How Quickly Do Black Holes Form?

How Quickly Do Black Holes Form?


A star can burn its hydrogen for millions or even billions of years. But when the party’s over, black holes form in an instant. How long does it all take to happen.

Uh-oh! You’re right next to a black hole that’s starting to form.

In the J.J. Abrams Star Trek Universe, this ended up being a huge inconvenience for Spock as he tried to evade a ticked off lumpy forehead Romulan who’d made plenty of questionable life choices, drunk on Romulan ale and living above a tattoo parlor.

So, if you were piloting Spock’s ship towards the singularity, do you have any hope of escaping before it gets to full power? Think quickly now. This not only has implications for science, but most importantly, for the entire Star Trek reboot! Or you know, we can just create a brand new timeline. Everybody’s doing it. Retcon, ftw.

Most black holes come to be after a huge star explodes into a supernova. Usually, the force of gravity in a huge star is balanced by its radiation – the engine inside that sends out energy into space. But when the star runs out of fuel to burn, gravity quickly takes over and the star collapses. But how quickly? Ready your warp engines and hope for the best.

Here’s the bad news – there’s not much hope for Spock or his ship. A star’s collapse happens in an instant, and the star’s volume gets smaller and smaller. Your escape velocity – the energy you need to escape the star – will quickly exceed the speed of light.

You could argue there’s a moment in time where you could escape. This isn’t quite the spot to argue about Vulcan physiology, but I assume their reaction time is close to humans. It would happen faster than you could react, and you’d be boned.

But look at the bright side – maybe you’d get to discover a whole new universe. Unless of course Black holes just kill you, and aren’t sweet magical portals for you and your space dragon which you can name Spock, in honor of your Vulcan friend who couldn’t outrun a black hole.

Artist’s impression of the supergiant star Betelgeuse as it was revealed with ESO’s Very Large Telescope. Credit: ESO/L.Calçada
Artist’s impression of the supergiant star Betelgeuse as it was revealed with ESO’s Very Large Telescope. Credit: ESO/L.Calçada

Here we’ve been talking about what happens if a black hole suddenly appears beside you. The good news is, supernovae can be predicted. Not very precisely, but astronomers can say which stars are nearing the end of their lives.

Here’s an example. In the constellation Orion, Betelgeuse the bright star on the right shoulder, is expected to go supernova sometime in the next few hundred thousand years.

That’s plenty of time to get out of the way.

So: black holes are dangerous for your health, but at least there’s lots of time to move out of the way if one looks threatening. Just don’t go exploring too close!

If you were to fall through a black hole, what do you think would happen? Naw, just kidding, we all know you’d die. Why don’t you tell us what your favorite black hole sci fi story is in the comments below!

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Did a Galactic Smashup Kick Out a Supermassive Black Hole?

Near-infrared image of the dwarf galaxy Markarian 177 and what appears to be an ejected SMBH. Credit: W. M. Keck Observatory/M. Koss (ETH Zurich) et al.

Crazy things can happen when galaxies collide, as they sometimes do. Although individual stars rarely impact each other, the gravitational interactions between galaxies can pull enormous amounts of gas and dust into long streamers, spark the formation of new stars, and even kick objects out into intergalactic space altogether. This is what very well may have happened to SDSS1133, a suspected supermassive black hole found thousands of light-years away from its original home.

The two Keck 10-meter domes atop Mauna Kea. (Rick Peterson/WMKO)
The two Keck 10-meter domes atop Mauna Kea. (Rick Peterson/WMKO)

Seen above in a near-infrared image acquired with the Keck II telescope in Hawaii, SDSS1133 is the 40-light-year-wide bright source observed 2,300 light-years out from the dwarf galaxy Markarian 177, located 90 million light-years away in the constellation Ursa Major (or, to use the more familiar asterism, inside the bowl of the Big Dipper.)

The two bright spots at the disturbed core of Markarian 177 are thought to indicate recent star formation, which could have occurred in the wake of a previous collision.

“We suspect we’re seeing the aftermath of a merger of two small galaxies and their central black holes,” said Laura Blecha, an Einstein Fellow in the University of Maryland’s Department of Astronomy and a co-author of an international study of SDSS1133. “Astronomers searching for recoiling black holes have been unable to confirm a detection, so finding even one of these sources would be a major discovery.”

Interactions between supermassive black holes during a galactic collision would also result in gravitational waves, elusive phenomena predicted by Einstein that are high on astronomers’ most-wanted list of confirmed detections.

Read more: “Spotter’s Guide” to Detecting Black Hole Collisions

Watch an animation of how the suspected collision and subsequent eviction may have happened:

But besides how it got to where it is, the true nature of SDSS1133 is a mystery as well.

The persistently bright near-infrared source has been detected in observations going back at least 60 years. Whether or not SDSS1133 is indeed a supermassive black hole has yet to be determined, but if it isn’t then it’s a very unusual type of extremely massive star known as an LBV, or Luminous Blue Variable. If that is the case though, it’s peculiar even for an LBV; SDSS1133 would have had to have been continuously pouring out energy in a for over half a century until it exploded as a supernova in 2001.

To help determine exactly what SDSS1133 is, continued observations with Hubble’s Cosmic Origins Spectrograph instrument are planned for Oct. 2015.

“We found in the Pan-STARRS1 imaging that SDSS1133 has been getting significantly brighter at visible wavelengths over the last six months and that bolstered the black hole interpretation and our case to study SDSS1133 now with HST,” said Yanxia Li, a UH Manoa graduate student involved in the research.

And, based on data from NASA’s Swift mission the UV emission of SDSS1133 hasn’t changed in ten years, “not something typically seen in a young supernova remnant” according to Michael Koss, who led the study and is now an astronomer at ETH Zurich.

Regardless of what SDSS1133 turns out to be, the idea of such a massive and energetic object soaring through intergalactic space is intriguing, to say the least.

The study will be published in the Nov. 21 edition of Monthly Notices of the Royal Astronomical Society.

Source: Keck Observatory

Mysterious Object “G2” at Galactic Center is Actually Binary Star

An image from W. M. Keck Observatory near infrared data shows that G2 survived its closest approach to the black hole and continues happily on its orbit. The green circle just to its right depicts the location of the invisible supermassive black hole. Credit: Andrea Ghez, Gunther Witzel/UCLA Galactic Center Group/W. M. Keck Observatory

A mysterious object swinging around the supermassive black hole in the center our galaxy has surprised astronomers by actually surviving what many thought would be a devastating encounter. And with its survival, researchers have finally been able to solve the conundrum of what the object – known as G2 — actually is. Since G2 was discovered in 2011, there was a debate whether it was a huge cloud of hydrogen gas or a star surrounded by gas. Turns out, it was neither … or actually, all of the above, and more.

Astronomers now say that G2 is most likely a pair of binary stars that had been orbiting the black hole in tandem and merged together into an extremely large star, cloaked in gas and dust.

“G2 survived and continued happily on its orbit; a simple gas cloud would not have done that,” said Andrea Ghez from UCLA, who has led the observations of G2. “G2 was basically unaffected by the black hole. There were no fireworks.”

This was one of the “most watched” recent events in astronomy, since it was the first time astronomers have been able to view an encounter with a black hole like this in “real time.” The thought was that watching G2’s demise would not only reveal what this object was, but also provide more information on how matter behaves near black holes and how supermassive black holes “eat” and evolve.

The two Keck 10-meter domes atop Mauna Kea. (Rick Peterson/WMKO)
The two Keck 10-meter domes atop Mauna Kea. (Rick Peterson/WMKO)

Using the Keck Observatory, Ghez and her team have been able to keep an eye on G2’s movements and how the black hole’s powerful gravitational field affected it.

While some researchers initially thought G2 was a gas cloud, others argued that they weren’t seeing the amount of stretching or “spaghettification” that would be expected if this was just a cloud of gas.

As Ghez told Universe Today earlier this year, she thought it was a star. “Its orbit looks so much like the orbits of other stars,” she said. “There’s clearly some phenomenon that is happening, and there is some layer of gas that’s interacting because you see the tidal stretching, but that doesn’t prevent a star being in the center.”

Now, after watching the object the past few months, Ghez said G2 appears to be just one of an emerging class of stars near the black hole that are created because the black hole’s powerful gravity drives binary stars to merge into one. She also noted that, in our galaxy, massive stars primarily come in pairs. She says the star suffered an abrasion to its outer layer but otherwise will be fine.

Ghez explained in a UCLA press release that when two stars near the black hole merge into one, the star expands for more than 1 million years before it settles back down.

“This may be happening more than we thought. The stars at the center of the galaxy are massive and mostly binaries,” she said. “It’s possible that many of the stars we’ve been watching and not understanding may be the end product of mergers that are calm now.”

Ghez and her colleagues also determined that G2 appears to be in that inflated stage now and is still undergoing some spaghettification, where it is being elongated. At the same time, the gas at G2’s surface is being heated by stars around it, creating an enormous cloud of gas and dust that has shrouded most of the massive star.

Usually in astrophysics, timescales of events taking place are very long — not over the course of several months. But it’s important to note that G2 actually made this journey around the galactic center around 25,000 years ago. Because of the amount of time it takes light to travel, we can only now observe this event which happened long ago.

“We are seeing phenomena about black holes that you can’t watch anywhere else in the universe,” Ghez added. “We are starting to understand the physics of black holes in a way that has never been possible before.”

The research has been published in the journal Astrophysical Journal Letters.

Further reading: UCLA, Keck

The Physics Behind “Interstellar’s” Visual Effects Was So Good, it Led to a Scientific Discovery

Kip Thorne’s concept for a black hole in 'Interstellar.' Image Credit: Paramount Pictures

While he was working on the film Interstellar, executive producer Kip Thorne was tasked with creating the black hole that would be central to the plot. As a theoretical physicist, he also wanted to create something that was truly realistic and as close to the real thing as movie-goers would ever see.

On the other hand, Christopher Nolan – the film’s director – wanted to create something that would be a visually-mesmerizing experience. As you can see from the image above, they certainly succeeded as far as the aesthetics were concerned. But even more impressive was how the creation of this fictitious black hole led to an actual scientific discovery.

Continue reading “The Physics Behind “Interstellar’s” Visual Effects Was So Good, it Led to a Scientific Discovery”

What Would A Black Hole Look Like?

Artistic view of a radiating black hole. Credit: NASA

If you could see a black hole with your own eyeballs, what would you see?

Here on the Guide to Space production team: We love everything about Black Holes.

We like how they’re terrifying and completely conflict with our day to day experience of how stuff should work. We like how they completely mess you up before absolutely tearing you pieces, and we like how they ruin time and space and everything nearby.

We like them so much, we even enjoy giving them cute nick names like “Kevin”.

So I’m now going to show you images and animations of black holes.
Should you find this either too exciting or terrifying and need a breather I suggest you pause the video and walk around the block and try not to think about how absolutely terrifying these things are.

Those are just the artist’s illustrations, who’ve no doubt been awe inspired in the same way the rest of us have… but those people have never ACTUALLY seen one. Have they?

Is that what a black hole would really look like? Or are these just pictures of lasercorns?
I’ve got good news!

Here’s a picture of a real black hole. Can’t see much? That’s because it’s more than 25,000 light years away. It’s got 4 million times the mass of the Sun, and it’s still a tiny dot.

So, how do we know it’s there? The answer is awful. Even if we can’t see them directly, they make such a giant mess of things in their neighborhood we can still figure out where they are.

For an actively feeding black hole, we see a disk of material surrounding it.

This artist’s impression shows the surroundings of the supermassive black hole at the heart of the active galaxy NGC 3783 in the southern constellation of Centaurus (The Centaur). Credit: ESO/M. Kornmesser
This artist’s impression shows the surroundings of the supermassive black hole at the heart of the active galaxy NGC 3783 in the southern constellation of Centaurus (The Centaur). Credit: ESO/M. Kornmesser

Quasars are the jets emanating from active black holes, and we see them billions of light-years away. As you get closer, this area would get brighter until it was like you were close to millions of stars. The radiation would be overwhelming. Closer and closer, there would be region of total darkness, that’s the black hole itself.

For non-active or “sleepy time” black holes, we’d only see the distortion of light around them as light is bent by gravity. As you got closer and closer, there’d be less light coming from the area around the black hole. No photons can be reflected by it. You’d then pass a region called the photon sphere, where light is orbiting the black hole. You’d see the whole Universe as a swirling jumble of mixed up photons.

Next the event horizon, where light can’t escape. You could look out into the Universe and see the distorted light coming from everywhere, but the singularity itself would still be dark. Is it a single point, or a sphere? Astronomers don’t know yet.

A new telescope is in the works called the Event Horizon Telescope. It would combine the light from a worldwide constellation of radio telescopes. They’re hoping to actually image the event horizon of a black hole, and could have their first images within 5 years. Hopefully it’ll never get loaded onto a ship with Sam Neill.

Here’s hoping we’re just a few years away from knowing what black holes look like directly. But once seen, they can never be unseen. What do you think it’ll look like? tell us in the comments below!

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Hawking Radiation Replicated in a Laboratory?

In honor of Dr. Stephen Hawking, the COSMOS center will be creating the most detailed 3D mapping effort of the Universe to date. Credit: BBC, Illus.: T.Reyes

Dr. Stephen Hawking delivered a disturbing theory in 1974 that claimed black holes evaporate. He said black holes are not absolutely black and cold but rather radiate energy and do not last forever. So-called “Hawking radiation” became one of the physicist’s most famous theoretical predictions. Now, 40 years later, a researcher has announced the creation of a simulation of Hawking radiation in a laboratory setting.

The possibility of a black hole came from Einstein’s theory of General Relativity. Karl Schwarzchild in 1916 was the first to realize the possibility of a gravitational singularity with a boundary surrounding it at which light or matter entering cannot escape.

This month, Jeff Steinhauer from the Technion – Israel Institute of Technology, describes in his paper, “Observation of self-amplifying Hawking radiation in an analogue black-hole laser” in the journal Nature, how he created an analogue event horizon using a substance cooled to near absolute zero and using lasers was able to detect the emission of Hawking radiation. Could this be the first valid evidence of the existence of Hawking radiation and consequently seal the fate of all black holes?

This is not the first attempt at creating a Hawking radiation analogue in a laboratory. In 2010, an analogue was created from a block of glass, a laser, mirrors and a chilled detector (Phys. Rev. Letter, Sept 2010); no smoke accompanied the mirrors. The ultra-short pulse of intense laser light passing through the glass induced a refractive index perturbation (RIP) which functioned as an event horizon. Light was seen emitting from the RIP. Nevertheless, the results by F. Belgiorno et al. remain controversial. More experiments were still warranted.

The latest attempt at replicating Hawking radiation by Steinhauer takes a more high tech approach. He creates a Bose-Einstein condensate, an exotic state of matter at very near absolute zero temperature. Boundaries created within the condensate functioned as an event horizon. However, before going into further details, let us take a step back and consider what Steinhauer and others are trying to replicate.

Artists illustrations of black holes are guided by descriptions given from theorists. There are many illustrations. A black hole has never been seen up close. However, to have Hawking radiation all the theatrics of accretion disks and matter being funneled off a companion star are unnecessary. One just needs a black hole in the darkness of space. (Illustration: public domain)
Artists illustrations of black holes are guided by descriptions given to them by theorists. There are many illustrations. A black hole has never been seen up close. However, to have Hawking radiation, all the theatrics of accretion disks and matter being funneled off a companion star are unnecessary. Just a black hole in the darkness of space will do. (Illustration: public domain)

The recipe for the making Hawking radiation begins with a black hole. Any size black hole will do. Hawking’s theory states that smaller black holes will more rapidly radiate than larger ones and in the absence of matter falling into them – accretion, will “evaporate” much faster. Giant black holes can take longer than a million times the present age of the Universe to evaporate by way of Hawking radiation. Like a tire with a slow leak, most black holes would get you to the nearest repair station.

So you have a black hole. It has an event horizon. This horizon is also known as the Schwarzchild radius; light or matter checking into the event horizon can never check out. Or so this was the accepted understanding until Dr. Hawking’s theory upended it. And outside the event horizon is ordinary space with some caveats; consider it with some spices added. At the event horizon the force of gravity from the black hole is so extreme that it induces and magnifies quantum effects.

All of space – within us and surrounding us to the ends of the Universe includes a quantum vacuum. Everywhere in space’s quantum vacuum, virtual particle pairs are appearing and disappearing; immediately annihilating each other on extremely short time scales. With the extreme conditions at the event horizon, virtual particle and anti-particles pairs, such as, an electron and positron, are materializing. The ones that appear close enough to an event horizon can have one or the other virtual particle zapped up by the black holes gravity leaving only one particle which consequently is now free to add to the radiation emanating from around the black hole; the radiation that as a whole is what astronomers can use to detect the presence of a black hole but not directly observe it. It is the unpairing of virtual particles by the black hole at its event horizon that causes the Hawking radiation which by itself represents a net loss of mass from the black hole.

So why don’t astronomers just search in space for Hawking radiation? The problem is that the radiation is very weak and is overwhelmed by radiation produced by many other physical processes surrounding the black hole with an accretion disk. The radiation is drowned out by the chorus of energetic processes. So the most immediate possibility is to replicate Hawking radiation by using an analogue. While Hawking radiation is weak in comparison to the mass and energy of a black hole, the radiation has essentially all the time in the Universe to chip away at its parent body.

This is where the convergence of the growing understanding of black holes led to Dr. Hawking’s seminal work. Theorists including Hawking realized that despite the Quantum and Gravitational theory that is necessary to describe a black hole, black holes also behave like black bodies. They are governed by thermodynamics and are slaves to entropy. The production of Hawking radiation can be characterized as a thermodynamic process and this is what leads us back to the experimentalists. Other thermodynamic processes could be used to replicate the emission of this type of radiation.

Using the Bose-Einstein condensate in a vessel, Steinhauer directed laser beams into the delicate condensate to create an event horizon. Furthermore, his experiment creates sound waves that become trapped between two boundaries that define the event horizon. Steinhauer found that the sound waves at his analogue event horizon were amplified as happens to light in a common laser cavity but also as predicted by Dr. Hawking’s theory of black holes. Light escapes from the laser present at the analogue event horizon. Steinhauer  explains that this escaping light represents the long sought Hawking radiation.

Publication of this work in Nature underwent considerable peer review to be accepted but that alone does not validate his findings. Steinhauer’s work will now withstand even greater scrutiny. Others will attempt to duplicate his work. His lab setup is an analogue and it remains to be verified that what he is observing truly represents Hawking radiation.

References:

Observation of self-amplifying Hawking radiation in an analogue black-hole laser“, Nature Physics, 12 October 2014

“Hawking Radiation from Ultrashort Laser Pulse Filaments”, F. Belgiorno, et al., Phys. Rev. Letter, Sept 2010

“Black hole explosions?”, S. W. Hawking, et al., Nature, 01 March 1974

“The Quantum Mechanics of Black Holes”, S. W. Hawking, Scientific American, January 1977

Could A Planet Be as Big as a Star?

Could A Planet Be as Big as a Star?

How big do planets get? Can they get star sized?

Everybody wants the biggest stuff.

Soft drink sizes, SUV’s, baseball caps, hot dogs and truck nuts.

Astronomers mostly measure stars in terms of mass and use the Sun as a yard stick. This star is 3 solar masses, that star is 10 solar masses, and so on.

We’re pandering to those of you who want the most massive stuff as opposed to the most volumetric stuff. So if you want the biggest truck, but don’t care if it’s got the most truck atoms in one place, this might not be for you.

How massive can planets get, and where can I order a custom one more massive than a star?

It all depends on what your planet is made of. There are two flavors of planets, gas and rock.

Gas planets, like Saturn and Jupiter are pretty much made of the same stuff as our Sun.

Jupiter’s pretty big, but it’s actually only about 1/1000th the mass of our star. If you made it more massive. by crashing about 80 Jupiters together, you’d get the same amount of mass as the smallest possible red dwarf star.

And all that mass would compress and heat up the core and it would ignite as a star.

Artist's View of Extrasolar Planet HD 189733b
Artist’s View of Extrasolar Planet HD 189733b

Extrasolar planet astronomers have turned up some pretty massive gas planets. The most massive so far contains 28.7 times the mass of Jupiter.

That’s so massive it’s more like a brown dwarf.

But if you had a planet entirely made of rock, like the Earth. It would need to be much, much larger before its core would ignite in fusion.

It would need to be dozens of times the mass of our Sun.

Stars with 8-11 stellar masses can fuse silicon. So a rocky planet would need millions of times the mass of the Earth before it would have that kind of pressure and temperature.

So you could get a situation where you have more mass than the Sun in a rock flavored world, and it wouldn’t ignite as a star. It would get pretty warm though.

No star can burn iron. In fact, when stars develop iron in their core, that’s when they shut down suddenly and you get a supernova.

Feel free to collect all the iron in the Universe together and lump it into a ridiculously huge pile and no matter how long you stare at for, it’ll never boil or turn into a star.

It might turn into a black hole, though.

Artist's impression of Kepler-10c (foreground planet)
Artist’s impression of Kepler-10c (foreground planet)

The largest rocky planet ever discovered is Kepler 10c, with 17 times the mass of Earth.

Massive, but nowhere near the smallest star.

There’s new research that says that heavier elements blasted out of supernovae might collect within huge star forming nebulae, like gold in the eddies of a river. This metal could collect into actual stars. Perhaps 1 in 10,000 stars might be made of heavier elements, and not hydrogen and helium.

Metal stars.

So, it’s theoretically possible. There might be corners of the Universe where enough metal has collected together that you could end up with a star that’s made up of planety stuff. And that’s pretty amazing.

What do you think? If we found one of these giant metal stars, what should we call it?

And if you like what you see, come check out our Patreon page and find out how you can get these videos early while helping us bring you more great content!

Old Equations Shed New Light on Quasars

An artists illustration of the early Universe. Image Credit: NASA

There’s nothing more out of this world than quasi-stellar objects or more simply – quasars. These are the most powerful and among the most distant objects in the Universe. At their center is a black hole with the mass of a million or more Suns. And these powerhouses are fairly compact – about the size of our Solar System. Understanding how they came to be and how — or if — they evolve into the galaxies that surround us today are some of the big questions driving astronomers.

Now, a new paper by Yue Shen and Luis C. Ho – “The diversity of quasars unified by accretion and orientation” in the journal Nature confirms the importance of a mathematical derivation by the famous astrophysicist Sir Arthur Eddington during the first half of the 20th Century, in understanding not just stars but the properties of quasars, too. Ironically, Eddington did not believe black holes existed, but now his derivation, the Eddington Luminosity, can be used more reliably to determine important properties of quasars across vast stretches of space and time.

A quasar is recognized as an accreting (meaning- matter falling upon) super massive black hole at the center of an “active galaxy”. Most known quasars exist at distances that place them very early in the Universe; the most distant is at 13.9 billion light years, a mere 770 million years after the Big Bang. Somehow, quasars and the nascent galaxies surrounding them evolved into the galaxies present in the Universe today.  At their extreme distances, they are point-like, indistinguishable from a star except that the spectra of their light differ greatly from a star’s. Some would be as bright as our Sun if they were placed 33 light years away meaning that  they are over a trillion times more luminous than our star.

An artists illustration of the central engine of a Quasar. These "Quasi-stellar Objects" QSOs are now recognized as the super massive black holes at the center of emerging galaxies in the early Universe. (Photo Credit: NASA)
An artists illustration of the central engine of a quasar. These “Quasi-stellar Objects” QSOs are now recognized as the super massive black holes at the center of emerging galaxies in the early Universe. (Photo Credit: NASA)

The Eddington luminosity  defines the maximum luminosity that a star can exhibit that is in equilibrium; specifically, hydrostatic equilibrium. Extremely massive stars and black holes can exceed this limit but stars, to remain stable for long periods, are in hydrostatic equilibrium between their inward forces – gravity – and the outward electromagnetic forces. Such is the case of our star, the Sun, otherwise it would collapse or expand which in either case, would not have provided the stable source of light that has nourished life on Earth for billions of years.

Generally, scientific models often start simple, such as Bohr’s model of the hydrogen atom, and later observations can reveal intricacies that require more complex theory to explain, such as Quantum Mechanics for the atom. The Eddington luminosity and ratio could be compared to knowing the thermal efficiency and compression ratio of an internal combustion engine; by knowing such values, other properties follow.

Several other factors regarding the Eddington Luminosity are now known which are necessary to define the “modified Eddington luminosity” used today.

The new paper in Nature shows how the Eddington Luminosity helps understand the driving force behind the main sequence of quasars, and Shen and Ho call their work the missing definitive proof that quantifies the correlation of a quasar properties to a quasar’s Eddington ratio.

They used archival observational data to uncover the relationship between the strength of the optical Iron [Fe] and Oxygen[O III] emissions – strongly tied to the physical properties of the quasar’s central engine – a super-massive black hole, and the Eddington ratio. Their work provides the confidence and the correlations needed to move forward in our understanding of quasars and their relationship to the evolution of galaxies in the early Universe and up to our present epoch.

Astronomers have been studying quasars for a little over 50 years. Beginning in 1960, quasar discoveries began to accumulate but only through radio telescope observations. Then, a very accurate radio telescope measurement of Quasar 3C 273 was completed using a Lunar occultation. With this in hand, Dr. Maarten Schmidt of California Institute of Technology was able to identify the object in visible light using the 200 inch Palomar Telescope. Reviewing the strange spectral lines in its light, Schmidt reached the right conclusion that quasar spectra exhibit an extreme redshift and it was due to cosmological effects. The cosmological redshift of quasars meant that they are at a great distance from us in space and time. It also spelled the demise of the Steady-State theory of the Universe and gave further support to an expanding Universe that emanated from a singularity – the Big Bang.

Dr. Maarten Schmidt, Caltech University, with Donald Lynden-Bell, were the first recipients of the Kavli Prize in Astrophysics, “for their seminal contributions to understanding the nature of quasars”. While in high school, this author had the privilege to meet Dr. Schmidt at the Los Angeles Museum of Natural History after his presentation to a group of students. (Photo Credit: Caltech)
Dr. Maarten Schmidt, Caltech, with Donald Lynden-Bell, were the first recipients of the Kavli Prize in Astrophysics, “for their seminal contributions to understanding the nature of quasars”. While in high school, this author had the privilege to meet Dr. Schmidt at the Los Angeles Museum of Natural History after his presentation to a group of students. (Photo Credit: Caltech)

The researchers, Yue Shen and Luis C. Ho are from the Institute for Astronomy and Astrophysics at Peking University working with the Carnegie Observatories, Pasadena, California.

References and further reading:

“The diversity of quasars unified by accretion and orientation”, Yue Shen, Luis C. Ho, Sept 11, 2014, Nature

“What is a Quasar?”, Universe Today, Fraser Cain, August 12, 2013

“Interview with Maarten Schmidt”, Caltech Oral Histories, 1999

“Fifty Years of Quasars, a Symposium in honor of Maarten Schmidt”, Caltech, Sept 9, 2013

What Would It Be Like To Fall Into A Black Hole?

This artist’s impression shows the surroundings of the supermassive black hole at the heart of the active galaxy NGC 3783 in the southern constellation of Centaurus (The Centaur). Credit: ESO/M. Kornmesser

Let’s say you happened to fall into the nearest black hole? What would you experience and see? And what would the rest of the Universe see as this was happening?

Let’s say you decided to ignore some of my previous advice. You’ve just purchased yourself a space dragon from the Market on the Centauri Ringworld, strapped on your favorite chainmail codpiece and sonic sword and now you’re going ride head first into the nearest black hole.

We know it won’t take you to another world or galaxy, but what would you experience and see on your way to your inevitable demise? And what would the rest of the Universe see as this was happening, and would they point and say “eewwwwww”?

If you were falling toward a black hole, most of the time you would simply feel weightless, just as if you were playing Bowie songs and floating in a most peculiar way in the International Space Station. The gravity of a black hole is just like the gravity of any other large mass, as long as you don’t get too close. But, as we’ve agreed, you’re ignoring my advice and flying dragon first into this physics nightmare. As you get closer, the gravitational forces on various parts of your and your dragon’s body would be different. Technically this is always true, but you wouldn’t notice it… at least at first.

Suppose you were falling feet first toward a black hole. As you got closer, your feet would feel a stronger force than your head, for example. These differences in forces are called tidal forces. Because of the tidal forces it would feel as if you are being stretched head to toe, while your sides would feel like they are being pushed inward. Eventually the tidal forces would become so strong that they would rip you apart. This effect of tidal stretching is sometimes boringly referred to as spaghettification.

I’ve made up some other names for it, such as My Own Private String Cheese Incident, “the soft-serve effect” and “AAAHHHHH AHHHH MY LEGS MY LEGS!!!”.

So, let’s summarize. You wouldn’t survive falling toward a black hole because you wouldn’t listen. Why won’t you ever listen?

A friend watching you fall toward a black hole would never see you reach the black hole. As you fall towards it, gravity would cause any light coming from you to be redshifted. So as you approached the black hole you would appear more and more reddish, and your image would appear dimmer and dimmer. Your friend would see you redden and dim as you approach, but never quite reach, the event horizon of the black hole. If they could still see you past this point, there would be additional red from the inside of you clouding up the view.

Artist's conception of the event horizon of a black hole. Credit: Victor de Schwanberg/Science Photo Library
Artist’s conception of the event horizon of a black hole. Credit: Victor de Schwanberg/Science Photo Library

Hypothetically, if you could survive crossing the event horizon of a black hole, what
would you see then? Contrary to popular belief, you would not see the entire future of the universe flash before you.

What you would see is the darkness of the black hole fill your view and as you approached the event horizon you would see stars and galaxies on the edge of your view being gravitationally lensed by the black hole. The sky would simply appear more and more black until you reach the event horizon.

Many people think that it is at the event horizon where you would be ripped apart, and at the event horizon all sorts of strange things occur. Unfortunately, this goes along with those who suspect black holes are actually some sort of portal. For a solar mass black hole, the tidal forces near the event horizon can be quite large, but for a supermassive black hole they aren’t very large at all.

In fact, the larger the black hole, the weaker the tidal forces near its event horizon. So if you happened to be near a supermassive black hole, you could cross the event horizon without really noticing. Would you still be totally screwed? YOU BETCHA!

What do you think? If you could drop anything into a black hole, what would it be? Tell us in the comments below.

Observing Alert: Distant Blazar 3C 454.3 in Outburst, Visible in Amateur Telescopes

The blazar 3C 454.3 photographed by the Sloan Digital Sky Survey. It's currently in bright outburst and nearly as bright as the star next to it. Both are about magnitude +13.6. Credit: SDSS

Have an 8-inch or larger telescope? Don’t mind staying up late? Excellent. Here’s a chance to stare deeper into the known fabric of the universe than perhaps you’ve ever done before. The violent blazer  3C  454.3 is throwing a fit again, undergoing its most intense outburst seen since 2010. Normally it sleeps away the months around 17th magnitude but every few years, it can brighten up to 5 magnitudes and show in amateur telescopes. While magnitude +13 doesn’t sound impressive at first blush, consider that 3C 454.3 lies 7 billion light years from Earth. When light left the quasar, the sun and planets wouldn’t have skin in the game for another  two billion years. 

If we could see the blazar 3C 354.3 up close it would look something like this. A bright accretion disk surrounds a black hole. Twin jets of radiation beam from the center. Credit: Cosmovision
If we could see the blazar 3C 354.3 up close it would look something like this. A bright accretion disk surrounds a black hole. Twin jets of radiation beam from the center. Credit: Cosmovision

Blazars form in the the cores of active galaxies where supermassive black holes reside. Matter falling into the black hole spreads into a spinning accretion disk before spiraling down the hole like water down a bathtub drain.

Superheated to millions of degrees by gravitational compression the disk glows brilliantly across the electromagnetic spectrum. Powerful spun-up magnetic fields focus twin beams of light and energetic particles called jets that blast into space perpendicular to the disk.

Blazars and quasars are thought to be one and the same, differing only by the angle at which we see them. Quasars – far more common – are actively- munching supermassive black holes seen from the side, while in blazars – far more rare – we stare directly or nearly so into the jet like looking into the beam of a flashlight.

An all-sky view in gamma ray light made with the Fermi gamma ray telescope shows bright gamma-ray emission in the plane of the Milky Way (center), bright pulsars and super-massive black holes including the active blazar 3C 454.3 at lower left. Credit: NASA/DOE/International LAT Team
An all-sky view in gamma ray light made with the Fermi Gamma-ray Space Telescope shows bright gamma-ray emission in the plane of the Milky Way (center), bright pulsars and super-massive black holes including the active blazar 3C 454.3 at lower left. Credit: NASA/DOE/International LAT Team

3C 454.3 is one of the top ten brightest gamma ray sources in the sky seen by the Fermi Gamma-ray Space Telescope. During its last major flare in 2005, the blazar blazed with the light of 550 billion suns. That’s more stars than the entire Milky Way galaxy! It’s still not known exactly what sets off these periodic outbursts but possible causes include radiation bursts from shocked particles within the jet or precession (twisting) of the jet bringing it close to our line of sight.

3c 454.3 is near the magnitude 2.5 magnitude star Alpha Pegasi just to the west of the Great Square. Use this chart to star hop from Alpha to IM Peg (mag. ~ 5.7). Once there, the detailed map below will guide you to the blazar. Stellarium
3c 454.3 is near the star Alpha Pegasi just to the west of the Great Square. Use this chart to star hop from Alpha to IM Peg (mag. ~ 5.7). Once there, the detailed map below will guide you to the blazar. Stellarium

The current outburst began in late May when the Italian Space Agency’s AGILE satellite detected an increase in gamma rays from the blazar. Now it’s bright visually at around magnitude +13.6 and fortunately not difficult to find, located in the constellation Pegasus near the bright star Alpha Pegasi (Markab) in the lower right corner of the Great Square asterism.

Using the wide view map, find your way to IM Peg via Markab and then make a copy of the detailed map below to use at the telescope to star hop to 3C 454.3. The blazar lies immediately south of a star of similar magnitude. If you see what looks like a ‘double star’ at the location, you’ve nailed it. Incredible isn’t it to look so far into space back to when the universe was just a teenager? Blows my mind every time.

Detailed map showing the location of the blazar 3C 454.3. I've created a small asterism with a group of brighter stars with their magnitudes marked. A scale showing 30 arc minutes (1/2 degree) is at right. Stars shown to about magnitude +15. Created with Chris Marriott's SkyMap software
Detailed map showing the location of the blazar 3C 454.3. I’ve drawn a small asterism using a group of brighter stars with their magnitudes marked. A scale showing 30 arc minutes (1/2 degree) is at right. Click to enlarge. Created with Chris Marriott’s SkyMap software

To further explore 3C 454.3 and blazars vs. quasars I encourage you to visit check out Stefan Karge’s excellent Frankfurt Quasar Monitoring site.  It’s packed with great information and maps for finding the best and brightest of this rarified group of observing targets. Karge suggests that flickering of the blazar may cause it to appear somewhat brighter or fainter than the current magnitude. You’re watching a violent event subject to rapid and erratic changes. For an in-depth study of 3C 454.3, check out the scientific paper that appeared in the 2010 Astrophysical Journal.


Learn more about quasars and blazers with a bit of great humor

Finally, I came across a wonderful video while doing research for this article I thought you’d enjoy as well.