Category: Astronomy

Many of the stars in the Universe are located in binary or multiple star system, where several stars orbit a common centre of gravity. But astronomers have discovered an extreme binary system, where two of the largest possible stars orbit one another.

The discovery was made using NASA’s Far Ultraviolet Spectroscopic Explorer (FUSE) satellite, as well as ground-based observatories. FUSE turned up a system called LS54-425 in the Large Magellanic Cloud, a satellite galaxy of the Milky Way. This system contains two stars: one with 37 times the mass of the Sun, and the other is 62 solar masses.

Although they’re extremely massive, these two type-O stars only orbit one another at 1/6th the distance between the Earth and the Sun, completing an orbit within 2.25 days. Both stars are generating massive solar winds, which collide, giving off X-rays and ultraviolet radiation. And this is how FUSE was able to spot them.

The more massive star is shedding material about 400 times as fast as our Sun, and the smaller star gives off about 40 times as much material. As they age and grow, the two stars will transfer a tremendous amount of material to each other, and eventually they will merge, creating a single star of 100 times the mass of the Sun.

And then, within just a few million years, this super star will detonate as a very energetic supernova.

Original Source: NASA News Release

Astronomers know of several kinds of explosions in space. Supernovae occur when massive stars detonate or become black holes. Gamma ray bursts occur for certain kinds of supernovae, or the collision between compact objects, like neutron stars. And novae happen when stellar material piles up on the surface of a star or white dwarf, and then detonates. But now it looks like a new class of explosions have been identified: a red luminous nova.

The explosive event was discovered in a nearby galaxy in the Virgo cluster called Messier 85. Astronomers watched a star flare up, not as bright as a supernova, but much brighter than a nova. Instead of a quick flash, it brightened up much more slowly, with a distinctive red colour.

Astronomers speculate that the explosion occurred when two ordinary stars in a binary system finally came together, undergoing a process called “common envelope evolution”.

The cooling afterglow of the explosion was too dim to see in Hubble, but it was still bright enough in the infrared spectrum to see with the Spitzer Space Telescope. There’s little doubt that it’s a new class of object, and now astronomers will be fine tuning their searches to turn up more objects like this.

Original Source: Caltech News Release

When a gamma ray burst detonates, it releases more energy in just a few minutes than our Sun does in its entire lifetime. For a brief time, a gamma ray burst outshines its entire host galaxy. And now NASA’s Swift satellite has found evidence that some bursts can remain active for minutes, or even hours.

Gamma ray bursts are now believed to be a special kind of supernova, where the core of a massive star collapses into a black hole or neutron star. Inrushing gas forms a disk around the central core, and magnetic fields channel material into twin jets emanating from the black hole at nearly light speed.

Early observations by NASA’s Swift satellite found that gamma ray bursts are often followed minutes or hours later by short-lived X-ray flares. These flares suggested that the object that created the gamma ray burst is still active, after that initial flash. Instead of consuming all the material in a single burst of energy, there seem to be ongoing waves of material falling into the black hole. With each wave of consumption, the black hole gives off a torrent of X-ray radiation until everything is gone.

Original Source: NASA News Release

Jets of material have been seen blasting out of quasars, young stars, black holes and other massive objects. But now astronomers have discovered that even a lowly brown dwarf can have jets of outflowing material.

The discovery was made using the European Southern Observatory’s Very Large Telescope, which observed the brown dwarf 2MASS1207-3932. It was already a very interesting object because it has a 5 Jupiter mass planetary companion, and it’s surrounded by a planetary disc, like a young star. And like many young stars, it’s spewing jets of material from its poles.

The brown dwarf only has about 24 times the mass of Jupiter, so it’s not large enough to ignite solar fusion. But even so, it has these twin jets of outflow, stretching out a billion kilometres into space.

With an object this small having jets, astronomers think that young giant planets could also have outflows.

Original Source: ESO News Release

When astronomers look into the night sky, they see back into time. The light from the most distant galaxies has taken billions of years to reach us. Astronomers can measure that these galaxies are hurtling away from us, as part of the Universe’s expansion after the Big Bang. The more distant a galaxy is, the more quickly it’s moving away from us.

We know that the Universe started from a single point billions of years ago, we know that it’s expanding, and thanks to the mysterious dark energy, we know that this expansion is accelerating. In billions of years, distant galaxies will be speeding away from the Milky Way so quickly that they will recede from us faster than the speed of light. Their light will dim and fade away, and disappear from our view of the cosmos, forever inaccessible and unknowable.

And three trillion years from now, all the galaxies will have passed over the horizon, and faded from view. Future cosmologists will know of only one galaxy: ours. The Universe will appear static and unchanging, slowly cooling away. And this view will be the same from all points of view in the Universe. Physicists in every galaxy will only know of their own home, and nothing else.

This bleak view of our lonely future is all thanks to some new calculations from Lawrence Krauss from Case Western Reserve University and Robert J. Scherrer from Vanderbilt University. Their new article, called the “The Return of the Static Universe and the End of Cosmology,” was recently award a prize by the Gravity Research Foundation, and will be published in the October issue of the Journal of Relativity and Gravitation.

“While physicists of the future will be able to infer that their island universe has not been eternal, it is unlikely they will be able to infer that the beginning involved a Big Bang,” report the researchers.

Another powerful tool that astronomers use to know the Universe is the cosmic microwave background radiation; the afterglow from the Big Bang. The light from these early moments of our Universe has already been red shifted to longer and longer wavelengths with the expansion of the Universe. What used to be visible light is now microwave radiation, and will move through the radio spectrum. Eventually the wavelengths will be so large that astronomers will have no way to detect it.

Researchers also measure the quantities of hydrogen, helium and deuterium across the Universe. Their quantities match predictions for what should have occurred in the Big Bang. For a period, the entire Universe was like a giant star, converting primordial gas into heavier elements. Rapid expansion ended this period, and future elements were formed only within stars. Although the quantities of these elements match predictions today, our future galaxy will have dispersed them and combined them so thoroughly that they’ll be indiscernible as the helium produced in stars will dominate.

“Eventually, the universe will appear static,” said Krauss. “All evidence of modern cosmology will have disappeared.”

We can only hope that research done by cosmologists today is preserved, so future physicists can know that the true nature of the Universe, and not the static place they see around them.

The Universe Today spaceport is happy to host the third Carnival of Space. This is a roundup of cool articles about space and astronomy from bloggers and writers from across the Internet. By reading through this list of articles, we hope you’ll find some new articles to enjoy, and some new blogs to follow.

Now, let’s see who’s arrived at the spaceport…

The Space Cynics are celebrating their 1 year anniversary with a refresher course on their view of alt.space, the roadmap for space development, and why they’re so cynical.

The EarthSky Blog has this article by David S.F. Portree called Saving Spaceflight. He considers the thorny question of whether the emphasis in the space program should be on human exploration or robot probes.

When he’s not herding cats on his blog, Dynamics of Cats, Steinn Sigurdsson is writing about the launch of Corot and its first planetary discovery.

Amanda Bauer (aka the astropixie) recently spent an evening commanding the gigantic Gemini south telescope. But even that responsibility couldn’t keep her from gazing into the heavens from that Chilean peak into some of the clearest skies on Earth.

On the Physics Forums, there’s an interesting article called Andromeda Looming Large, about how the mighty Andromeda galaxy is larger than previously thought.

Chuck Magee from the Lounge of the Lab Lemming explains how Uranium Thorium star dating works. This is how they know a star can be 13.2 billion years old.

The Space Writer’s going down into an invisible ring of dark matter. Care to join?

Alan Boyle reports on his MSNBC Cosmic Log how a venture that uses outer space to generate random numbers is finally in the midst of a soft launch.

L. Riofrio from A Babe in the Universe was working on a story of how Hubble proved that the Universe was expanding and Einstein’s cosmological constant was a blunder. As the story was posted, a huge fire broke out threatening the observatory.

Emily Lakdawalla from The Planetary Society Weblog reports on how scientists have figured out that Asteroid Itokawa shakes and vibrates every time it’s hit by little rocks, and those vibrations cause Itokawa’s gravels and boulders to migrate around the asteroid’s surface and sort by size.

The Bad Astronomer Phil Plait highlights the amazing new discovery about a ring of dark matter surrounding a galaxy cluster collision, with a picture that will surely end up as your computer desktop.

Then let’s peek in with James Watt and his article about one of the many obstacles to space exploration: air.

My Astronomy Cast co-host, Dr. Pamela Gay sees a new day rising on other worlds.

And last, but not least, here’s my story on Universe Today about how you can enjoy a few extra nanoseconds of subjective time during your descent into a black hole.

Since I just can’t get enough of the Carnival of Space, I’ll be hosting it again next week. Here are your instructions to get involved for next time. I’ll see you next week.