credit: ESA/DLR/FU Berlin (G. Neukum).

For the very first time, the Martian moons Phobos and Deimos have been caught on camera together. ESA's Mars Express orbiter took these pioneering images last month. Apart from their 'wow' factor, these unique images will help the HRSC team validate and refine existing orbit models of the two moons.

The images were acquired with the Super Resolution Channel (SRC) of the High Resolution Stereo Camera (HRSC). The camera took 130 images of the moons on 5 November at 9:14 CET over period of 1.5 minutes at intervals of 1s, speeding up to 0.5-s intervals toward the end. The image resolution is 110 m/pixel for Phobos and 240 m/pixel for Deimos - Deimos was more than twice as far from the camera.

The Super Resolution Channel of the HRSC uses an additional lens, which has a very narrow field of view of just 0.5 degree, providing four times the resolution of the HRSC color stereo channel.

Phobos, the larger of the two moons, orbits closer to the Red Planet, circling it every 7 hours and 39 minutes. It travels faster relative to Mars than the Moon relative to Earth. It was 11,800 km from Mars Express when the images were taken. Deimos was 26,200 km away.

It is not often that both Martian moons are located directly in front of the camera, lined up one behind the other. The chance to image both moons together came on 5 November 2009 when the viewing geometry was especially favorable.

The plan to image both moons at once was years in the making and was made possible by the unique elliptical orbit of Mars Express, precise knowledge of the orbits of the planet, the moons and the spacecraft, as well as fortuitous viewing geometry, and perfect planning by the ESA and HRSC teams.

Exploration of Phobos: A Scientific Priority for Mars Express
In addition to producing high-resolution maps of the surface of Mars in color and in 3D, the exploration of Phobos is a scientific priority for the HRSC team. The potato-shaped, 27 × 22 × 18 km moon has already been photographed 127 times by the HRSC, improving our knowledge of the topography of the moon, and providing insight into its origins and development.

The moons of Mars still hold many mysteries. Phobos is made of dark material that does not reflect much light, and some scientists suspect it has a chemical composition similar to that of carbonaceous chondrite asteroids.

Phobos may also contain water ice, which could be an important resource for future Mars explorers. As missions like Mars Express continue to observe Phobos and Deimos, scientists hope to reveal more information about these unique satellites of Mars.