Auroral Corona over Norway  : Higher than the highest mountain lies the realm of the aurora. Auroras rarely reach below 60 kilometers, and can range up to 1000 kilometers. Aurora light results from energetic electrons and protons striking atoms and molecules in the Earth’s atmosphere. Somewhat uncommon, an auroral corona appears as a center point for a surrounding display and may occur when an aurora develops directly overhead, or when auroral rays are pointed nearly toward the observer. This picturesque but brief green and purple aurora exhibition occurred last month high above Kvalya, Troms, Norway. The Sessyfjorden fjord runs through the foreground, while numerous stars are visible far in the distance. via NASA

What’s the closest galaxy to us?

Apart from the Milky Way of course… the answer is surprising.

Most people would probably answer the Andromeda Galaxy, but this would be totally wrong.

A little over a decade ago my school co-conducted a survey with another to detail the night sky around us.

Among many of the discoveries made in this survey was that there was something strange going on about 25,000 lightyears from Earth. The stars in that area were unusually dense.

In addition, the collection of stars was elliptical-shaped.

The incredible part?

It’s inside the Milky Way.

Canis Major Dwarf Galaxy, a small galaxy of a billion stars, is now thought to be the closest (non-Milky Way) galaxy to Earth at a mere 25,000 lightyears away from Earth.

It was likely an independent galaxy until our much larger one ate it. It’s since  been leaving a trail of stars as it orbits around the middle of the Milky Way.

This means, like the Galapagos, you’d better go there soon if you want to see what it’s like. In a few billion years its stars may all have been stolen by the gravity of the Milky Way.

(Image credit: VncntM)

NASA Astronomy Picture of the Day 2015 March 4

Pillars and Jets in the Pelican Nebula

What dark structures arise from the Pelican Nebula? Visible as a bird-shaped nebula toward the constellation of a bird (Cygnus, the Swan), the Pelican Nebula is a place dotted with newly formed stars but fouled with dark dust. These smoke-sized dust grains formed in the cool atmospheres of young stars and were dispersed by stellar winds and explosions. Impressive Herbig-Haro jets are seen emitted by a star on the right that is helping to destroy the light year-long dust pillar that contains it. The featured image was scientifically-colored to emphasize light emitted by small amounts of ionized nitrogen, oxygen, and sulfur in the nebula made predominantly of hydrogen and helium. The Pelican Nebula (IC 5067 and IC 5070) is about 2,000 light-years away and can be found with a small telescope to the northeast of the bright star Deneb.

M106: A Spiral Galaxy with a Strange Center  : What’s happening at the center of spiral galaxy M106? A swirling disk of stars and gas, M106’s appearance is dominated by blue spiral arms and red dust lanes near the nucleus, as shown in the featured image. The core of M106 glows brightly in radio waves and X-rays where twin jets have been found running the length of the galaxy. An unusual central glow makes M106 one of the closest examples of the Seyfert class of galaxies, where vast amounts of glowing gas are thought to be falling into a central massive black hole. M106, also designated NGC 4258, is a relatively close 23.5 million light years away, spans 60 thousand light years across, and can be seen with a small telescope towards the constellation of the Hunting Dogs (Canes Venatici). via NASA

husseyshy asked:

Is there any chance of earth getting destroyed by asteroid soon or later ?

Big time! Every day roughly a hundred tons of meteoroids enter Earth’s atmosphere. Most of these things don’t present a danger but every now and then a huge one, like the one that hit Earth around Chelyabinsk, Russia can cause incredible damage.

Obviously all it takes is one impact from one large object and the entire surface of the Earth could be liquified into roiling oceans of lava. Some of the fragments of Earth thrown into the air and space will have been superheated into fragments of glass which would then rain down all over the Earth.

Nothing like this has happened for a long time but remember… it only takes one…

Which is why everyone should support the Planetary Society’s effort to create a grant for astronomers that will fund a search for dangerous Near Earth Objects (NEOs). If we’re successful then everyone on Earth will benefit from this early-warning system. If we know there’s something out there coming towards us soon enough, we can do something about it! :)

If you’re interested in helping us or finding out more, click here.

NASA-Funded Study Finds Two Solar Wind Jets in the Heliosphere













NASA logo / NASA - IBEX Mission patch.

March 3, 2015

As the sun skims through the galaxy, it emits charged particles in a stream of plasma called the solar wind. The solar wind, in turn, creates a bubble known called the heliosphere that extends far beyond the planets of the solar system. For decades, scientists have visualized the heliosphere as shaped like a comet, with a very long tail extending some 464 billion miles, which is thousands of times as far as the distance from Earth to the sun.


Image above: A new simulation of the heliosphere – the magnetic bubble surrounding the sun – shows it to have two relatively short jets streaming away from the nose. Image Credit: M. Opher/Reproduced by permission of the AAS.

New NASA-funded research now suggests that the heliosphere is actually dominated by two giant jets of material shooting backwards over the north and south poles of the sun, which are confined by the interaction of the sun’s magnetic field with the interstellar magnetic field. These curve around in two—relatively short – tails toward the back. The end result is a heliosphere without that long tail; a heliosphere that looks a lot more like a crescent moon than a comet. What’s more, the two jets are similar to other astrophysical jets seen in space, so studying them locally could open doors to understanding such jets throughout the universe. The research is described in a paper in Astrophysical Journal Letters, which appeared online on Feb. 19, 2015.

"Everyone’s assumption has been that the shape of the heliosphere was molded by the flow of interstellar material passing around it," said Merav Opher, an astronomer at Boston University, who is lead author on the paper. "Scientists thought the solar wind flowing down the tail could easily pull the magnetic fields in the heliosphere along as it flowed by, creating this long tail. But it turns out the magnetic fields are strong enough to resist that pull – so instead they squeeze the solar wind and create these two jets."

Opher and her colleagues found the jets and determined the new shape when they adjusted simulations of the heliosphere based on observations collected from NASA’s Voyager 1 spacecraft, which recently moved outside of the heliosphere into interstellar space. As the first man-made object outside of our solar system, Voyager provided our only glimpse so far of the interstellar medium and it provided one giant surprise: The magnetic fields out there were aligned pretty much the same as the ones in here, though it had long been expected they would be oriented in a different direction.


Images above: Scientists think the magnetic bubble around our sun may look more like the shortened one as seen in this image of the star BZ Cam (left), as opposed to the long one as seen around the star Mira (right). Image Credit: NASA/Casalegno/GALEX.

Opher — along with space scientist Jim Drake at the University of Maryland in College Park who is a co-author on the paper – had previously created models based on computer code developed by space physicists at the University of Michigan of the heliosphere. Their previous work focused on the nose of the heliosphere, trying to understand the physics there as we hurtle through space. To see if they could replicate the unexpected Voyager results, the team created a higher resolution simulation.

The new simulation described a heliosphere unlike one considered before.

“The Voyagers had a flashlight in the kitchen, and nobody was looking in the attic,” she remarks. “We noticed, while studying the draping of the galaxy’s magnetic field around the nose, that the heliosphere was much shorter than we anticipated.”

Instead of being dominated solely by the flow of the interstellar material to create a long tail, the shape of the heliosphere is also affected by the solar wind jets emanating from the sun, said Drake.

"If there were no interstellar flow, then the magnetic fields around the sun would shape the solar wind into two jets pointing straight north and south," said Drake. "The magnetic fields contract around these jets, shooting the solar wind out like squishing a tube of toothpaste."

In the presence of the interstellar flow, these jets are bowed backwards, creating a crescent shape, as seen from the side of the sun. The jets erode in the presence of the strong interstellar flow, leading to two attenuated, short tails. This leads to a much shorter heliosphere of only about 250 times the distance between Earth and the sun, or about 23 billion miles.


Image above: The yellow shape is the heliopause, the boundary between the heliosphere and the local interstellar medium. The sun sits at the center of this bubble, but is too small to be seen here. The gray lines are the solar magnetic field lines and the red lines are the interstellar magnetic field. Image Credit: M. Opher.

"Not only is the heliosphere’s shape different from what people thought," said Drake. "But the mechanism for these jets is the same as in many astrophysical systems. Astrophysical jets elsewhere produce energetic particles, but they are remote and hard to diagnose. Our jets are nearby so we might be able to figure out how they produce the energetic particles measured in the heliosphere."

To support their heliosphere model, the scientists turned to additional observations of the tail. Both NASA’s Cassini and Interstellar Boundary Explorer, or IBEX, have gathered information about the tail end of the heliosphere by looking at what’s called energetic neutral atoms, or ENAs. ENAs are created by energetic particle collisions in space and conveniently travel in straight lines, unlike many other particles in space. Observing ENAs traveling in from a certain area, therefore, can be used to map that region.

"Cassini data showed a similar amount of ENAs from the tail and the nose," said Opher.  "Suggesting that the size of both sides was similar, which means a short tail."

An IBEX paper from 2013 also described as a two-lobed shape down the tail. Opher and Drake suggest that the lobes observed might actually have been the two jets with interstellar, non-heliospheric material in between. The paper on the IBEX results, however, interpreted the heliosphere as having a long tail.

With such previous results, Opher expects the new model to be controversial. “This is going to be heavily, heavily debated,” she said, pointing out that many scientists work from the traditional comet-shaped model of the heliosphere. But, said Opher, the out-of-the-box results coming from spacecraft observations demand a similarly unconventional explanation.

In the meantime, these newly postulated jets look like baby versions of the super-powered jets that exist around exotic objects like black holes and pulsars. They are also seen around proto-stars just being born.  Being able to study these jets in our own backyard provides a homegrown laboratory in which to study a structure that is seen everywhere in the universe.

“If we’re right about all of this, it gives us a local test bed for exploring some very important physics,” said Drake.

Related Links:

More on IBEX and the heliotail: http://www.nasa.gov/content/nasa-s-ibex-provides-first-view-of-the-solar-system-s-tail/

New View of the Solar System: Astrophysical Jets Driven by the Sun: https://cmns.umd.edu/news-events/features/2804

New Vision of the Final Frontier: http://www.bu.edu/research/articles/new-vision-of-the-final-frontier/

Images (mentioned), Text, Credits: NASA’s Goddard Space Flight Center/Karen C. Fox.

Greetings, Orbiter.ch
Full article

Hubble Sees an Ancient Globular Cluster : This image captures the stunning NGC 6535, a globular cluster 22,000 light-years away in the constellation of Serpens that measures one light-year across.

Globular clusters are tightly bound groups of stars which orbit galaxies. The large mass in the rich stellar centre of the globular cluster pulls the stars inward to form a ball of stars. The word globulus, from which these clusters take their name, is Latin for small sphere.

Globular clusters are generally very ancient objects formed around the same time as their host galaxy. To date, no new star formation has been observed within a globular cluster, which explains the abundance of aging yellow stars in this image, most of them containing very few heavy elements.

NGC 6535 was first discovered in 1852 by English astronomer John Russell Hind. The cluster would have appeared to Hind as a small, faint smudge through his telescope. Now, over 160 years later, instruments like the Advanced Camera for Surveys Hubble Space Telescope allow us to marvel at the cluster and its contents in greater detail.

European Space Agency
Credit: ESA/Hubble & NASA, Acknowledgement: Gilles Chapdelaine

10

    The AD-1 (Ames-Dryden One) is arguably NASA’s strangest looking aircraft. She was a collaborative effort between the Ames and Dryden (now Armstrong) research centers to explore a new concept variable geometry wing. Changing the geometry of a wing in flight makes an aircraft operate more efficiently at a wider range of speeds. Variable geometry wings have been successfully deployed on many aircraft like the Grumman F-14 Tomcat in a variable-sweep, or swing wing configuration. The swing wing design requires complicated, heavy mechanisms with many moving parts which decreases reliability and increases maintenance cost and time. Instead of a swing wing, the AD-1 uses an oblique wing design, rotating its entire wing with a light, simple mechanism.

     She was designed by the Rutan Aircraft Company in Mojave, California and built by The Ames Industrial Company in Bohemia, New York, making the first and only manned oblique wing aircraft. The AD-1 first took to the air over NASA Dryden Flight Research Center on December 21, 1979, piloted by Thomas C. McMurtry. NASA pilots gradually increased the rotation angle of the wing up to 60 degrees over the course of the program. This exposed strange flying characteristics which coupled roll and pitch because of its asymmetric design. This could easily be solved in future aircraft using digital stability augmentation systems. McMurty flew the last flight of the program on August 7, 1982 at the Experimental Aircraft Association Annual Convention in Oshkosh, Wisconsin. Now, she hangs in Hiller Aviation Museum in San Carlos, California.

Pillars and Jets in the Pelican Nebula

(via APOD; Image Credit & Copyright: Larry Van Vleet (LVVASTRO) )

What dark structures arise from the Pelican Nebula? Visible as a bird-shaped nebula toward the constellation of a bird (Cygnus, the Swan), the Pelican Nebula is a place dotted with newly formed stars but fouled with dark dust. These smoke-sized dust grains formed in the cool atmospheres of young stars and were dispersed by stellar winds and explosions. Impressive Herbig-Haro jets are seen emitted by a star on the right that is helping to destroy the light year-long dust pillar that contains it. The featured image was scientifically-colored to emphasize light emitted by small amounts of ionized nitrogen, oxygen, and sulfur in the nebula made predominantly of hydrogen and helium. The Pelican Nebula (IC 5067 and IC 5070) is about 2,000 light-years away and can be found with a small telescope to the northeast of the bright star Deneb.