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!

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.

cryptoking  asked:

This is more of an astronomical question than a physics question but which is brighter: Quasars or Supernovas?

Quasars, by far. A typical type II supernova has the luminosity of about 10^37 watts, while a quasar has a luminosity of about 10^39 watts. While these may be extremely bright, they are both outmatched when compared to gamma-ray bursts, the brightest things in the universe. Gamma-ray bursts have a luminosity of about 10^45 watts, about 19 orders of magnitude brighter than our own Sun.