A Different Kind Of Science Show

When I visited the Cerro Tololo Inter-American Observatory a few years ago, the facility lost power. The observatory is in a remote area of northern Chile, so you can’t just call the power company to complain. Fortunately there’s a skilled team of technicians on the job. Their first priority was to maintain the cooling system of the large Blanco telescope. It contains an array of 62 CCDs known as the Dark Energy Camera, which must be kept cold. Discussing the matter in a mix of English and Spanish, the team worked through the challenge of rigging generators to the telescope. Meanwhile the CTIO kitchen staff had to figure out how to feed dozens of people without electricity. With portable gas cookers they prepare baked fish and steamed rice, with ample hot water for tea and coffee. Meanwhile, facility administrators were coordinating with the Chilean electrical grid to restore power to the observatory. By the end of the day everything was back up and running.

Whenever CTIO or other large science facilities make a breakthrough discovery, we hear about it all over the web. What we don’t hear about is the work done behind the scenes. We don’t hear about the technicians who saved a million dollar camera, or the staff who ensure that everyone is safe and fed, or the machinists who build and maintain these facilities. We also don’t hear about how these remote facilities interact with neighboring communities. How they face the challenge of being good neighbors while pursuing their scientific goals. These are stories worth telling, which is why I’ve been working on a new television project.

For about a year I’ve been working with journalist Mark Gillespie, and Canadian TV producers Steven Mitchell and Al Magee to develop a new kind of science show. One that will tell the stories behind the science headlines. Steven and Al have decades of experience in television storytelling, and have won several awards for their outstanding work. They also share my desire to present science honestly and without hype. Mark has worked in some of the most remote areas of the world, and knows how bring out stories that are meaningful and powerful.

We’ve already developed relations with many big science facilities, and we know several stories we want to tell. But in order for the project to succeed we need to film a “sizzle reel” demonstrating the show to the networks. It will be filmed on location at Green Bank Observatory. But it’s going to take some funding, so we’ve launched a Kickstarter campaign. You can find the project at https://www.kickstarter.com/projects/64470060/big-science.

Science is not just about breakthrough discoveries. It’s about people coming together to do extraordinary things. I hope you’ll help us tell this story.

How Fast is the Universe Expanding?

The Universe is expanding, but how quickly is it expanding? How far away is everything getting from everything else? And how do we know any of this anyway?

When astronomers talk about the expansion of the Universe, they usually express it in terms of the Hubble parameter. First introduced by Edwin Hubble when he demonstrated that more distant galaxies are moving away from us faster than closer ones.The best measurements for this parameter gives a value of about 68 km/s per megaparsec.

Let’s recap. Hubble. Universe. Galaxies. Leaving. Further means faster. And then I said something that sounded like “blah blah Lando blah blah Kessel Run 68 km/s per megaparsec”. Which translates to if you have a galaxy 1 megaparsec away, that’s 3.3 million light years for those of you who haven’t seen Star Wars, it would be expanding away from us at a speed of 68 km/s. So, 1 megaparsec in distance means it’s racing away at 68 km/s.

This is all because space is expanding everywhere in all places, and as a result distant galaxies appear to be expanding away from us faster than closer ones. There’s just more “space” to expand between us and them in the first place. Even better, our Universe was much more dense in the past, as a result the Hubble parameter hasn’t always had the same value.

There are two things affecting the Hubble parameter: dark energy, working to drive the Universe outwards, and matter, dark and regular flavor trying to hold it together. Pro tip: The matter side of this fight is currently losing.

Expansion of the Universe. Image credit: Eugenio Bianchi, Carlo Rovelli & Rocky Kolb.
Expansion of the Universe. Image credit: Eugenio Bianchi, Carlo Rovelli & Rocky Kolb.

Earlier in the Universe, when the Hubble parameter was smaller, matter had a stronger influence due to its higher overall density. Today dark energy is dominant, thus the Hubble parameter is larger, and this is why we talk about the Universe not only expanding but accelerating.

Our cosmos expands at about the rate at which space is expanding, and the speed at which objects expand away from us depends upon their distance. If you go far enough out, there is a distance at which objects are speeding away from us faster than the speed of light. As a result, it’s suspected that receding galaxies will cross a type of cosmological event horizon, where any evidence of their existence, not even light, would ever be able to reach us, no matter how far into the future you went.

What do you think? Is there anything out there past that cosmological event horizon line waiting to surprise us?

What is Gravitational Lensing?

Gravity’s a funny thing. Not only does it tug away at you, me, planets, moons and stars, but it can even bend light itself. And once you’re bending light, well, you’ve got yourself a telescope.

Everyone here is familiar with the practical applications of gravity. If not just from exposure to Loony Tunes, with an abundance of scenes with an anthropomorphized coyote being hurled at the ground from gravitational acceleration, giant rocks plummeting to a spot inevitably marked with an X, previously occupied by a member of the “accelerati incredibilus” family and soon to be a big squish mark containing the bodily remains of the previously mentioned Wile E. Coyote.

Despite having a very limited understanding of it, Gravity is a pretty amazing force, not just for decimating a infinitely resurrecting coyote, but for keeping our feet on the ground and our planet in just the right spot around our Sun. The force due to gravity has got a whole bag of tricks, and reaches across Universal distances. But one of its best tricks is how it acts like a lens, magnifying distant objects for astronomy.
Thanks to the general theory of relativity, we know that mass curves the space around it. The theory also predicted gravitational lensing, a side effect of light travelling along the curvature of space and time where light passing nearby a massive object is deflected slightly toward the mass.

It was first observed by Arthur Eddington and Frank Watson Dyson in 1919 during a solar eclipse. The stars close to the Sun appeared slightly out of position, showing that the light from the stars was bent, and demonstrated the effect predicted. This means the light from a distant object, such as a quasar, could be deflected around a closer object such as a galaxy. This can focus the quasar’s light in our direction, making it appear brighter and larger. So gravitational lensing acts as a kind of magnifying glass for distant objects making them easier to observe.

We can use the effect to peer deeper into the Universe than would otherwise be possible with our conventional telescopes. In fact, the most distant galaxies ever observed, ones seen just a few hundred million years after the Big Bang, were all discovered using gravitational lensing. Astronomers use gravitational microlensing to detect planets around other stars. The foreground star acts as a lens for a background star. As the star brightens up, you can detect further distortions which indicate there are planets. Even amateur telescopes are sensitive enough to spot them, and amateurs regularly help discover new planets. Unfortunately, these are one time events as this alignment happens only once.

This illustration shows how gravitational lensing works. The gravity of a large galaxy cluster is so strong, it bends, brightens and distorts the light of distant galaxies behind it. The scale has been greatly exaggerated; in reality, the distant galaxy is much further away and much smaller. Credit: NASA, ESA, L. Calcada
This illustration shows how gravitational lensing works. The gravity of a large galaxy cluster is so strong, it bends, brightens and distorts the light of distant galaxies behind it. The scale has been greatly exaggerated; in reality, the distant galaxy is much further away and much smaller. Credit: NASA, ESA, L. Calcada

There’s a special situation known as an Einstein Ring, where a more distant galaxy is warped by a nearby galaxy into a complete circle. To date a few partial rings have been seen, but no perfect Einstein Ring has ever been spotted.

Gravitational lensing also allows us to observe invisible things in our Universe. Dark matter doesn’t emit or absorb light on its own, so we can’t observe it directly. We can’t take a photo and say “Hey look, dark matter!”. However, it does have mass, and that means it can gravitationally lens light originating behind it. So we’ve even used the effect of gravitational lensing to map out dark matter in the Universe.

What about you? Where should we focus our gravitational lensing efforts to get a better look in the Universe? Tell us in the comments below.

What Came Before the Big Bang?

Illustration of the Big Bang Theory

Astronomers are pretty sure what happened after the Big Bang, but what came before? What are the leading theories for the causes of the Big Bang?

About 13.8 billion years ago the Universe started with a bang, kicked the doors in, brought fancy cheeses and a bag of ice, spiked the punch bowl and invited the new neighbors over for all-nighter to encompass all all-nighters from that point forward.
But what happened before that?

What was going on before the Big Bang? Usually, we tell the story of the Universe by starting at the Big Bang and then talking about what happened after. Similarly and completely opposite to how astronomers view the Universe… by standing in the present and looking backwards. From here, the furthest we can look back is to the cosmic microwave background, which is about 380,000 years after the big bang.

Before that we couldn’t hope to see a thing, the Universe was just too hot and dense to be transparent. Like pea soup. Soup made of delicious face burning high energy everything.
In traditional stupid earth-bound no-Tardis life unsatisfactory fashion, we can’t actually observe the origin of the Universe from our place in time and space.

Damn you… place in time and space.

Fortunately, the thinky types have come up with some ideas, and they’re all one part crazy, one part mind bendy, and 100% bananas. The first idea is that it all began as a kind of quantum fluctuation that inflated to our present universe.

Artistic view of a radiating black hole.  Credit: NASA
Artistic view of a radiating black hole. Credit: NASA

Something very, very subtle expanding over time resulting in, as an accidental byproduct, our existence. The alternate idea is that our universe began within a black hole of an older universe.
I’m gonna let you think about that one. Just let your brain simmer there.

There was universe “here”, that isn’t our universe, then that universe became a black hole… and from that black hole formed us and EVERYTHING around us. Literally, everything around us. In every direction we look, and even the stuff we just assume to be out there.

Here’s another one. We see particles popping into existence here in our Universe. What if, after an immense amount of time, a whole Universe’s worth of particles all popped into existence at the same time. Seriously… an immense amount of time, with lots and lots of “almost” universes that didn’t make the cut.

 BICEP2 Telescope at twilight at the South Pole, Antartica (Credit: Steffen Richter, Harvard University)
BICEP2 Telescope at twilight at the South Pole, Antartica (Credit: Steffen Richter, Harvard University)

More recently, the BICEP2 team observed what may be evidence of inflation in the early Universe.
Like any claim of this gravity, the result is hotly debated. If the idea of inflation is correct, it is possible that our universe is part of a much larger multiverse. And the most popular form would produce a kind of eternal inflation, where universes are springing up all the time. Ours would just happen to be one of them.

It is also possible that asking what came before the big bang is much like asking what is north of the North Pole. What looks like a beginning in need of a cause may just be due to our own perspective. We like to think of effects always having a cause, but the Universe might be an exception. The Universe might simply be. Because.

You tell us. What was going on before the party started? Let us know in the comments below.

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How are Energy and Matter the Same?

As Einstein showed us, light and matter and just aspects of the same thing. Matter is just frozen light. And light is matter on the move. How does one become the other?

Albert Einstein’s most famous equation says that energy and matter are two sides of the same coin.
But what does that really mean? And how are equations famous? I like to believe equations can be famous in the way a work of art, or a philosophy can be famous. People can have awareness of the thing, and yet never have interacted with it. They can understand that it is important, and yet not understand why it’s so significant. Which is a little too bad, as this is really a lovely mind bending idea.

The origin of E=mc2 lies in special relativity. Light has the same speed no matter what frame of reference you are in. No matter where you are, or how fast you’re going. If you were standing still at the side of the road, and observed a car traveling at ¾ light speed, you would see the light from their headlights traveling away from them at ¼ the speed of light.

But the driver of the car would still see that the light moving ahead of them at the speed of light. This is only possible if their time appears to slow down relative to you, and you and the people in the car can no longer agree on how long a second would take to pass.

Einstein's famous equation. Image via Pixabay.
Einstein’s famous equation. Image via Pixabay.

So the light appears to be moving away from them more slowly, but as they experience things more slowly it all evens out. This also affects their apparent mass. If they step on the gas, they will speed up more slowly than you would expect. It’s as if the car has more mass than you expect. So relativity requires that the faster an object moves, the more mass it appears to have. This means that somehow part of the energy of the car’s motion appears to transform into mass. Hence the origin of Einstein’s equation. How does that happen? We don’t really know. We only know that it does.

The same effect occurs with quantum particles, and not just with light. A neutron, for example, can decay into a proton, electron and anti-neutrino. The mass of these three particles is less than the mass of a neutron, so they each get some energy as well. So energy and matter are really the same thing. Completely interchangeable. And finally, Although energy and mass are related through special relativity, mass and space are related through general relativity. You can define any mass by a distance known as its Schwarzschild radius, which is the radius of a black hole of that mass. So in a way, energy, matter, space and time are all aspects of the same thing.

What do you think? Like E=mc2, what’s the most famous idea you can think of in physics?

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!

Where’s All The Antimatter?

One of the biggest mysteries in the Universe is the fact there there’s matter, and not antimatter. Where did it all go?

When we look around, everything we can see is made of matter. For every type of matter from electrons, protons and quarks there is a similar type of matter known as antimatter. So why aren’t there piles of antimatter rocks, cars and chocolate bars just lying around? Why does Scotty always have a little extra kicking around in his liquor cabinet? And where do I get mine?

The primary difference between matter and antimatter is that they have opposite electric charge. Which seems pretty mundane. The negatively charged electron has an antiparticle known as the positron, which has a positive electric charge.

Anti-protons have a negative charge, and are just flat out grumpy. We’ve been able to create these particles in the lab, and have even been able to create small amounts of anti-hydrogen consisting of a positron bound to an antiproton, when examined closely there’s were shown to have a goatee and a little colorful sash or dagger.

When we create particles in accelerators such as the Large Hadron Collider, we seem to get equal amounts of matter and antimatter. This suggests that when particles were formed soon after the big bang, there should have been equal amounts of matter and antimatter.

Particle Collider
Large Hadron Collider (CERN/LHC/GridPP)

But the universe we observe is only made of matter, and… here’s the best part… we have no idea why. Why didn’t the matter and antimatter completely annihilate each other? How come we ended up with a little more matter? This delightful mystery is known as baryon asymmetry.

We do have a few ideas, and by we, I mean some giant brained crackerjacks have come up with a few plausible options. The most popular is that somehow antimatter behaves a little differently than matter. This could cause an imbalance between matter and antimatter. After particles collided in the early universe, there would still be matter left over, hence the matter we observe.

Another idea is that the observable universe just happens to be in a region dominated by matter. Other parts of the multiverse could have observable universes dominated by antimatter. Baryon asymmetry is one of the big mysteries of modern cosmology.

Zero Gravity Flight
Stephen Hawking, weightless (courtesy Zero Gravity Corporation)

There is an even crazier idea. Antimatter might have anti-gravity. In other words, an atom of anti-hydrogen would fall up instead of down. If that is the case, then matter and antimatter would repel each other, and you might have matter universes and antimatter universes that are forever separate.There have been some initial experiments to test this idea, but so far there have been no conclusive results.

What do you think? Where’s all our antimatter and how do we track it down? I’d sure love to bring some home and show my friends…

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!

Why Doesn’t The Sun Steal The Moon?

The Sun has so much more mass than the Earth. So, so, so much more mass. Almost everything in the Solar System is orbiting the Sun, and yet, the Moon refuses to leave our side. What gives?

The Sun contains 99.8% of the entire mass of the Solar System. It looks to us like everything seems to orbit the Sun, so why doesn’t the Sun capture the Moon from Earth like a schoolyard bully snatching the Earth’s lunch money. That would make sense right? It all fits in with our skewed view of social hierarchy based on an entities volume.

Good news! It’s already happened, In a way. The Sun has already captured the Moon. If you look at the orbit of the Moon, it orbits the Sun similar to the way Earth does. Normally the motion of the Moon around the Sun is drawn as a kind of Spirograph pattern, but its actual motion is basically the same orbit as Earth with a small wobble to it.

The Moon also orbits the Earth. You might think this is because the Earth is much closer to the Moon than the Sun. After all, the strength of gravity depends not only on the mass of an object, but also on its distance from you. But this isn’t the case. The Sun is about 400 times more distant from the Moon than the Earth, but the Sun is about 330,000 times more massive.

If you’re up for some napkin calculations, you little mathlete, by using Newton’s law of gravity, you find that even with its greater distance, the Sun pulls on the Moon about twice as hard as the Earth does.
So why can’t the Moon escape the Earth?

In order to escape the gravitational pull of a body, you need to be moving fast enough *relative to that body* to escape its pull. This is known as the escape velocity of the object.

It takes two to tango. The moon’s gravity raises a pair of watery bulges in the Earth’s oceans creating the tides, while Earth's gravity stretches and compresses the moon to warm its interior. Illustration: Bob King
It takes two to tango. The moon’s gravity raises a pair of watery bulges in the Earth’s oceans creating the tides, while Earth’s gravity stretches and compresses the moon to warm its interior. Illustration: Bob King

So, yes, the Sun is totally trying to rip the Moon away from the Earth, but the Earth is super clingy.
The speed of the Moon around the Earth is about 1 km/s. At the Moon’s distance from the Earth, the escape velocity is about 1.2 km/s. The Moon simply isn’t moving fast enough to escape the Earth.

Man, those numbers sure are close. I wonder if we could kickstart a rocket to stick on the side? So, even though the Moon can’t escape the Earth, it is gradually moving away. This is due to the tidal interactions between the Earth and Moon, which we talk about another video we’ll link at the end of this one.

So even though the Moon will never escape the Earth, it will continue to move away. So, what do you think? What kind of devious project should we start to get the Moon that little boost so it finally escapes the clingy Earth and all its clingy Klingon clingyness? Tell us in the comments below.

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!

What Would A Black Hole Look Like?

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!

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!

New Results from Planck: It Doesn’t Look Good For BICEP2

One of the recent sagas in cosmology began with the BICEP2 press conference announcing evidence of early cosmic inflation. There was some controversy since the press release was held before the paper was peer reviewed. The results were eventually published in Physical Review Letters, though with a more cautious conclusion than the original press release. Now the Planck team has released more of their data. This new work hasn’t yet been peer reviewed, but it doesn’t look good for BICEP2.

As you might recall, BICEP2 analyzed light from the cosmic microwave background (CMB) looking for a type of pattern known as B-mode polarization. This is a pattern of polarized light that (theoretically) is caused by gravitational waves produced by early cosmic inflation. There’s absolutely no doubt that BICEP2 detected B-mode polarization, but that’s only half the challenge. The other half is proving that the B-mode polarization they saw was due to cosmic inflation, and not due to some other process, mainly dust. And therein lies the problem. Dust is fairly common in the Milky Way, and it can also create B-mode polarization. Because the dust is between us and the CMB, it can contaminate its B-mode signal. This is sometimes referred to as the foreground problem. To really prove you have evidence of B-mode polarization in the CMB, you must ensure that you’ve eliminated any foreground effects from your data.

When the BICEP2 results were first announced, the question of dust was immediately raised. Some researchers noted that dust particles caught in magnetic fields could produce stronger B-mode effects than originally thought. Others pointed out that part of the data BICEP2 used to distinguish foreground dust wasn’t very accurate. This is part of the reason the final results went from “We found inflation!” to “We think we’ve found inflation! (But we can’t be certain.)”

Dust effects seen by Planck (shaded region) compared with inflation results of BICEP2 (solid line).  Credit: Planck Collaboration
Dust effects seen by Planck (shaded region) compared with inflation results of BICEP2 (solid line).
Credit: Planck Collaboration

The new results from Planck chip at that claim even further. Whereas BICEP2 looked at a specific region of the sky, Planck has been gathering data across the entire sky. This means lots more data that can be used to distinguish foreground dust from a CMB signal. This new paper presented a map of the foreground dust, and a good summary can be seen in the figure. The shaded areas represents the B-mode levels due to dust at different scales. The solid line represents the B-mode distribution due to inflation as seen by BICEP2. As you can see, it matches the dust signal really well.

The simple conclusion is that the results of BICEP2 have been shown to be dust, but that isn’t quite accurate. It is possible that BICEP2 has found a mixture of dust and inflation signals, and with a better removal of foreground effects there may still be a real result. It is also possible that it’s all dust.

While this seems like bad news, it actually answers a mystery in the BICEP2 results. The level of inflation claimed by BICEP2 was actually quite large. Much larger than expected than many popular models. The fact that a good chuck of the B-mode polarization is due to dust means that inflation can’t be that large. So small inflation models are back in favor. It should also be emphasized that even if the BICEP2 results are shown to be entirely due to dust, that doesn’t mean inflation doesn’t exist. It would simply mean we have no evidence either way.

It’s tempting to look at all this with a bit of schadenfreude. Har, har, the scientists got it wrong again. But a more accurate view would be of two rival sports teams playing an excellent game. BICEP2 almost scored, but Planck rallied an excellent defense. Both teams want to be the first to score, but the other team won’t let them cheat to win. And we get to watch it happen.

Anyone who says science is boring hasn’t been paying attention.

Here’s the paper from the Planck team.

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

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.