Nice pic. of the Discovery on approach to the ISS, taken from earth.

This is an image of the Space Shuttle Discovery taken from the ground, no easy feat in itself. But it wasn’t taken by an observatory or a massive scientific instrument. Rob Bullen snapped this image from the UK using an 8.5″ telescope – that he was guiding by hand.

The ISS isn’t so hard to see from the ground–it’s well more than 300 feet long these days–but it is moving really, really quickly – like 17,000 miles per hour quickly.

Amazing 🙂

 

Advertisements

The largest black hole ever measured

A universal heavyweight champion was crowned this morning at the 217th meeting of the American Astronomical Society in Seattle: A giant black hole weighing a staggering 6.6 billion suns accepted the title of the most massive black hole for which a precise mass has been determined.

That’s not to say it’s necessarily the largest black hole in the universe by any means, but we haven’t measured a bigger one. Located at the heart of the galaxy M87 some 50 million light years away in the direction of Virgo, the black hole is so big it could swallow our solar system hole easily. Its event horizon – the boundary at which nothing, not even light, can escape the monster’s gravitational pull – is four times as large as the orbit of Neptune, our sun’s outermost planetary satellite.

Previous estimates of M87’s black hole mass registered at some 3 billion suns, still 1,000 times the size of the Milky Way’s welterweight black hole. The new measurements were acquired using the adaptive optics capabilities on the 26.6-foot Frederick C. Gillett Gemini Telescope on Mauna Kea, Hawaii, which can compensate for the distorting effects of Earth’s atmosphere. This allowed astronomers to gauge just how fast the stars in M87 are orbiting the black hole, and from that they could determine the mass.

If one simply compares the old measurements of M87’s black hole to it’s current massive size, it might beg the question: Is M87 juicing? Indeed, astronomers think the black hole did get some outside help beefing up over the course of its lifetime. Aside from feasting on gas and stars, M87’s champion is likely the result of a series of black hole mergers, the last of which may have happened in the not too distant past.

Whether M87’s black hole achieved its mass fairly or not, it may not hold the heavyweight title for very long anyhow. Over the next decade astronomers plan to hook up telescopes all over the world to create a whole Earth submillimeter array that will vastly increase their ability to locate event horizons and characterize the size of black holes throughout the universe.

 

Just one of many?

Just when the search for exoplanets looked like the undisputed fashionable field of study for 2010, the cosmic microwave background (CMB) is stepping to the forefront of astronomy and cosmology. Last month, it was Oxford’s Roger Penrose claiming that he’d found evidence of a cyclical universe in patterns of concentric circles in the CMB, suggesting our universe is just one of many that have come before it (and will come after it). Now, another group of researchers are claiming the CMB contains evidence of other universes that exist concurrently (and outside of) our own.

The new evidence, put forth by a group of researchers at University College London, is based upon the model of “eternal inflation,” which is predicated on the idea that our universe is part of a larger and ever-expanding multiverse. Our universe is contained in a kind of cosmic bubble that exists alongside other universes contained in their own bubbles, and in these universes the rules of physics could be far different than in our own.

If the eternal inflation theory is correct, it follows that our universe and other universes have likely collided in the past as they violently bounced around the larger multiverse, and those collisions should be evident in the CMB (the cosmic microwave background is a leftover from the Big Bang, and thus is of interest to astronomers and cosmologists for the long historical record it contains – if researchers know what to look for).

The University College team went looking for “cosmic bruises” in the CMB that indicate places where other universes collided with our own at some point, and it claims to have found them in data from the Wilkinson Microwave Anisotropy Probe
(WMAP), which has been measuring temperature differences in the CMB over the past decade. If indeed the spots are found to be “cosmic bruises,” it would lend a lot of credence to the idea that there are other universes out there that at some point collided with our own.

But that’s a big “if.” If the earlier CMB findings by Penrose are any indicator, proving or disproving these sorts of claims rooted in WMAP data is extremely difficult. Fortunately the ongoing Planck mission should soon provide a much better picture of the CMB to astronomers, allowing them to hopefully prove or disprove some of these cosmological theories. Until then, the time is ripe to attribute statistical anomalies in the vast CMB data set to complex cosmological theories.

The number of known stars triple.

In a paper published on the 1st of December in the journal Nature, astronomers from Yale and Harvard universities have found evidence for a bunch of small red dwarf stars in eight nearby galaxies. The result affects astronomers’ pictures of how stars form, how galaxies evolve, and perhaps even how much dark matter is out there.

Red dwarfs are stars like the sun, but smaller, fainter and cooler, with somewhere between one-half and one-tenth the sun’s mass. They may be small, but they are legion – astronomers estimate that red dwarfs outnumber sun-like stars in the Milky Way by a factor of 100.

Until today’s result, astronomers had been forced to assume that the 100-to-1 ratio held in other galaxies, too. But evidence has been mounting recently that elliptical galaxies – which lack the distinctive spiral arms of galaxies like the Milky Way and are usually made of older, redder stars – had more stars relative to their dark matter than spiral galaxies do.

“Within these galaxies, a good chunk of the mass that had been ascribed to dark matter is probably stars,” said Pieter van Dokkum, the lead researcher on the project.

In two papers published earlier this year, Tommaso Treu at the University of California, Santa Barbara used gravitational lensing to carefully measure how mass is distributed in 60 elliptical galaxies. He figured that some mass was missing, but that it wasn’t dark matter. Treu knew the mass was something star-like because it was distributed like the visible stars. It could be low-mass stars, or neutron stars, or even black holes. And van Dokkum set out to find out which it was.

Using a low-resolution spectrograph, which splits a galaxy’s light into its component colors, on the Keck 1 telescope in Hawaii, van Dokkum looked at eight big and bright elliptical galaxies. Seeing red dwarfs was hard – even though they far outnumber brighter stars, their collective light is still very dim. Van Dokkum and his partner, Charlie Conroy at Harvard University, looked at particular wavelengths in the near infrared, just a little longer than what the human eye can see. They were looking for signatures of sodium and iron, signatures that would tell them how many low-mass stars were contributing to the galaxy’s light.

They found that their massive elliptical galaxies probably have ten times as many low-mass stars as the Milky Way. In other words, that 100-to-1 dwarf-to-sun ratio is probably more like 1000-to-1 in big ellipticals. But there’s still plenty of dark matter, too, according to van Dokkum. In fact, the new stars probably won’t change the accounting of dark matter very much.

The next step is to see whether the excess of low-mass stars exists in lower mass galaxies, too. Van Dokkum and Treu both expect the effect to be less pronounced there.

“We could see a trend within our own sample,” said Treu. “More massive systems seem to have more of this ‘unseen’ stellar component than the lower mass objects.”

Van Dokkum will be at Keck this weekend, looking at smaller ellipticals and trying to find out.

If the result holds, it means that astronomers will need to be more careful when they calculate the number of stars in elliptical galaxies.

“It’s mostly a big headache for everybody, this result,” said van Dokkum. “But the universe doesn’t care what we hope, of course.”

Life on Mars?

NASA will hold a news conference at 2 p.m. EST on Thursday, Dec. 2, to discuss an astrobiology finding that will impact the search for evidence of extraterrestrial life. Astrobiology is the study of the origin, evolution, distribution and future of life in the universe.

You can catch the press conference here via live webstream.

Could it be? I mean, wouldn´t it be awesome if they actually announced that we´ve made contact? I wouldn´t call myself a believer, but I do enjoy the thought of not being alone. I´m not saying we´re going to find intelligent life, I´d settle with some form of bacteria, or some weird single-celled thing. As long as it´s life!

Anyway, I don´t think that´s the case. We haven´t discovered extraterrestrial life yet.