The International Space Station. Credit: NASA

Sunday, April 27, 2014

THE MASSIVE EL GORDO GALAXY CLUSTER

FROM:  NASA 

NASA's Hubble Space Telescope has weighed the largest known galaxy cluster in the distant universe, catalogued as ACT-CL J0102-4915, and found it definitely lives up to its nickname -- El Gordo (Spanish for "the fat one"). By measuring how much the cluster's gravity warps images of galaxies in the distant background, a team of astronomers has calculated the cluster's mass to be as much as 3 million billion times the mass of our sun. Hubble data show the galaxy cluster, which is 9.7 billion light-years away from Earth, is roughly 43 percent more massive than earlier estimates. The team used Hubble to measure how strongly the mass of the cluster warped space. Hubble's high resolution allowed measurements of so-called "weak lensing," where the cluster's immense gravity subtly distorts space like a funhouse mirror and warps images of background galaxies. The greater the warping, the more mass is locked up in the cluster.  Credit-NASA-ESA.

Sunday, April 20, 2014

IN THE CONSTELLATION LIBRA


FROM:  NASA 

This new Hubble image is centered on NGC 5793, a spiral galaxy over 150 million light-years away in the constellation of Libra. This galaxy has two particularly striking features: a beautiful dust lane and an intensely bright center — much brighter than that of our own galaxy, or indeed those of most spiral galaxies we observe. NGC 5793 is a Seyfert galaxy. These galaxies have incredibly luminous centers that are thought to be caused by hungry supermassive black holes — black holes that can be billions of times the size of the sun — that pull in and devour gas and dust from their surroundings. This galaxy is of great interest to astronomers for many reasons. For one, it appears to house objects known as masers. Whereas lasers emit visible light, masers emit microwave radiation. The term "masers" comes from the acronym Microwave Amplification by Stimulated Emission of Radiation. Maser emission is caused by particles that absorb energy from their surroundings and then re-emit this in the microwave part of the spectrum. Naturally occurring masers, like those observed in NGC 5793, can tell us a lot about their environment; we see these kinds of masers in areas where stars are forming. In NGC 5793 there are also intense mega-masers, which are thousands of times more luminous than the sun.   Credit:  NASA, ESA, and E. Perlman (Florida Institute of Technology)

Sunday, April 13, 2014

THE BIG SPOT ON JUPITER

FROM:  NASA 

At about 89,000 miles in diameter, Jupiter could swallow 1,000 Earths. It is the largest planet in the solar system and perhaps the most majestic. Vibrant bands of clouds carried by winds that can exceed 400 mph continuously circle the planet's atmosphere. Such winds sustain spinning anticyclones like the Great Red Spot -- a raging storm three and a half times the size of Earth located in Jupiter’s southern hemisphere. In January and February 1979, NASA's Voyager 1 spacecraft zoomed toward Jupiter, capturing hundreds of images during its approach, including this close-up of swirling clouds around Jupiter's Great Red Spot. This image was assembled from three black and white negatives. The observations revealed many unique features of the planet that are still being explored to this day. > View more images and watch a time-lapse of Jupiter assembled from images taken by the spacecraft Credit: NASA's Goddard Space Flight Center. Images courtesy of NASA-JPL