Jan 20

Surreal Lunar Orbit Footage From Doomed GRAIL Mission

By Caleb A. Scharf | January 11, 2013|

 

On December 17th 2012 two small spacecraft called Ebb and Flow punched into the lunar surface at over 3,700 miles an hour.

This ended the year long mission of NASA’s Gravity Recovery and Interior Laboratory (GRAIL). The twin spacecraft spent most of this time orbiting the Moon’s surface at a scarily low altitude of about 31 miles, sweeping in tandem above the dusty terrain never more than 140 miles apart from each other.

 

Gravity map of the Moon (Credit: NASA/JPL-Caltech/MIT/GSFC)

Microwave telemetry between the spacecraft, the Earth, and the application of basic geometry let GRAIL monitor the distance between Ebb and Flow to a precision of about a tenth of a micron – half the width of a human hair.

As with any planet or satellite the Moon’s gravitational field is not perfectly symmetrical. Variations in the density and height of material produce tiny variations in the gravitational acceleration felt by other objects. By sensing Ebb and Flow’s varying movement in orbit a detailed map of the lunar gravity field was constructed. With a knowledge of the topographic features on the surface this can be turned into the equivalent of a medical tomographic reconstruction of the lunar interior – and it’s lumps and bumps.

The data is amazing, but GRAIL had one last gift to give. In the days leading up to their crash on the lunar surface the spacecraft returned imagery from their ever lowering orbits.

This is the quite surreal and beautiful timelapse footage taken by Ebb as it skimmed across part of the northern terrain of the Moon’s far side at an altitude of only 6 miles on December 14th 2012. Enjoy.

 

 
 

Caleb A. ScharfAbout the Author: Caleb Scharf is the director of Columbia University’s multidisciplinary Astrobiology Center. He has worked in the fields of observational cosmology, X-ray astronomy, and more recently exoplanetary science. His latest book is ‘Gravity’s Engines: How Bubble-Blowing Black Holes Rule Galaxies, Stars, and Life in the Cosmos’, and he is working on ‘The Copernicus Complex’ (both from Scientific American / Farrar, Straus and Giroux.) Follow on Twitter @caleb_scharf.More »

Jan 19

Celestial Wonder Looks Uncannily Like a Manatee

by Clara Moskowitz, SPACE.com Assistant Managing Editor

A watery-looking nebula in deep space is being renamed after the sea creature it strongly resembles: a manatee.

The nebula is the leftovers from a star that died in a supernova explosion about 20,000 years ago. Before it died, the giant star puffed out its outer gaseous layers, which now swirl in green-and-blue clouds around the dead hulk of the star, which has collapsed into a black hole.

Known officially as W50, the celestial object is being dubbed the Manatee Nebula by the National Radio Astronomy Observatory (NRAO), during a ceremony today (Jan. 19) at the Florida Manatee Festival in Crystal River, Fla. The NRAO will also unveil a new photo of the nebula taken by the Very Large Array (VLA) radio telescope network in New Mexico.

 

“When the VLA’s giant W50 image reached the NRAO director’s office, Heidi Winter, the director’s executive assistant, saw the likeness to a manatee, the endangered marine mammals known as ‘sea cows’ that congregate in warm waters in the southeastern United States,” NRAO officials wrote in a statement.”

 

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Jan 19

The Galaxy Puzzle in the Constellation of Centaurus

Found This article at NASA’s site. Interesting but I really just like the Picture! 
 
 
 
Hubble Image: The Galaxy Puzzle in the Constellation of Centaurus 
 

Background stars burn from behind an almond-shaped blurry white galaxy and a diffuse speckled glob of stars

› Larger image

The Universe loves to fool our eyes, giving the impression that celestial objects are located at the same distance from Earth. A good example can be seen in this spectacular image produced by the NASA/ESA Hubble Space Telescope. The galaxies NGC 5011B and NGC 5011C are imaged against a starry background.

Located in the constellation of Centaurus, the nature of these galaxies has puzzled astronomers. NGC 5011B (on the right) is a spiral galaxy belonging to the Centaurus Cluster of galaxies lying 156 million light-years away from the Earth. Long considered part of the faraway cluster of galaxies as well, NGC 5011C (the bluish galaxy at the center of the image) is a peculiar object, with the faintness typical of a nearby dwarf galaxy, and the size of an early-type spiral.

Astronomers were curious about the appearance of NGC 5011C. If the two galaxies were at roughly the same distance from Earth, they would expect the pair to show signs of interactions between them. However, there was no visual sign of interaction between the two. How could this be possible?

To solve this problem, astronomers studied the velocity at which these galaxies are receding from the Milky Way and found that NGC 5011C is moving away far more slowly than its apparent neighbor, and its motion is more consistent with that of the nearby Centaurus A group at a distance of 13 million light-years. Thus, NGC 5011C, with only about ten million times the mass of the sun in its stars, must indeed be a nearby dwarf galaxy rather than a member of the distant Centaurus Cluster as was believed for many years.

Problem solved.

This image was taken with Hubble’s Advanced Camera for Surveys using visual and infrared filters.

 
 

ESA/Hubble & NASA