Monicks: Unleashed

Tag: space

  • Hubble Pictures of the Week

    IC4634’s Glowing Waves

    This striking Hubble image of the planetary nebula IC 4634 reveals two shining, S-shaped ejections from a dying star. This star, awash in glowing material at the centre of the picture, bloated as it aged and launched its outer layers off into space. The star’s very hot, exposed core has since beamed intense ultraviolet radiation at these lost shells of gas, making them glow in rich colours.

    This process has been far from orderly or calm, however, as revealed by the distinct, separate waves of thrown-off gases. One is more distant and therefore was spewed first, followed by a more recently ejected tide of matter that formed the tighter S-shape. The result is remarkably symmetric on each side of the central star.

    The NASA/ESA Hubble Space Telescope’s Wide Field Planetary Camera 2 (WFPC2) captured this image of IC 4634, which is found more than about 7500 light-years away in the constellation of Ophiuchus (the Serpent Holder). IC 4634 and other objects like it are known as planetary nebulae due to their appearance through early telescopes as rounded, faintly luminous discs similar to the distant planets Uranus and Neptune. The picture was created from images through five different filters (F487N, F502N, F574M, F656N and F658N) that captured light emitted by different elements in the gaseous features. The total aggregate exposure time was 4000 seconds and the field of view is just 29 arcseconds across.

    A Clump of Galaxy Misfits

    That galaxies come in very different shapes and sizes is dramatically demonstrated by this striking Hubble image of the Hickson Compact Group 59. Named by astronomer Paul Hickson in 1982, this is the 59th such collection of galaxies in his catalogue of unusually close groups. What makes this image interesting is the variety on display. There are two large spiral galaxies, one face-on with smooth arms and delicate dust tendrils, and one highly inclined, as well as a strangely disorderly galaxy featuring clumps of blue young stars. We can also see many apparently smaller, probably more distant, galaxies visible in the background. Hickson groups display many peculiarities, often emitting in the radio and infrared and featuring active star-forming regions. In addition their galaxies frequently contain Active Galactic Nuclei powered by supermassive black holes, as well large quantities of dark matter.

    The NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys, using the Wide Field Channel, captured this image of HCG059 in 2007. The picture was created from images taken through blue, yellow and near-infrared filters (F435W, F606W and F814W). The total exposure times per filter were 57 minutes, 41 minutes and 35 minutes respectively. The field of view is about 3.4 arcminutes across.

    Credit: ESA/Hubble and NASA

    Posted via web from Monicks: Unleashed

  • Close Flybys of Two Moons in Less Than Two Days

    About a month and a half after its last double flyby, NASA’s Cassini spacecraft will be turning another double play this week, visiting the geyser moon Enceladus and the hazy moon Titan. The alignment of the moons means that Cassini can catch glimpses of these two contrasting worlds within less than 48 hours, with no maneuver in between.

    On the left, Saturn’s moon Enceladus is backlit by the sun, showing the fountain-like sources of the fine spray of material that towers over the south polar region. On the right, is a composite image of Titan. Image credit: NASA/JPL/SSI and NASA/JPL/University of Arizona.

    via spacefellowship.com

    Cassini will make its closest approach to Enceladus late at night on May 17 Pacific time, which is in the early hours of May 18 UTC. The spacecraft will pass within about 435 kilometers (270 miles) of the moon’s surface.

    The main scientific goal at Enceladus will be to watch the sun play peekaboo behind the water-rich plume emanating from the moon’s south polar region. Scientists using the ultraviolet imaging spectrograph will be able to use the flickering light to measure whether there is molecular nitrogen in the plume. Ammonia has already been detected in the plume and scientists know heat can decompose ammonia into nitrogen molecules. Determining the amount of molecular nitrogen in the plume will give scientists clues about thermal processing in the moon’s interior.

    The second of Cassini’s two flybys is an encounter with Titan. The closest approach will take place in the late evening May 19 Pacific time, which is in the early hours of May 20 UTC. The spacecraft will fly to within 1,400 kilometers (750 miles) of the surface.

    Cassini will primarily be doing radio science during this pass to detect the subtle variations in the gravitational tug on the spacecraft by Titan, which is 25 percent larger in volume than the planet Mercury. Analyzing the data will help scientists learn whether Titan has a liquid ocean under its surface and get a better picture of its internal structure. The composite infrared spectrometer will also get its southernmost pass for thermal data to fill out its temperature map of the smoggy moon.

    Cassini has made four previous double flybys and one more is planned in the years ahead.

    Posted via web from Monicks: Unleashed

  • Picture of the Day – Io Transit of Jupiter

    Io is roughly the size of Earth’s moon but 2,000 times farther away. In two of the images, Io appears to be skimming Jupiter’s cloud tops, but it’s actually 310, 000 miles (500,000 kilometers) away. Io zips around Jupiter in 1.8 days, whereas the moon circles Earth every 28 days.

    Io Transit of Jupiter. Credit: J. Spencer (Lowell Observatory) and NASA/ESA

    via spacefellowship.com

    The conspicuous black spot on Jupiter is Io’s shadow and is about the size of the moon itself (2,262 miles or 3,640 kilometers across). This shadow sails across the face of Jupiter at 38,000 mph (17 kilometers per second). The smallest details visible on Io and Jupiter measure 93 miles (150 kilometers) across, or about the size of Connecticut.

    Posted via web from Monicks: Unleashed