astronomy

independent.co.uk
Nasa announces major press conference on a 'discovery beyond our solar system'
Attending the press conference will be astronomers and planetary scientists from across the world.

Nasa is to host a major press conference on a “discovery beyond our solar system”.

The event will see the revelation of major information about exoplanets, or planets that orbit stars other than our sun, according to a release. It made no further mention of the details of what would be revealed.

Exoplanets are the major hope for life elsewhere in the universe, since many have been found that resemble our own Earth and could have the building blocks of life. More of them are being discovered all the time.

The event will take place on 22 February at 1pm New York time, it said. It will be streamed live on Nasa’s television station and on its website.

Attending the press conference will be astronomers and planetary scientists from across the world.

Nasa said that the public will be able to ask questions using the hashtag #AskNasa during the conference. The agency will also hold a Reddit AMA, or ask me anything, session straight after the briefing.

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Did Mars once have three moons?

“While the large Moon will be destined to be tidally destroyed and drawn to the surface through friction with Mars’ atmosphere, the other two moons could remain. Phobos and Deimos had a much larger sibling at some point in the past, but it may have lasted only for a few million years. After billions of years more, these two small moons remain. Perhaps in a few billion more, Phobos may be destroyed as well. If the new theory is right, a future scientist will only have Deimos and the basins on Mars to piece together this story from. It’s a stark reminder that in the Solar System and the Universe in general, the past is gone. All we have left to base its history on are the survivors.”

Compared to the other moons we know of in the Solar System, Mars’s two, Phobos and Deimos, are incredibly difficult to explain. They look like captured asteroids, being small, irregular, and exhibiting the right surface features. But captured asteroids form inclined or even retrograde orbits quite distant from their planet, while Phobos and Deimos live in circular, equatorial, close-in orbits to Mars. An alternative theory to the captured asteroid scenario is that the moons of Mars formed from a giant impact that kicked up a circumplanetary debris disk, similar to how Earth’s moon formed. But those scenarios never lead to merely two small moons; there’s always at least one large one. Thanks to a new simulation, all the pieces might finally be coming together.

Could Mars have had an inner, larger moon in the past that’s now decayed and collided back with the red planet? Get the story today!

Nebula Helix by Spitzer

This infrared image from NASA’s Spitzer Space Telescope shows the Helix Nebula. The nebula, located about 700 light-years away in the constellation Aquarius, belongs to a class of objects called planetary nebulae.

Image credit: NASA / Spitzer

Deep Magellanic Clouds Image Indicates Collisions : Did the two most famous satellite galaxies of our Milky Way Galaxy once collide? No one knows for sure, but a detailed inspection of deep images like that featured here give an indication that they have. Pictured, the Large Magellanic Cloud is on the bottom right. The surrounding field is monochrome color-inverted to highlight faint filaments, shown in gray. Perhaps surprisingly, the featured research-grade image was compiled with small telescopes to cover the large angular field nearly 40 degrees across. Much of the faint nebulosity is Galactic Cirrus clouds of thin dust in our own Galaxy, but a faint stream of stars does appear to be extending from the SMC toward the LMC. Also, stars surrounding the LMC appear asymmetrically distributed, indicating in simulations that they could well have been pulled off gravitationally in one or more collisions. Both the LMC and the SMC are visible to the unaided eye in southern skies. Future telescopic observations and computer simulations are sure to continue in a continuing effort to better understand the history of our Milky Way and its surroundings. via NASA

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flickr

la meduse by telemaq76
Via Flickr:
Ic443, la nebuleuse de la meduse 65 x 3 minutes exposures 23 darks, +flats and offsets

flickr

Cres StarTrails by Boris Štromar
Via Flickr:
Cres island, Croatia.

(ESA)  Supermassive and super-hungry

This NASA/ESA Hubble Space Telescope image shows the spiral galaxy NGC 4845, located over 65 million light-years away in the constellation of Virgo (The Virgin). The galaxy’s orientation clearly reveals the galaxy’s striking spiral structure: a flat and dust-mottled disc surrounding a bright galactic bulge.

NGC 4845’s glowing centre hosts a gigantic version of a black hole, known as a supermassive black hole. The presence of a black hole in a distant galaxy like NGC 4845 can be inferred from its effect on the galaxy’s innermost stars; these stars experience a strong gravitational pull from the black hole and whizz around the galaxy’s centre much faster than otherwise.