NASA has put together a pretty cool video to celebrate Hubble Space Telescope’s 20 years in space.

If that narrator’s voice sounds familiar, that’s because it’s Brent Spiner, the actor who played Data on "Star Trek: The Next Generation". Apparently, Hubble is fully functional and programmed for multiple techniques.

People sometimes ask, “Is the universe a black hole?” Or worse, they claim: “The universe is a black hole!” No, it’s not, and it’s worth getting this one straight.

If there’s any quantitative reasoning behind the question (or claim), it comes from comparing the amount of matter within the observable universe to the radius of the observable universe, and noticing that it looks a lot like the relationship between the mass of a black hole and its Schwarzschild radius. That is: if you imagine taking all the stuff in the universe and putting it into one place, it would make a black hole the size of the universe. Slightly more formally, it looks like the the universe satisfies the hoop conjecture, so shouldn’t it form a black hole?

But a black hole is not “a place where a lot of mass has been squeezed inside its own Schwarzschild radius.” It is, as Wikipedia is happy to tell you, “a region of space from which nothing, including light, can escape.” The implication being that there is a region outside the black hole from which things could at least imagine escaping to. For the universe, there is no such outside region. So at a pretty trivial level, the universe is not a black hole.

You might say that this is picking nits, and the existence of an outside region is beside the point if the inside of our universe resembles a black hole. That’s fine, except: it doesn’t. You may have noticed that the universe is actually expanding, rather than contracting as you might expect the interior of a black hole to be. That’s because, if anything, our universe bears a passing resemblance to a white hole. Our universe (according to conventional general relativity) has a singularity in the past, out of which everything emerged, not a singularity in the future into which everything is crashing. We call that singularity the Big Bang, but it’s very similar to what we would expect from a white hole, which is just a time-reversed version of a black hole.

That insight, plus four dollars or so, will get you a grande latte at Starbucks. The spacetime solution to Einstein’s equation that describes a universe expanding from the Big Bang is very similar to the time-reversal of a black hole, but you don’t really learn much from making that statement, especially because there is no outside; everything you wanted to know was already there in the original cosmological language. Our universe is not going to collapse to a future singularity, even though the mass is enough to allow that to happen, simply because it’s expanding; the singularity you’re anticipating already happened.

Still, some folks will stubbornly insist, there has to be something deep and interesting about the fact that the radius of the observable universe is comparable to the Schwarzschild radius of an equally-sized black hole. And there is! It means the universe is spatially flat.

You can figure this out by looking at the Friedmann equation, which relates the Hubble parameter to the energy density and the spatial curvature of the universe. The radius of our observable universe is basically the Hubble length, which is the speed of light divided by the Hubble parameter. It’s a straightforward exercise to calculate the amount of mass inside a sphere whose radius is the Hubble length (M = 4π c³H^-3/3), and then calculate the corresponding Schwarzschild radius (R = 2GM/c²). You will find that the radius equals the Hubble length, if the universe is spatially flat. Voila!

Note that a spatially flat universe remains spatially flat forever, so this isn’t telling us anything about the universe now; it always has been true, and will remain always true. It’s a nice fact, but it doesn’t reveal anything about the universe that we didn’t already know by thinking about cosmology. Who wants to live inside a black hole, anyway?

Plans for the world’s largest telescope just took a major step forward. Researchers have selected a site for the European Extremely Large Telescope (E-ELT): It will sit on the Cerro Armazones mountain in central Chile’s Atacama Desert. This site beat out other contenders, including other sites in Chile and La Palma in Spain, due to its excellent conditions for astronomy.

On this desert mountain, researchers will enjoy near-perfect observing conditions – at least 320 nights a year when the sky is cloudless. The Atacama’s famous aridity means the amount of water vapour in the atmosphere is very limited, reducing further the perturbation starlight experiences as it passes through the Earth’s atmosphere [BBC]. With such clear skies, astronomer Diego Mardones from the University of Chile remarked, “If you want to find another [observation area] like Chile, your options are Antarctica or space” [Merco Press].

The telescope’s primary mirror will measure 138 feet in diameter. The mirror will be made up of 984 segments and will gather 15 times more light than the largest optical telescope while returning images 15 times sharper than those beamed back from the Hubble Space Telescope [Wired]. Astronomers say the telescope will provide new information on the nature of black holes, galaxy formation, dark matter, and dark energy.

The E-ELT, which is estimated to cost almost a billion euros, is expected to be operational by 2018. The final go-ahead for the telescope’s construction is expected later this year.

Related Content:
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80beats: In a First, Ground-Based Telescope Measures Alien Planet’s Atmosphere
80beats: World’s Biggest Telescope Will Provide “Baby Pictures” of the Universe
Image: ESO

Looking inward to the oil spill in the Gulf. Click for larger. Image credit: Jeff Schmaltz MODIS Land Rapid Response Team, NASA GSFC

Kind of a quick post, we got snow overnight – some places up to 20 inches!  The power is out and I’m trying to get this down while the generator is running.  Temperatures are forecast to reach 80 by the weekend.

You may have seen this on the news, this is the oil leak from the damaged well in the Gulf of Mexico.  The image comes from the Modis Satellite.  The latest plan I heard about was to light the oil and burn it off before any damage is done to coastal areas.

Here’s what the Modis site had to say:

An estimated 42,000 gallons of oil per day were leaking from an oil well in the Gulf of Mexico in late April, following an explosion at an offshore drilling rig on April 20, 2010. The rig eventually capsized and sank.

These images of the affected area were captured on April 25 by the MODIS on NASA’s Aqua satellite. The Mississippi Delta is at image center, and the oil slick is a silvery swirl to the right. The oil slick may be particularly obvious because it is occurring in the sunglint area, where the mirror-like reflection of the Sun off the water gives the Gulf of Mexico a washed-out look.

The initial explosion killed eleven people and injured several others, and a fire burned at the location for more than a day until the damaged oil rig sank. An emergency response effort is underway to stop the flow of oil and contain the existing slick before it reaches wildlife refuges and beaches in Louisiana and Mississippi.

The slick may contain dispersant or other chemicals that emergency responders are using to control the spread of the oil, and it is unknown how much of the 700,000 gallons of fuel that were on the oil rig burned in the fire and how much may have spilled into the water when the platform sank.

On April 25, 2010, the National Oceanic and Atmospheric Administration’s Emergency Response Division issued the following update on the Deepwater Horizon oil spill incident in the Gulf of Mexico: “An attempt to control the leaking well using a Remotely Operated Vehicle (ROV) was not successful, and the well continues to leak.”