Largest Black Holes Ever Discovered

Researchers have discovered two black holes larger than any we’ve ever seen before, almost 10 billion times the size of our sun, which makes them about 10,000,000,000,000,000 (10 quintillion) times the size of the Earth. As with most things cosmic or quantum, if it’s unimaginable then you’re probably thinking of it right.

From Scientific American:

The scientists used the Gemini and Keck observatories in Hawaii and the McDonald Observatory in Texas to monitor the velocities of stars orbiting around the centers of a pair of galaxies. These velocities reveal the strength of the gravitational pull on those stars, which in turn is linked with the masses of the black holes lurking there.

The new findings suggest that one galaxy, known as NGC 3842, the brightest galaxy in the Leo cluster of galaxies nearly 320 million light years distant, has a central black hole 9.7 billion solar masses large. The other, named NGC 4889, the brightest galaxy in the Coma cluster more than 335 million light years away, has a black hole of comparable or larger mass. Both encompass regions or “event horizons” about five times the distance from the sun to Pluto…

Astronomers had suspected that black holes more than 10 billion solar masses large exist, based on light from quasars, cosmic objects from the early universe that are no more than a light year or two across but are thousands of times brighter than our entire galaxy.

The light of quasars is thought to come from matter driven to incandescent brightness as it spirals at high speeds into supermassive black holes. This is the first time scientists have detected black holes approaching such theorized giants in size.

“These two new supermassive black holes are similar in mass to young quasars, and may be the missing link between quasars and the supermassive black holes we see today,” said study co-author Chung-Pei Ma, an astrophysicist at the University of California, Berkeley.

The “event horizon” mentioned is the space in which gravity is too strong for anything to escape, including light.

Quasars are regions around the center of some galaxies that glow extremely brightly; they can output far more light than an entire galaxy while being about the size of our solar system. They acquire this energy from the supermassive black holes around which they revolve, or rather from all of the matter getting pulled into and around the black holes, heating up as they go. The incredible brightness of quasars implied incredibly huge black holes, and now scientists have seen some evidence of that.

Fun fact: the largest known quasar’s black hole is estimated to consume the equivalent of 600 Earths per minute. That’s a hungry hungry black hole. Quasars were also mentioned in the news about 12 billion-year-old primordial gas clouds being discovered; the clouds were discovered because of how the light from more distant quasars passed through them. The reason quasars are particularly important in that context is because we can see them from so far away/long ago, because of their incredible brightness. It all comes back to hungry hungry black holes in the end I guess. 

The Path to Manned Flight to Mars

Scientific American has a pretty fascinating article by a NASA mission architect and mission analyst discussing NASA’s future and how to, eventually, put humans on Mars. In 2009, a group of NASA scientists began brainstorming how to move forward with human space exploration, in light of the ending of the Space Shuttle program and, in 2010, the cancellation of the Constellation program that was meant to replace it. 

After some years of plotting:

We have now combined the most promising proposals with tried-and-true strategies to develop a plan to send astronauts to the near-Earth asteroid 2008 EV5 as soon as 2024 as preparation for an eventual Mars landing. This approach is designed to fit within NASA’s current budget and, crucially, breaks the overall task into a series of incremental milestones, giving the agency flexibility to speed up or slow down depending on funding. In a nutshell, the aim is to apply lessons from the robotic scientific exploration program to renew the human exploration one.

The article is rather extensive, but worth the read if you want to see what goes on in the imaginations of rocket scientists tasked with dreaming up all things awesome. It’s also a nice primer on the kinds of techniques and technologies involved in space travel, something we don’t generally think about too much. They also have a video of the authors discussing their idea, or as a shortcut to all of this, a pretty cool graphic explaining how this manned space flight is going to work.

Two things to note are that 1) instead of using space suits outside of the ship as we’re used to, with all their limited mobility, they’d instead want the astronauts to command little vehicular pods when on the asteroid surface (and presumably Mars, later). 2) is that they want to use an ion drive instead of rockets to travel through space, for weight and energy reasons. Ion thrusters basically create charged atoms (ions) and shoot them out using an opposite electric charge, creating thrust that will push the ship in the opposite direction.  

The most important point underlying these ideas, as they said above, is that progress towards landing on Mars will be incremental, involving a number of shorter trips in the meantime. In an ideal world they’d have the funding to go for broke, but they’ll have to make do for now. 

Giant Lake Discovered on Jupiter’s Moon Europa

From National Geographic:

Hidden inside the thick, icy crust of Jupiter’s moon Europa may be a giant saltwater body equal to the Great Lakes combined, NASA announced today.

Lying about 1.9 miles (3 kilometers) from the surface, the ice-trapped lake may represent the newest potentially habitable environment in the solar system—and one of the best prospects for the search for life beyond Earth.

“For decades scientists have thought Jupiter’s moon Europa was a likely place for life, but now we have specific, exciting regions on the icy moon to focus our future studies,” Don Blankenship, senior research scientist at the University of Texas at Austin’s Institute for Geophysics, told National Geographic News…

Similar in size to Earth’s moon, Europa is already thought to house a global, salty ocean beneath its 62-mile-thick (100-kilometer-thick) ice shell. NASA’s Galileo spacecraft, which orbited Jupiter and its moons from 1995 to 2003, first discovered evidence of the ocean…

There probably are many more lakes under Europa’s ice, Blankenship added.

Likewise, the prospects for searching for life on Europa could improve dramatically, as research suggests some of these icy lids covering the lakes may be much thinner than thought.

The techniques they used to infer the existence of the lake are the same that they use with satellite imagery of Earth, for example to discover subglacial lakes in Antarctica.

So when will we finally find out if there’s life on Europa? Uh… not any time soon, it seems. NASA planned a mission to specifically check out Europa using a probe called the Jupiter Icy Moons Orbiter (JIMO), but that plan was scrapped in 2005. This August, NASA launched a probe called Juno to investigate Jupiter; it will arrive around 2016. Taking more peeks at Europa does not seem to be in its job description, but who knows what it might see?

Fun facts: Juno will travel a total of 1.74 billion miles, or 2.8 billion kilometres. If that’s impossible to imagine, well, it should be. Meanwhile, the farthest probe from Earth is the Voyager 1, at 119 AU (an AU being the average distance from Earth to the sun), or almost 18 billion kilometres away. It was launched in 1977 and is still in communication with Earth. 

This news caught my attention because I was just reading about 2001: A Space Odyssey, and the sequels to that novel are based on there being life on Europa. What else did Arthur C. Clarke know that we don’t?

A Giant Planet Ejected From Our Solar System

Based on studying the lunar craters and the bodies in the Kuiper belt beyond Neptune, scientists have deduced that something big happened in our solar system when it was about 600 million years old, throwing off the orbits of the giant planets and sending smaller bodies flying every which way, including to impact the moon. Now one astronomer showed that the best model for how this could occur involves having a fifth giant planet that was ejected from our solar system.

This means that the early sky from an Earth viewpoint 4 billion years ago would’ve been rather different – having another planet in the sky, having the gas giants in different orbits, and having a much less dinged up moon, at least. If you ever time travel to the dawn of life on Earth, remember not to be too startled by this. 

You can read the full deal on this at Wired or see the press release from the Southwest Research Institute. Wired has a related article from May about the discovery of “orphan planets,” planets wandering the galaxy without a star to orbit. Maybe we can see our orphaned planet out there? 

Our neighbours in the solar system. The interplanetary distances are definitely not to scale, and not depicted are the other 334 moons in the solar system (168 around the planets). Image courtesy of jasonirwin.ca.

While we’re here, let’s see what Wikipedia can teach us about the Kuiper belt. You’ve probably heard of the asteroid belt, which is a region between Mars and Jupiter occupied by, naturally, a lot of asteroids. It’s the division between the four inner and four outer planets, or the terrestrial planets and the gas giants. About a third of the mass of the asteroid belt is in Ceres, the solar system’s smallest dwarf planet and largest asteroid, which is about 950 km in diameter. A space probe from NASA was launched in 2007 and will investigate Ceres in 2015.

Meanwhile, the Kuiper belt is past Neptune, the farthest planet in the solar system, and is about 20 times as wide as the asteroid belt. Its existence was first hypothesized in 1930 shortly after the discovery of Pluto, by an astronomer who thought Pluto looked awfully lonely. Starting in 1992, he was proven right as asteroids in the Kuiper belt were discovered. Now there are four bodies labeled as dwarf planets in the Kuiper belt – Pluto, Eris, Makemake, and Haumea, although more may be added in the future.

The more scientists learned about the Kuiper belt – particularly the discovery of Eris, which is larger than Pluto – the harder it was to maintain that Pluto was, in fact, a planet comparable to the others, leading to its downgrading in 2006 and the creation of the “dwarf planet” classification. Although this upset quite a few people, it’s not the first time this has happened – asteroids used to be classified as planets before we discovered how many of them there were, in the early 1800s. The asteroids that were once considered planets are Ceres, Pallas, Juno and Vesta, all in the asteroid belt. 

I guess the lesson in all this is that there’s a lot going on in the solar system, and we have a lot to learn about our neighbourhood, so don’t get too emotionally attached to your solar system model. If you thought downgrading Pluto from a planet to a dwarf planet was sad, imagine how people in the 1500s felt about downgrading Earth from the center of the universe to a planet. Oh the Facebook groups they would have made…

Deflecting an Asteroid

You may have heard that an asteroid passed close to the Earth this week; here’s a video of it traveling through the sky, recorded by an astronomer named BJ Fulton and found via Astronomy Blog:

As a result of this fly-by there’s been a lot of asteroid talk lately, and Universe Today has a very interesting article on what our options would be if an asteroid were in fact on a collision course with Earth. All it might take is an asteroid 1 kilometre in diameter to end human civilization, apparently, which really sucks. Here’s Wikipedia’s description of the likely effects of the asteroid that created the Chicxulub crater and possibly contributed to the extinction of dinosaurs (“the Cretacious-Paleogene extinction event”):

The impact would have caused some of the largest megatsunamis in Earth’s history, reaching thousands of meters high. A cloud of super-heated dust, ash and steam would have spread from the crater, as the impactor burrowed underground in less than a second. Excavated material along with pieces of the impactor, ejected out of the atmosphere by the blast, would have been heated to incandescence upon re-entry, broiling the Earth’s surface and possibly igniting global wildfires; meanwhile, colossal shock waves would have effected global earthquakes and volcanic eruptions. The emission of dust and particles could have covered the entire surface of the Earth for several years, possibly a decade, creating a harsh environment for living things. The shock production of carbon dioxide caused by the destruction of carbonate rocks would have led to a sudden greenhouse effect. Over a longer period, sunlight would have been blocked from reaching the surface of the earth by the dust particles in the atmosphere, cooling the surface dramatically. Photosynthesis by plants would also have been interrupted, affecting the entire food chain.

So, that sounds like a lot of fun. The asteroid in question was over 10 km in diameter, but I think an effect a tenth that size might still be problematic. So how do we stop that from happening? The article from Universe Today has some interesting answers that I can’t do justice to here – you should read it for yourself for the full scoop.

Some of the possibilities it mentions for changing an asteroid’s course are hitting it with nuclear weapons (which would be legally problematic due to space treaties), using a solar-energy-powered sail, tying ballast to it, or vaporizing part of it with lasers. Any of these schemes would take extensive planning and cooperation, so it seems that preparing for them immediately would be the safest course of action. 

It may be bad to say, but I kind of want to see this crisis happen, just to see the science jump-started and thrown into full gear. I see a supervillain motivation here, actually…

Pure Clouds From the Big Bang

For the first time, astronomers have discovered clouds of gas that apparently do not contain any elements created by stars – they exist as they were created minutes after the Big Bang. Or at least they did about 12 billion years ago, since they’re about 12 billion light years away – but that’s still 2 billion years after the Big Bang. 

From PhysicsWorld

Just after the Big Bang, nuclear reactions created the three lightest elements – hydrogen, helium, and a tiny bit of lithium. Stars then converted some of this material into the heavy elements such as carbon and oxygen that pepper the cosmos today.

But no-one has ever seen a star or gas cloud made solely of these three Big Bang elements. Instead, all known stars and gas clouds harbour at least some “metals”, the term astronomers use to describe any element, even carbon and oxygen, that is heavier than helium…

Now, Michele Fumagalli and Xavier Prochaska of the University of California, Santa Cruz and John O’Meara of Saint Michael’s College in Vermont, have found two pristine gas clouds. “Their chemical composition is unusual,” says Fumagalli. “This gas is of primordial composition, as it was produced during the first few minutes after the Big Bang.”

… The clouds are far too faint to observe directly. Fumagalli and colleagues discovered them only because the clouds happen to lie in front of even more distant quasars, which are luminous galaxies that were much more common long ago. Atoms in the gas clouds absorb some of the light from the background quasars, and the wavelengths at which absorption is evident reveals important information about the composition of the clouds…

Despite using the mammoth Keck I telescope atop Mauna Kea in Hawaii, the astronomers failed to find any element except hydrogen in the two clouds. While the researchers also expect helium and lithium to be present, their technique is not sensitive to those elements. However, if oxygen, carbon or silicon were present, it should have been easy to spot…

“It’s a very interesting discovery,” says Nick Gnedin, an astronomer at Fermilab in the US, who is unaffiliated with the discovery team. Gnedin says it has been very difficult to understand why all other gas clouds – even those at greater distances – contain metals. These newfound exceptions should help astronomers understand why all other gas clouds contain metals, he says…

In addition to ordinary hydrogen, Fumagalli and colleagues detected the hydrogen isotope deuterium in the Ursa Major cloud. Physicists believe that the Big Bang produced deuterium but that stars then destroyed it – so the universe once had more deuterium than it does today.

(I briefly talked about isotopes in an earlier post: the difference between deuterium and normal hydrogen is that deuterium has a neutron in addition to a normal hydrogen atom’s proton and electron. Deuterium exists in nature still, but in relatively small amounts.)

The high deuterium-to-hydrogen ratio in the gas matches Big Bang predictions. “The fact that we see deuterium that is comparable to what is expected from theory is giving us more confidence that this gas is actually primordial in its composition,” says Fumagalli.

This discovery is pretty interesting, and I would bet that studying these clouds and others like them will teach us a lot about the ancient universe. I will prepare myself for future bombshells.

This isn’t a particularly relevant place to say it, but it still boggles my mind that we can detect things from that far away, and consequently from that long ago. Astronomers time travel further back than any science fiction writer could’ve imagined – and I suppose we do too when we look into the sky, to a lesser degree. We take it for granted now, but it’s truly incredible.

Update: For a very enthusiastic explanation of why the elemental composition of these clouds is predicted by the Big Bang, check out this article from Starts With a Bang

Floating in the ISS

Here’s a video (via Gizmodo) of some astronauts showing the magic of acceleration in the International Space Station to the world. It has nothing to do with anything really, but it’s interesting to see astronauts seemingly enjoying themselves quite a bit. This is more striking considering one is American, one is Russian and one is Japanese – it makes the ISS look like an international summer camp or something.

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