Unexpectedly Large Black Holes and Dark Matter

The M87 black hole blasts relativistic plumes of gas 5000 ly from the centre of the galaxy (NASA)

The M87 black hole blasts relativistic plumes of gas 5000 ly from the centre of the galaxy (NASA)

I just spent 5 minutes trying to think up a title to this post. I knew what I wanted to say, but the subject is so “out there” I’m not sure if any title would be adequate. As it turns out, the title doesn’t really matter, so I opted for something more descriptive…

So what’s this about? Astronomers think they will be able to “see” a supermassive black hole in a galaxy 55 million light years away? Surely that isn’t possible. Actually, it might be.

When Very Long Baseline Interferometry is King

Back in June, I reported that radio astronomers may be able to use a future network of radio antennae as part of a very long baseline interferometry (VLBI) campaign. With enough observatories, we may be able to resolve the event horizon of the supermassive black hole lurking at the centre of the Milky Way, some 26,000 light years away from the Solar System.

The most exciting thing is that existing sub-millimeter observations of Sgr. A* (the radio source at the centre of our galaxy where the 4 million solar mass black hole lives) suggest there is some kind of active structure surrounding the black hole’s event horizon. If this is the case, a modest 7-antennae VLBI could observe dynamic flares as matter falls into the event horizon.

It would be a phenomenal scientific achievement to see a flare-up after a star is eaten by Sgr. A*, or to see the rotation of a possibly spinning black hole event horizon.

All of this may be a possibility, and through a combination of Sgr. A*’s mass and relatively close proximity to Earth, our galaxy’s supermassive black hole is predicted to have the largest apparent event horizon in the sky.

Or does it?

M87 Might be a Long Way Away, But…

As it turns out, there could be another challenger to Sgr. A*’s “largest apparent event horizon” crown. Sitting in the centre of the active galaxy called M87, 55 million light years away (that’s over 2,000 times further away than Sgr. A*), is a black hole behemoth.

M87’s supermassive black hole consumes vast amounts of matter, spewing jets of gas 5,000 light years from the core of the giant elliptical galaxy. And until now, astronomers have underestimated the size of this monster.

Karl Gebhardt (Univ. of Texas at Austin) and Thomas Jens (Max Planck Institute for Extraterrestrial Physics in Garching, Germany) took another look at M87 and weighed the galaxy by sifting through observational data with a supercomputer model. This new model accounted for the theorized halo of invisible dark matter surrounding M87. This analysis yielded a shocking result; the central supermassive black hole should have a mass of 6.4 billion Suns, double the mass of previous estimates.

Therefore, the M87 black hole is around 1,600 times more massive than our galaxy’s supermassive black hole.

A Measure for Dark Matter?

Now that the M87 black hole is much bigger than previously thought, there’s the tantalizing possibility of using the proposed VLBI to image M87’s black hole as well as Sgr. A*, as they should both have comparable event horizon dimensions when viewed from Earth.

Another possibility also comes to mind. Once an international VLBI is tested and proven to be an “event horizon telescope,” if we are able to measure the size of the M87 black hole, and its mass is confirmed to be in agreement with the Gebhardt-Jens model, perhaps we’ll have one of the first indirect methods to measure the mass of dark matter surrounding a galaxy…

Oh yes, this should be good.

UPDATE! How amiss of me, I forgot to include the best black hole tune ever:

Publication: The Black Hole Mass, Stellar Mass-to-Light Ratio, and Dark Matter Halo in M87, Karl Gebhardt et al 2009 ApJ 700 1690-1701, doi: 10.1088/0004-637X/700/2/1690.
Via: New Scientist

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District 9: Grit, Gore and Glorious Science Fiction

Wikus (Sharlto Copley) on the run from the MNU (WingNut Films).

Wikus (Sharlto Copley) on the run from the MNU (WingNut Films).

Astroengine District 9 Review.

I managed to watch District 9 last night, and it was awesome. I may as well tell you my conclusion up-front, just in case you don’t want to read on, because I’m not going to be able to avoid mentioning some spoilers. So, if you haven’t already done so, get down the theatre now to watch a unique and enthralling sci-fi docu-action-thriller (but beware, there’s lots of exploding heads and alien gore, so go easy on the popcorn and fizzy drinks).

Generally, it looks like District 9 has received good reviews and a robust nod from the science fiction community, and now I’m going to weigh in with a review from Astroengine.com.

First and foremost, I think D9 surpassed pretty much all of my expectations, which is rare for Hollywood produce these days. It was little surprise then, that this movie wasn’t of the Hollywood brand, it came from the genius mind of the South Africa-born director Neill Blomkamp and Peter Jackson‘s production company Wingnut Films. The whole thing was shot in the gritty South African city of Johannesburg.

Setting the scene

The face of a "prawn." Kinda cute in a squiddy way.

The face of a prawn. Kinda cute in a squiddy way.

An alien spaceship breaks down on Earth and comes to a stop over Johannesburg. After several weeks of not seeing any sign of life, the authorities decide to cut their way into the ship. They find hundreds of thousands of malnourished insect-like, human-sized aliens inside. Humans do the right thing by setting up a makeshift shelter in Johannesburg, called District 9 (it is of no coincidence that there’s a similarity with the real events in District Six during the 1966 apartheid government rule). So far, so good.

After a couple of decades of living in the D9 shanty town, the local human populous is getting fed up with their alien neighbours (they derogatively call “prawns”). As it turns out, these aliens don’t appear to be very smart and they are certainly not organized. They have no leader and they are thought to be the “workers” of their alien race. They are far from being the sophisticated invasion party one would expect a technologically advanced race to be like.

Alien underdogs

This is the coolest thing about this movie; the aliens are cast as the unfortunate underdogs that are being forced to stay on Earth by their human captors. Why? Technology, of course.

A military organization called Multinational United (MNU) is put in charge of moving the million-plus alien beings to a new concentration camp housing facility 200 miles away. The whole operation is led by a bumbling MNU field operative called Wikus van der Merwe (played by Sharlto Copley). Wikus is your standard trying-way-too-hard-to-please-and-failing guy with a loving wife (who can somehow see past his many social flaws) and tough father-in-law (who is the head of MNU and responsible for giving Wikus this “big break”). Wikus is almost like a South African hybrid of Steve Carrel, Steve Coogan and Simon Pegg.

Serving alien evictions. Not as easy as it sounds (it sounded easy?!)

Serving alien evictions. Not as easy as it sounds (it sounded easy?!)

There are some fantastic moments when an overly confident Wikus knocks on doors serving eviction notices to the aliens. It is an awkward, yet captivating scenario. The MNU, an organization that obviously has absolute power over the situation, has decided to make the eviction of the aliens seem “legal” by getting them to sign (or “scrawl”) their signature on a small piece of paper. Naturally, the aliens aren’t too happy about all this and Wikus is met with a variety of responses (one where the alien slaps the paper out of his hand and storms off — Wikus triumphantly points out that a tentacle hit the paper, it is therefore signed). Another funny legality is that the aliens have been given human names (such as “Christopher Johnson”) to make their very existence bona fide.

In the first third of the film there are several reminders that the MNU isn’t a tolerant organization. If the armed units are faced with any resistance, they kill on-site. However, they are faced with an impoverished, desparate alien populous that will do anything for a tin of cat food. They are more concerned about chewing on car tires than being shot at. The cat food actually becomes a commodity in District 9, a currency the local Nigerian gangs use to trade for weapons. There is also a hilarious reference to “inter-species prostitution.”

Human-prawn hybrid?

The movie starts off in hand-held documentary style (not in an annoying Blair Witch Project way), following Wikus on his alien eviction adventures, but the atmosphere of the story changes after he accidentally sprays himself in the face with a black fluid in an unidentified cylinder. There is then an altercation with one of “Christopher Johnson’s” friends who tries to distract attention away from the shack that contained Wikus was sprayed in.

Cue alien death, execution style, by the bald-headed bad-ass special unit military guy.

A dodgy stomach and a broken arm later, Wikus is stuck in a situation he can’t get out of. You remember that spray? It turns out that it’s not only a special, highly refined spaceship fuel, it’s also a way to really mess up your day if you breathe it in. Wikus has started to change into an alien.

This is probably one of the weaker parts of the story. How a nasal spray is going to tinker with your genetics in such a way that will turn you into a human-alien hybrid, I don’t know, but District 9 didn’t start with a claim that it was going to be totally scientifically accurate. Somehow Wikus’ left hand also turns into a clawed alien appendage. I’ll turn a blind eye to the fudged human-alien biology lesson.

Guards outside the grim District 9

Guards outside the grim District 9

So we’re locked in a race against time as MNU agents track down and capture Wikus as Wikus becomes more and more prawn-like. From being a flawed MNU officer, he has now become the most valuable human on the planet; he is the only one capable of operating the alien technology (their weapons only react to alien biology).

Prawn purée

During the period when Wikus has been captured and is being experimented on, the MNU shows itself for what it really is; a weapon research facility with little regard for human life, let alone alien life. In one particularly tough scene, Wikus has to fire an assortment of alien weaponry at animal carcasses against his will…

[If you told me before watching District 9 that I would feel shocked by the death of a CGI’d alien being, I’d assume I would have been drinking heavily beforehand. But no, I hadn’t had a beer (although the Pepsi was quite syrupy).]

…At this point, a live alien is dragged out with an X painted on its torso. When stood, shivering at the end of the shooting range, Wikus is ordered to shoot the alien. He refuses, crying. You see that Wikus does have a certain degree of respect for the aliens and he is certainly adverse to killing them. Unfortunately, tied in place, and alien weapon pushed in this hand, he’s forced to fire the gun at the frightened “prawn,” who explodes in a bloody mess.

It’s pretty grizzly and also a little upsetting. I think this is the moment in the movie that you know you are dealing with a different kind of sci-fi storyline and Blomkamp does an amazing job to shock, but not to go over the top.

Agony and terror

Christopher Johnson looks out of the prison van after being captured.

Christopher Johnson looks out of the prison van after being captured.

Also, you realize Sharlto Copley’s acting ability is nothing short of outstanding. Before the weapon testing scene, there’s a fair amount of humour angled at his character, afterwards you can feel his agony and terror.

Needless to say, Wikus escapes and runs to the only place he can find refuge: District 9. Fortunately, we are allowed a little time to recuperate after the MNU experiments as Wikus turns into a convict running through his own city.

After a period of making friends with the smart “Christopher Johnson” and little (and quite cute) pint-sized alien son, Wikus and “Christopher” work out they need each other to find a solution to the problems they are facing. “Christopher” needs to retrieve the mysterious cylinder from the MNU HQ to make the command ship (hidden under District 9) function, and Wikus needs alien technology from the mothership hovering overhead to stop him from going 100% prawn.

And so begins an orgy of human-popping. In the best human-alien buddy pairing since Han Solo and Chewbacca, Wikus and “Christopher” assault the MNU HQ with the best alien guns Wikus could steal from those Nigerian “inter-species prostitution” gangs (with a fetish for drinking alien blood and collecting alien junk they can’t use). Of course, now that Wikus can operate these guns, he can have some fun.

A clip from District 9: Wikus uses an alien weapon for the first time (language NSFW):

Many reviews of District 9 are critical of the amount of action in the rest of the film, but I thought it was pretty cool. Science-lite, but it sure was a tour de force of movie action imagination. My particular favourite was Wikus’ energy-lightning-bolt gun that had no difficulty in snuffing out MNU personnel in a cloud of blood vapour.

A few gun battles later, and we return to District 9, plus fuel cylinder. Quite a lot happens, but to cut a long story short… there were a lot of explosions. I don’t want to give away the ending, but it was fairly routine, with a couple of minor plot twists. When I say routine, I don’t mean it was boring, the movie simply went its course without too many surprises. Well, there might have been one or two

Banff Ground Squirrel Witnessed Apollo 11 Landing

Buzz Aldrin poses for Armstrong's camera in 1969. Little did the astronauts realize... they were being watched... (NASA/NatGeo/Ian O'Neill)

Buzz Aldrin poses for Armstrong's camera in 1969. Little did the astronauts realize... they were being watched... (NASA/NatGeo/Ian O'Neill)

Ever wonder why some of the Apollo lunar landing shots are a little out of focus? Ever wonder why chunks of photographs from the Moon have been cut out, leaving a a little squirrel-like shape behind?

Wonder no more, even the Moon has a colony of ground squirrels (plus mini-space helmets, of course), ready to pop out of hiding when they feel the vibration of lunar lander thrusters, astronaut footsteps, and the whine of focusing cameras. This is one Moon conspiracy solved, once and for all!

Don’t worry, I haven’t lost it quite yet, I’ve just been playing with Photoshop. This is in response to the wonderful National Geographic photograph of a curious ground squirrel that managed to pose for the perfect holiday snap in Canada’s Banff National Park. Now the image is going viral, with little squirrel cut-outs appearing in a huge range of photos and videos.

So here’s my effort. The Banff Lunar Squirrel!

Amateur Captures Solar Eclipse, By Io… On Ganymede

io-ganymede-shadow-still

Of all the amazing things I plan to look at through my future telescope (yes, I’m still saving), this event didn’t even cross my mind. Not surprising really, it’s probably never been observed before: Io’s whole shadow transiting across the large Jovian moon, Ganymede.

But on August 16th, that changed when Christopher Go from Cebu, Philippines used his 11-inch Celestron telescope to capture the sequence of events as Io passed in front of the Sun, casting a near-perfect shadow on the large moon of Ganymede. If you were standing on Ganymede’s surface, looking at the Sun, you would have seen an Io solar eclipse.

io-gann-eclipse

My favourite thing about this animation is that both moons are very detailed, even at this resolution. You can see mottled shades on Ganymede, and I think the spin of Io may even have been captured.

A wonderful testament to Christopher Go’s astronomy skills and a fantastic example of how advanced our amateur astronomical equipment is becoming…

Source: Spaceweather.com

UPDATE: It turns out that little Io is getting its own back for last July’s eclipse by Ganymede, plunging the smaller moon into darkness. In the following video by OccultDave on YouTube, over a period of about 16 minutes, Io (the dot to the far-right) dims dramatically as Ganymede (the dot in the middle, next to the bright disk of Jupiter) blocks the sunlight:

Let The Planet Seeding Begin! Comets Have Amino Acids Too…

comet_tempel

Yesterday, NASA announced exciting news about a discovery made by a NASA mission that did a cosmic dance with comet Wild 2 back in 2004. The Stardust mission managed to scoop an amino acid called glycine from the comets dusty tail, thereby proving it’s not just asteroids that contain this critical ingredient for life.

It’s not a particularly unexpected discovery that glycine is in a comet — we’ve found amino acids in meteorites before — but it does show that comets are another way that amino acids could have come to Earth,” lead researcher Jamie Elsila, with NASA’s Goddard Space Flight Center, told Irene Klotz from Discovery News.

Elsila and colleagues are responsible for developing a technique to extract and study the deposits of glycine from the aluminium foil that lined the probe’s collection plates. They confirmed the glycine was in fact of extraterrestrial origin (rather than contamination here on Earth), as the carbon atoms in the glycine molecules had an extra neutron in the nucleus. This means the glycine was formed in space.

We see in this comet that amino acids were forming at the earliest time in our solar system,” Mike Zolensky, a comet dust researcher from NASA’s Johnson Space Center in Houston, said.

Zolensky suspects that heat from the radioactive decay of short-lived particles melted a piece of comet ice laced with organic compounds and water. This may have allowed the cosmic amino acid to form.

Now that an amino acid has been scraped off the collection plate of the Stardust mission, it would appear the building blocks for life are widely available throughout the Solar System (assuming comet Wild 2 isn’t a special case). Asteroids contain amino acids, as do meteorites, now it looks as if comets carry the building blocks for life too. This means early-Earth certainly had plenty of opportunities to acquire extra-terrestrial sources of amino acids…

Source: Irene Klotz, Discovery News Space Correspondent

Deconstructing Doomsday

Alex Young in front of the cameras in the post-Apocalyptic setting of a Brooklyn building site.

Alex Young in front of the cameras in the post-Apocalyptic setting of a Brooklyn building site.

The funny thing about being involved in a doomsday documentary is trying to find a suitable balance between entertainment and science. This is the conclusion I reached after the interview I did for KPI productions in New York for the upcoming 2012 documentary on the Discovery Channel last week (just in case you were wondering why Astroengine.com was being a little quiet these last few days).

Apparently, the Apocalypse will be very dusty.

Apparently, the Apocalypse will be very dusty.

Naturally, the production team was angling for what it might be like to be hit by a “killer” solar flare, what kinds of terror and destruction a brown dwarf could do to Earth and what would happen if our planet’s magnetic poles decided to do a 180°. It’s always fun to speculate after all. However, I wasn’t there to promote half-baked theories of 2012 doom, I was there to bring some reality to the nonsensical doomsday claims. But with real science comes some unexpected concerns for the safety of our planet — not in 2012, but sometime in the future.

An added bonus to my NYC trip was meeting the awesome Alex Young, a solar physicist from NASA’s Goddard Space Flight Center. Alex was asked to New York for the same reasons I was, but he has a current and comprehensive understanding of solar dynamics (whereas my solar physics research is so 2006). He actually works with SOHO data, a mission I have massive respect for.

Alex Young and myself... very excited about doomsday.

Alex Young and myself... very excited about doomsday.

My interview was carried out on Wednesday morning, and Alex’s was in the afternoon. The KPI guys were great, a joy to be involved in such a professional project. The documentary producer, Jonathan, asked me the questions in a great location, a huge Brooklyn building that was undergoing renovation. Very dusty with a post-apocalyptic twist. If I was going to shoot a movie about the end of the world, this building would be it.

The KPI documentary will certainly be very different from the Penn & Teller: Bullshit! episode I was involved with, but it was just as much fun, if not more so (it was like a day-long science fest).

Of particular note was Alex’s sobering words about the woeful lack of funds in solar physics (i.e. Earth-damaging solar flares and CMEs). I hope his closing statement about NOAA space weather prediction funding makes the final cut; it was nothing less than chilling.

Jon and Sarah from KPI on the set.

Jon and Sarah from KPI on the set.

Although we both hammered home the point that the fabled Earth-killing solar flare wont happen in 2012 (let’s face it, our Sun is still going through an epic depression, why should solar maximum be anything spectacular?), it is probably the one theory that holds the most scientific merit. In fact, as both Alex and I agreed, for a civilization that depends on sensitive technology in space and on the ground, we really need to prepare for and understand solar storms far better than we do at present.

I won’t go into any more details, but the documentary will be on the Discovery Channel in November, so I’ll give plenty of warning to fire up those DVRs.

Thank you Sarah, Jonathan and the rest of the crew from KPI for making the New York visit so memorable…

The Naked Singularity Recipe: Spin a Black Hole, Add Mass

naked_singularity

The event horizon of a black hole is the point of no return. If anything, even light, strays within the bounds of this gravitational trap, it will never escape. The event horizon is what makes a black hole black.

But say if there was a way to remove the event horizon, leaving just the black hole’s singularity to be “seen” by the rest of the universe? What if there is a special condition that would allow this infinitely small, yet massive point to become naked?

Generally physicists agree that this is a physical impossibility, but the mathematics says otherwise; a naked singularity could be possible.

Previously on Astroengine, one “special condition” was investigated when an extreme black hole collision was simulated by a Caltech researcher. In this case, the black hole pair was smashed together, head-on, at a velocity close to the speed of light. The gravitational waves travelling away from the collision were then modelled and characterized. It turns out that after this insanely energetic impact, 14% of the total mass was converted into gravitational wave energy and both black holes merged as one.

While this might not be very realistic, it proved to be a very useful diagnostic tool to understand the conditions after the collision of two black holes. As an interesting observation, the Caltech researchers found that although the collision was extreme, and there was a huge amount of mass-energy conversion going on (plus, I’d imagine, a rather big explosion), neither black hole lost their event horizons.

Case closed, wouldn’t you think?

Actually, another theory as to how a black hole could be stripped naked has been knocking around for some time; what if you added mass to a black hole spinning at its maximum possible rate? Could the black hole be disrupted enough to shed its event horizon?

It turns out there’s a natural braking system that prevents this from happening. As soon as mass is dropped into the black hole, it is flung out of the event horizon by the black hole’s huge centrifugal force, preventing it from coming close to the singularity.

However, Ted Jacobson and Thomas Sotiriou at the University of Maryland at College Park have now improved upon this idea, sending mass in the same direction as the spinning black hole. Only this time, the black hole isn’t spinning at its fastest possible rate, the simulation lets the orbiting matter fall into the event horizon, speeding up its spin. The result? It appears to disrupt the black hole enough to strip away the event horizon, exposing the singularity.

The most interesting thing to come of this research is that swirling matter is falling into black holes all over the universe, speeding up their spin. Jacobson and Sotiriou may have stumbled on a viable mechanism that actually allows naked singularities in the cosmos. Unless nature has found another way to prevent the cosmic censorship hypothesis from being violated that is…

Source: New Scientist