All posts by Tom

ALMA Sees Einstein Ring

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WOW!

About the image:
ALMA/Hubble composite image of the gravitationally lensed galaxy SDP.81. The bright orange central region of the ring (ALMA’s highest resolution observation ever) reveals the glowing dust in this distant galaxy. The surrounding lower-resolution portions of the ring trace the millimeter wavelength light emitted by carbon monoxide. The diffuse blue element at the center of the ring is from the intervening lensing galaxy, as seen with the Hubble Space Telescope. Credit: ALMA (NRAO/ESO/NAOJ); B. Saxton NRAO/AUI/NSF; NASA/ESA Hubble, T. Hunter (NRAO)

From the NRAO press release:

Astronomers have discovered that a distant galaxy — seen from Earth with the aid of a gravitational lens — appears like a cosmic ring, thanks to the highest resolution images ever taken with the Atacama Large Millimeter/submillimeter Array (ALMA).

Forged by the chance alignment of two distant galaxies, this striking ring-like structure is a rare and peculiar manifestation of gravitational lensing as predicted by Albert Einstein in his theory of general relativity.

Gravitational lensing occurs when a massive galaxy or cluster of galaxies bends the light emitted from a more distant galaxy, forming a highly magnified, though much distorted image. In this particular case, the galaxy known as SDP.81 (its formal name is HATLAS J090311.6+003906) and an intervening galaxy line up so perfectly that the light from the more distant one forms a nearly complete circle as seen from Earth.

Discovered by the Herschel Space Observatory, SDP.81 is an active star-forming galaxy nearly 12 billion light-years away, seen at a time when the Universe was only 15 percent of its current age. It is being lensed by a massive foreground galaxy that is a comparatively nearby 4 billion light-years away.

“Gravitational lensing is used in astronomy to study the very distant, very early Universe because it gives even our best telescopes an impressive boost in power,” said ALMA Deputy Program Scientist Catherine Vlahakis. “With the astounding level of detail in these new ALMA images, astronomers will now be able to reassemble the information contained in the distorted image we see as a ring and produce a reconstruction of the true image of the distant galaxy.”

Read the rest and see more images at the NRAO site.

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Martian Glaciers

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Most of us are familiar with the ice caps on Mars. Now research is pointing to glaciers on the Red Planet.

Researchers at the Niels Bohr Institute used radar observations and ice flow modeling to show the shape of the glaciers which occur in both hemispheres just below the surface.

It is not known if the glaciers are made of frozen water (H2O) or carbon dioxide (CO2) or even if it mud.

“We have looked at radar measurements spanning ten years back in time to see how thick the ice is and how it behaves. A glacier is after all a big chunk of ice and it flows and gets a form that tells us something about how soft it is. We then compared this with how glaciers on Earth behave and from that we have been able to make models for the ice flow,” explains Nanna Bjørnholt Karlsson, a postdoc at the Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen.

The researchers calculate the volume of the glaciers could be equivalent to the amount needed to cover the entire planet with 1.1 meters if ice!

This is a huge discovery if it turns out to be accurate.  Read the details at the Niels Bohr Institute.

The image depicts the glacial regions as blue dots. Image Credit: Mars Digital Image Model, NASA/Nanna Karlsson

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Iapetus

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The Cassini spacecraft took this image of Iapetus on 27 March from a distance of about a million km (621,000 miles). This is the second-closet approach to the moon in this mission phase. The closest was in 2011.

The image was taken with the narrow angle camera and gives a good view of the bright terrain in the north polar region.

Iapetus is 1,471 km / 914 miles in diameter. Iapetus is two-toned so the color shading isn’t shadow. The color is pretty close to natural color thanks to RGB filters, the image was brightened to bring out the darker features.

NASA’s description of the features:
The large basin at lower right, within the dark terrain, is named Turgis. The slightly smaller crater at the nine o’clock position is Falsaron. The two prominent craters just above image center are Roland and Turpin. At the limb around the three o’clock position is the darkened rim of the crater Naimon.

The image was produced by Tilmann Denk at Freie Universität in Berlin. Image Credit: NASA/JPL-Caltech/Space Science Institute

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There’s Still Time

Artist’s concept of NASA’s New Horizons spacecraft as it passes Pluto and Pluto’s largest moon, Charon, in July 2015. Image and caption Credit: NASA/JHU APL/SwRI/Steve Gribben

To help name soon to be discovered features on Pluto and its satellites. New Horizon’s is about to give us our first ever look at the Plutonion system as it speeds by at nearly 50,000 kmh / 31,000 mph making its close approach on 14 July.

The deadline has been extended until 24 April 2015.

“I’m impressed with the more than 40,000 thoughtful submissions,” said Mark Showalter, scientist New Horizons science team co-investigator, and SETI Institute in Mountain View, California, which is hosting the naming website. “Every day brings new lessons in the world’s history, literature and mythology. Participation has come from nearly every country on Earth, so this really is a worldwide campaign.”

The rules are pretty simple but need to be followed. Go to the nomination page at OurPluto.org to see the criteria and nominate a name.

Don’t miss out you probably won’t get another chance.

The image is an artist’s concept of NASA’s New Horizons spacecraft as it passes Pluto and Pluto’s largest moon, Charon, in July 2015.  Image and caption Credit: NASA/JHU APL/SwRI/Steve Gribben

 

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Venus in Radar

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Here is another radar image of Venus.   See another view at a previous post.

This image was made by transmitting a 13 cm wavelength signal (2.3 GHz) from Arecibo and picking up the return signal with the Green Bank Telescope.

Bright areas are rougher surfaces. The detail is good enough to see many features such as mountains, volcanic domes and a few craters.

Craters on Venus are relatively few at least compared to other planets. Given the density of the atmosphere most probably are destroyed in the atmosphere.

Image credit: NRAO.

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Where is Dawn?

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The Dawn spacecraft is still at Ceres. We haven’t seen any pictures from the spacecraft because as Dawn arrived its momentum carried it to a fairly (and planned) orbit. Currently it is decending into a lower orbit from which imaging will start again, by then the spacecraft will be about 13,500 km / 8,400 miles above the surface of Ceres.

At the moment and until about 09 April the orbital configuration is such that most of the time the ground below the spacecraft is dark and trying to image the surface really isn’t worth the effort.

Patience is the key, shortly Dawn will be be an orbit that will allow the surface to be seen again.

NASA’s Dawn page

About the image: 

This artist’s concept shows Dawn thrusting with its center ion engine high above the night side of Ceres, which displays only a narrow crescent below the spacecraft. The gentle but efficient thrust allows Dawn to change the shape of its orbit. It will complete this first phase of orbital maneuvering on April 23 when it achieves RC3 orbit. Image and caption: NASA/JPL

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LDSD Testing

LDSD being prepared for testing. Image Credit: NASA/JPL-Caltech
LDSD being prepared for testing. Image Credit: NASA/JPL-Caltech

It has been a while since we’ve heard much news of the Low-Density Supersonic Decelerator or LDSD.

The image above shows the LDSD flight-test vehicle in a NASA-JPL clean room. The LDSD is sitting on a spin table that was used to spin the 4.6 meter / 15 foot and 3,175 kg / 7,000 lb test vehicle to 30 rpm to check its balance. The LDSD is about to be flown to a naval facility in Kauai, Hawaii for further testing.

The June tests will involve lifting the LDSD by balloon to 36 km / 120,000 feet over the Pacific. At altitude the LDSD will be released and a booster rocket will ignite and carry it to 55 km / 180,000 feet and accelerating it to Mach 4 in the process. At the final altitude a series of automated tests of two new technologies will begin.

The supersonic inflatable aerodynamic decelerator also known at SAID-R, an inflatable doughnut will deploy. The result will be a larger vehicle with more drag that will slow the vehicle from about Mach 3.8 to Mach 2.5 when the worlds largest supersonic parachute ever will deploy. The parachute should enable a controlled landing in the Pacific Ocean 45 minutes later.

The new technologies tested should enable large payloads to be landed on Mars and other planets with atmoshpheres and at higher altitudes.

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A Five Minute Eclipse

This image shows the Dec. 20, 2012 total lunar eclipse, as seen from Sagamihara, Japan. Image Credit: NASA/MSFC/Alphonse Sterling

 

Europe was recently treated to a beautiful solar eclipse. Now there is a Total Lunar Eclipse coming to North America, South America, Middle Asia, including India, western China and mid-Asian Russia on 04 April.

Viewers in areas able to see the eclipse will have to look quick, the total eclipse will last only FIVE minutes! No fooling, this will be the shortest lunar eclipse this century. :mrgreen:

Fortunately people in eastern North America and western South America will get to see the early stages (partial umbral phase) of the eclipse in the western sky and people in Middle Asia, including India, western China and mid-Asian Russia will see the late stages low in the eastern sky just after sunset on 04 April.

Sorry Europe, Greenland, Iceland, Africa and the Middle East the eclipse will not be visible for you.

This is the third of a series of four eclipses in a row also known as a “tetrad”  The last two occurred in April and September 2014 and the last of the series will occur on 28 September 2015.

See a visibility map here.

The image at the top of the post shows the 20 December 2012 total lunar eclipse, as seen from Sagamihara, Japan.

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