The NASA/ESA Hubble Space Telescope has revisited one of its most iconic and popular images: the Eagle Nebula’s Pillars of Creation. This time Hubble has not just one image for us, but two: as well as the new visible-light image the telescope used infrared light to produce a second breathtaking picture of the region. Between them these images show the pillars in more detail than ever before. In this Hubblecast we explore the different ways in which Hubble, and other telescopes, have captured this iconic object.
Saturday, June 13, 2015
Google Street View now takes you under the sea
You can now swim with the whales without getting wet, thanks to Google's new Street View tours of the ocean's depths.
As described in a new blog posted Thursday, Google has posted new Street View imagery of more than 40 underwater spots around the world, including the American Samoa in the South Pacific Ocean and Chagos Islands in the Indian Ocean, as well as deep sea dives in Bali, the Bahamas and the Great Barrier Reef. The views reveal the beauty of whales, fish and other creatures under the sea as well as corral reefs, shipwrecks and other areas to explore.
The new images are a change of pace for Google, which usually keeps its Street View tours above the water. But the virtual tours are more than just a guide to marvel at the wonders under the sea. Posted in time for World Oceans Day on June 8, the images are also a way to focus on the harm being done to our oceans and the attempts to preserve the undersea world.
"Home to the majority of life on Earth, the ocean acts as its life support system, controlling everything from our weather and rainfall to the oxygen we breathe," Google said in its blog. "Yet despite the ocean's vital importance, the ocean is changing at a rapid rate due to climate change, pollution, and overfishing, making it one of the most serious environmental issues we face today."
To foster a greater awareness of the sea, Google created the images in partnership with the XL Catlin Seaview Survey, NOAA's Office of National Marine Sanctuaries and the Chagos Conservation Trust, all of which are dedicated to studying the oceans and educating people about the hazards they face.
"Mapping the ocean is key to preserving it, Google said. "Each image in Google Maps is a GPS-located digital record of these underwater and coastal environments, which can be used as a baseline to monitor change over time."
As one example cited, the Great Barrier Reef faces such threats as an increase in storms and rising water temperatures, causing the reefs to bleach white. The imagery collected and displayed by Google can track the ongoing color changes to the reefs.
As with all Street View images, you can zoom in or out and move the cursor in any direction to get a panoramic view of your subject. Some of the most fascinating images give us up-close views of the magnificent creatures that call the ocean their home. One image shows us a sea turtle swimming near the Solomon Islands. Another brings us to a humpback whale in the Cook Islands. A third image offers a peek at great white sharks in Australia. And a fourth shows us a huge sunfish (Mola mola) swimming in Bali.
Ultimately, Google plans to publish more Street View images of the ocean's depths as a way for people to explore it and understand the changes that the undersea world is undergoing and will undergo over the coming years.
The new underwater panoramic views not only reveal the beauty beneath the sea but also call attention to the damage being done to Earth's oceans by climate change, pollution and overfishing.
Friday, June 12, 2015
Black holes are often thought to be a fairly destructive force in the universe -- but there's a lot more to them than meets the eye. Most galaxies, it seems, can't exist without them; and they also may play a role in the formation of stars and galaxies.
A new discovery by a team of researchers using the National Science Foundation's Very Large Array in New Mexico deals very much with the destructive side. Peering 1.1 billion light-years from Earth at an otherwise "boring" area of space called the Teacup Galaxy (J1430+1339) the team has discovered violent storm activity at its core -- demonstrating just how catastrophic black holes can be.
"It appears that a supermassive black hole is explosively heating and blasting around the gas in this galaxy and, as a result, is transforming it from an actively star-forming galaxy into one devoid of gas that can no longer form stars," said study lead author Chris Harrison from The Centre for Extragalactic Astronomy at Durham University in the UK.
The two most common types of galaxy that we have observed in the universe are spiral and elliptical. Spiral galaxies -- like our own Milky Way, and the nearby Andromeda -- make up around 60 percent of the galaxies we have seen, and are rich in gas and alive with activity and star formation.Ellipticals, on the other hand -- making up 10-15 percent of all galaxies -- have very little gas and very little star formation, ageing with a minimum of new growth.
These elliptical galaxies, researchers theorise, started out their lives as active star-forming galaxies -- after all, the stars had to come from somewhere -- yet at some point, star formation slowed almost to a halt. This, recent research suggests, could be due to the black holes in their hearts.
And perhaps those black holes are storming, if the Teacup Galaxy is any indication. It has been identified as having a supermassive black hole at its core actively consuming material and while it already has the appearance of an elliptical galaxy, observations have found gas surrounding the galaxy, indicating that it is only in the process of transitioning into an elliptical galaxy.
"For many years, we've seen direct evidence of this happening in galaxies that are extremely bright when viewed through radio telescopes. These, rare, radio-bright galaxies harbor powerful jets, launched at the black hole, that plow into the surrounding gas," Harrison said. "However, to understand how all of galaxies in our Universe formed, we needed to know if these same processes occur in less extreme galaxies that better represent the majority."
“Potentially Hazardous Asteroid (1566) Icarus rare encounter” – 16 June 2015, 21:30UT
Images can be shared freely, crediting the Virtual Telescope Project
(1566) Icarus rare close encounter
live observing session
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Our new neighbours: Rare dwarf galaxies found orbiting the Milky Way
The Milky Way galaxy now officially has new neighbours. Nine dwarf satellites, including three tiny galaxies, in orbit around our home galaxy were spotted by astronomers at the University of Cambridge in the skies of the southern hemisphere. The galaxies were found near the Large and Small Magellanic Cloud -- the two largest and most well-known dwarf galaxies in orbit around the Milky Way.
"The discovery of so many satellites in such a small area of the sky was completely unexpected," said lead author Dr Sergey Koposov of Cambridge's Institute of Astronomy. "I could not believe my eyes."
Discovered in newly released imaging data from the Dark Energy Survey, the find consists of three confirmed dwarf galaxies and six objects that could be either be dwarf galaxies or globular clusters -- the difference being that the stars in globular clusters are not held together with dark matter.
Dwarf galaxies are the smallest of all the observed galactic structures, sometimes as small as just 5,000 stars -- compared to the Milky Way's estimated 200 to 400 billion stars. It is also estimated that they contain up to 99 percent dark matter, and just one percent observable matter, which makes them perfect for testing dark matter models.
"Dwarf satellites are the final frontier for testing our theories of dark matter," said study co-author Dr Vasily Belokurov of the Institute of Astronomy. "We need to find them to determine whether our cosmological picture makes sense. Finding such a large group of satellites near the Magellanic Clouds was surprising, though, as earlier surveys of the southern sky found very little, so we were not expecting to stumble on such treasure."
The closest of the three dwarf galaxies, 97,000 light-years away and located in the constellation Reticulum, is in the process of being pulled apart by the Milky Way's enormous tidal forces. The farthest and brightest, 1.2 million light-years away in the constellation Eridanus, is right on the edge of the Milky Way and is on the verge of being pulled in.
"These results are very puzzling," said co-author Wyn Evans of the Institute of Astronomy. "Perhaps they were once satellites that orbited the Magellanic Clouds and have been thrown out by the interaction of the Small and Large Magellanic Cloud. Perhaps they were once part of a gigantic group of galaxies that -- along with the Magellanic Clouds -- are falling into our Milky Way galaxy."
Current estimates put the possible number of dwarf galaxies in orbit around the Milky Way in the hundreds, but they are very hard to find, since they are so faint. So far, fewer than 30 dwarf satellite galaxies have been identified.
The full study was published in The Astrophysical Journal. "Beasts of the Southern Wild. Discovery of a large number of Ultra Faint satellites in the vicinity of the Magellanic Clouds" can be found online.
Hubble eyes activity on Saturn
Saturn's north pole is an interesting place. This series of Hubble images show auroral lights shifting at the pole. The ultraviolet images were taken using the space telescope's Advanced Camera for Surveys. "The cause of the changing patterns in Saturn's aurorae is an ongoing mystery in planetary science," NASA notes.
Monkey Head Nebula
Hubble celebrated its 24th anniversary with an infrared-light image of a portion of the Monkey Head Nebula. Glowing gas and dust are visible in this image. It's an active area of star birth located 6,400 light-years away.
Spiral galaxy shimmers
This comely spiral galaxy NGC 1566 is about 40 million light-years away. The galaxy is part of the Seyfert class of galaxies. "The centers of such galaxies are very active and luminous, emitting strong bursts of radiation and potentially harboring supermassive black holes that are many millions of times the mass of the sun," says NASA.
Hubble peeks at Jupiter
NASA's Hubble Space Telescope doesn't just look at far-flung galaxies and nebulae. It sometimes takes a gander at planets located a little closer to home. This close-up look at Jupiter was taken in spring 2014 when Hubble was watching for changes in the planet's Great Red Spot storm.
Hubble spies a bubble
This bubbly nebula can be found in a little-known constellation called Camelopardalis (The Giraffe). Known asNGC 1501, the nebula displays all sorts of lumps and bumps around its shape. The light at the center comes from a star. The nebula's nickname is the Oyster Nebula due to it appearing to have a "pearl" inside a shell.
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