Guide to Space Archives

November 3, 2014March 1, 2017 by Fraser Cain

How Does a Rocket Work?

Rockets are the perfect way to get around in space. But how do they work?

Space travel and rockets, it’s like ice cream and apple pie, or ice cream and apple pie and my face. They just go together. They belong together.

But what if I’m allergic to rockets, or have some kind of cylindrical intolerance, or flaming column sensitivity that makes me hive out? Why can’t I fly to space in balloons or airplanes or helicopters? Why do we need these pointy cubist eggplant flame tubes?

The space age followed the development of powerful V2 rockets in WW II. They could hit targets 320 km away and reach an altitude of 200 km. They were a new kind of war machine, a terrifying weapon that could hurl payloads of destruction from the skies. But this terrifying development is what brought us our modern rockets as their propulsion system can work up where there’s no air, in the vacuum of space.

How do they actually work? It all comes down to that “every action, equal and opposite reaction” thing that Newton was always going on about.

If you take a balloon, fill it with air, and then let it go. All that air rushing out propels the balloon around. This kind of balloon rocket would work perfectly well in space too although it might be a little too fragile and unpredictable to want to strap yourself to.

If we take that idea and scale it up, add some fuel tanks and fins, attitude control and optionally: astronauts. We’ve got ourselves a rocket. It works by pushing “stuff” out one end of a tube at the highest possible velocity. The faster you can blow stuff out the end, the faster the tube itself is going to go.

This means rocket science is really all about how to get the exhaust gases hurling out the backside of the rocket as quickly and forcefully as possible. The fuel can be solid, like the space shuttle’s solid rocket boosters. Or the fuel can be liquid, like the shuttle’s main fuel tank filled with liquid oxygen and hydrogen.

This fuel is ignited and completely converted into exhaust gases which blast out of the rocket’s nozzles at high velocity. Really, really high velocity.

The scary part for passengers is that modern rockets are mostly made of fuel. In fact, the weight of the space shuttle’s fuel was 20 times more than the weight of the shuttle itself. Which I believe really puts a fine point on the bravery of any astronaut. Think of a rocket as a beer can, filled with explosives, that you strap yourself to the outside of. To make a rocket go faster and shorten the travel time, you want to kick material out at a higher velocity.

NASA has experimented with ion drives for some of its missions. These highly efficient engines use electric fields to accelerate particles of xenon at much higher velocities. Even though they use a fraction of the amount of fuel, ion engines can reach much higher speeds because of the high exhaust velocity.

The Vasimir experiment (Ad Astra Rocket Corporation)

And even higher velocity rockets have been tabled, such as the VASIMIR engine and even antimatter engines. So how do rockets work? Just like deflating balloons, only bigger. Much much bigger. And full of explosives and modeled on a horrible and terrifying weapon from the second world war. Really, not much like a balloon at all…

Have you ever made a rocket? What’s your favorite rocketry experiment. 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!

October 30, 2014March 1, 2017 by Fraser Cain

How Big Is The Big Dipper?

The Big Dipper is big. Come on, it’s right there in the name. But how big is the Big Dipper if you could see it from all angles?

Ask someone to name a constellation and they’ll usually say the Big Dipper. Anyone living in the Northern hemisphere who can draw a spoon generally can recognize it in the sky.

I am about to shake the foundations of your reality with a level of pedantry that at bare minimum should earn me a solid shaking and possibly even a face punch or two. The Big Dipper is not, and never will be a constellation.

It’s an asterism, a familiar pattern of stars in the sky. There are 88 constellations, and the Big Dipper isn’t one of them. It’s a part of the constellation of Ursa Major. In fact, the handle of your familiar spoon is actually the tail of the great bear.

Now that I’ve lulled you to sleep with some painfully uninteresting specifics, which you can bust out to make yourself unpopular at your AV Club pop and chip parties whenever someone refers to the “Big D” as a constellation. I strongly suggest whatever it is you tell them, you start off with *ACTUALLY….*

And now that you’ve made it this far, I shall reward you with what you’re seeking. Just how big is that Big Dipper? There are a couple of ways to skin this bear’s tail. We can say its size relative to the amount of sky real estate it occupies, or we can do the end to end Kessel run.

This chart shows the constellation of Carina (The Keel) and includes all the stars that can be seen with the unaided eye on a clear and dark night. This region of the sky includes some of the brightest star formation regions in the Milky Way. The location of the distant, but very bright and compact, open star cluster NGC 3603 is marked. This object is not spectacular in small telescopes, appearing as just a tight clump of stars surrounded by faint nebulosity. Credit: ESO — This chart shows the constellation of Carina (The Keel) and includes all the stars that can be seen with the unaided eye on a clear and dark night. Credit: ESO

You might be surprised to know how much of the sky it takes up. Astronomers measure the sky in degrees. 360 degrees takes you all the way around the sky, and our Moon measures half a degree across.

Dubhe and Merak are the pointer stars in the Big Dipper. You could put 11 full Moons side to side in the gap between them. And about 40 full Moons from bottom corner of the Dipper to the end of its handle. So, the Big Dipper measures about 20 degrees.

Here are some easy ways to measure sizes. Your pinkie nail, held at arm’s length is half a degree. 3 fingers is 5 degrees, your fist is 10 degrees. Rocking out with devil horns are 15 degrees and hang loose or the inspector gadget phone is 25 degrees.

Trekkers and Trekkies may prefer to use the Vulcan live long and prosper measurement, which is about the same number of degrees you are from getting a romantic companion.

Big Dipper Past. Credit: Alexander Meleg

So, stem to stern, how big is our giant celestial ladle? I know you know those things aren’t in anything resembling a straight line. Some of the stars are closer, and some of the stars are further out. If you could make a box that completely surrounded them, how big would it be?

The closest star in the asterism is Megrez at 58 light years. and the most distant is Dubhe at 124 light-years. And yet, they all look roughly the same brightness. This means that Dubhe is a much brighter star than Megrez, and it’s just further away. Because these stars are moving in the sky what we see as a Big Dipper today didn’t always look this way. 150,000 years ago, the Big Dipper looked like this (above).

Big Dipper Future. Credit: Alexander Meleg

And in 150,000 years from now it’ll look like this (left). Less dipper, more plow-like. Or maybe a shoe form? Shoes are kind of like ladles, right? Super gross, terribly unhygenic ladles.

Our brains keep from exploding by being pattern making machines. We see collections of stars in the sky and turn them into shapes. But it’s all just a matter of perspective. You’ve got to be right here and now to see the sky we do. Unless you’re looking for a giant “W” in which case you’ll always find one of those. It may not be the constellation Cassiopeia, but it’ll still be a pattern in the stars.

What’s your favorite asterism? Tell us in the comments below.

October 27, 2014October 17, 2016 by Fraser Cain

What Strange Places Are Habitable?

Everywhere we look on Earth, we find life. Even in the strangest corners of planet. What other places in the Universe might be habitable?

There’s life here on Earth, but what other places could there be life? This could be life that we might recognize, and maybe even life as we don’t understand it.

People always accuse me of being closed minded towards the search for life. Why do I always want there to be an energy source and liquid water? Why am I so hydrocentric? Scientists understand how life works here on Earth. Wherever we find liquid water, we find life: under glaciers, in your armpits, hydrothermal vents, in acidic water, up your nose, etc.

Water acts as a solvent, a place where atoms can be moved around and built into new structures by life forms. It makes sense to search for liquid water as it always seems to have life here. So where could we go searching for liquid water in the rest of the Universe?

Under the surface of Europa, there are deep oceans. They’re warmed by the gravitational interactions of Jupiter tidally flexing the surface of the moon. There could be life huddled around volcanic vents within its ocean. There’s a similar situation in Saturn’s Moon Enceladus, which is spewing out water ice into space; there might be vast reserves of liquid water underneath its surface. You could imagine a habitable moon orbiting a gas giant in another star system, or maybe you can just let George Lucas imagine it for you and fill it with Ewoks.

The white dwarf G29-38 (Image Credit: NASA)

Let’s look further afield. What about dying white dwarf stars? Even though their main sequence days are over, they’re still giving off a lot of energy, and will slowly cool down over the coming billions of years. Brown dwarfs could get in on this action as well. Even though they never had enough mass to ignite solar fusion, they’re still generating heat. This could provide a safe warm place for planets to harbor life.

It gets a little trickier in either of these systems. White and brown dwarfs would have very narrow habitable zones, maybe 1/100th the size of the one in our Solar System. And it might shift too quickly for life to get started or survive for very long. This is our view, what we know life to be with water as a solvent. But astrobiologists have found other liquids that might work well as solvents too.

Artist concept of Methane-Ethane lakes on Titan (Credit: Copyright 2008 Karl Kofoed). Click for larger version.

What about life forms that live in oceans of liquid methane on Titan, or creatures that use silicon or boron instead of carbon. It might just not be science fiction after all. It’s a vast Universe out there, stranger than we can imagine. Astronomers are looking for life wherever makes sense – wherever there’s liquid water. And if they don’t find any there, they’ll start looking places that don’t make sense.

What do you think? When we first find life, what will be its core building block? Silicon? Boron? or something even more exotic?

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!

October 25, 2014December 23, 2015 by Fraser Cain

You Could Fit All the Planets Between the Earth and the Moon

You could fit all the planets within the average distance to the Moon.

I ran into this intriguing infographic over on Reddit that claimed that you could fit all the planets of the Solar System within the average distance between the Earth and the Moon.

I’d honestly never heard this stat before, and it’s pretty amazing how well they tightly fit together.

But I thought it would be a good idea to doublecheck the math, just to be absolutely certain. I pulled my numbers from NASA’s Solar System Fact Sheets, and they’re a little different from the original infographic, but close enough that the comparison is still valid.

Planet	Average Diameter (km)
Mercury	4,879
Venus	12,104
Mars	6,771
Jupiter	139,822
Saturn	116,464
Uranus	50,724
Neptune	49,244
Total	380,008

The average distance from the Earth to the Moon is 384,400 km. And check it out, that leaves us with 4,392 km to spare.

So what could we do with the rest of that distance? Well, we could obviously fit Pluto into that slot. It’s around 2,300 km across. Which leaves us about 2,092 km to play with. We could fit one more dwarf planet in there (not Eris though, too big).

The amazing Wolfram-Alpha can make this calculation for you automatically: total diameter of the planets. Although, this includes the diameter of Earth too.

A nod to CapnTrip on Reddit for posting this.

October 23, 2014March 1, 2017 by Fraser Cain

Why Can’t We See the Big Bang?

Since telescopes let us look back in time, shouldn’t we be able to see all the way back to the very beginning of time itself? To the moment of the Big Bang?

You’ve probably heard that looking out into space is like looking back in time. As it takes light 1 second to get from the Moon to us. Whenever we view it, we’re seeing it 1 second in the past. The Sun is 8 light minutes away, and the light we see from it is from 8 minutes into the past.

A better example might be Andromeda, it’s 2.5 million light years away… and you guessed it, we’re seeing it 2.5 million years in the past. Since the Big Bang happened 13.7 billion years ago, using this idea, shouldn’t we be able look all the way back to the beginning of time, even if we’ve misplaced the key to our Tardis?

At the very beginning of the Universe, seconds after the Big Bang, everything was mushed together. Energy and matter were the same thing. Dogs and cats lived together. There was no difference between light and radiation, it was all just one united force.

You couldn’t see it, because light didn’t actually exist. There were no such thing as photons.

However, if you’re still insisting there’s no such thing as photons, you might want to check yourself. After these things started to separate. Photons and particles became actual things. Electromagnetism and the weak nuclear force split off and formed new bands, but could never quite get the momentum of the original lineup.

By the end of the first second, neutrons and protons were around, and they were getting mashed by the intense heat and pressure into the first elements. But you still couldn’t see that because the whole Universe was like the inside of a star. Everything was opaque. It was Scarlett Johansson hot, and too crazy to form stable atoms with electrons as we see today.

Artist's conception of Planck, a space observatory operated by the European Space Agency, and the cosmic microwave background. Credit: ESA and the Planck Collaboration - D. Ducros — Artist’s conception of Planck, a space observatory operated by the European Space Agency, and the cosmic microwave background. Credit: ESA and the Planck Collaboration – D. Ducros

After the Universe was about 380,000 years old, it had cooled down to the point that proper atoms could form. This is the moment when light could finally move, and travel distances across the Universe to you and get caught up in your light buckets. In fact, this light is known as the cosmic microwave background radiation.

So, how come we don’t see all this freed light in all directions with our eyes? It’s because the region of space where it exists is so far away, and travelling away from us so quickly. The light’s wavelengths have been stretched out to the point that light has been turned into microwaves. It’s only with sensitive radio telescopes and space missions that astronomers can even detect it.

Unfortunately, we’ll never be able to see the Big Bang. Even though we’re looking back in time, right to the edge of the observable Universe, it’s just beyond our reach. If you could look at the Universe at any point in time, what would it be? 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!

October 20, 2014December 23, 2015 by Brian Koberlein

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.

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!

October 16, 2014March 1, 2017 by Fraser Cain

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!

October 13, 2014March 1, 2017 by Fraser Cain

What Does Earth Look Like From the Moon?

If you could stand on the Moon and look back at the Earth, what would you see? How would it compare from our familiar vantage point?

We know what the Moon looks like from Earth, but what would the Earth look like from the Moon?

Pretty strange, actually.

The Moon is tidally locked to us, and it presents only one face to the Earth.

If you were on the near side of the Moon, the Earth would always be in the sky. And if you were on the far side, you’d never see it.

Also, it’s weird there. So you’d probably want to move.

If you were standing on the Moon, looking up, you’d see the Earth, hanging in the sky forever, or for however long your robot body holds out.

It would go through phases, like the Moon, moving from total darkness, though quarter illumination, Full Earth, and back again. But the features on the Earth would be changing. The face of the Earth would be illuminated, and you’d see the entire planet turning throughout the day and you could use it to cheat on Geography tests.

It wouldn’t be totally dark on the night side because “humans”. You’d see those beautiful blobs of stringy light on the shadowed parts of the Earth.

Our Moon follows an elliptical path around the Earth, getting as close as 363,000 km and as far as 405,000 km.

This means the Earth would get bigger and smaller in the sky. As Earth is much larger than the Moon, it would take up 13 times as much area.

The Earth wouldn’t actually hang motionless in the sky. We see lunar libration from our perspective, which lets us peek around the corner of the Moon. But from the Moon, we’d see the Earth move back and forth in the sky over 27 days.

Remember this famous Earthrise photo captured by Apollo 8? It’s on every single sales brochure for lunar real estate.

Don’t be fooled, if you were on the Moon, you’d never see an Earthrise like that.
In fact, the only way to get a view like that is be on a spacecraft orbiting the Moon.

If I lived on the Moon, I’d want property Earthside.

Would you like to see the Earth from the Moon? What other views of the Solar System would you like to get?

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!

October 10, 2014March 1, 2017 by Fraser Cain

What Part of the Milky Way Can We See?

When you look up and see the Milky Way, you’re gazing into the heart of our home galaxy. What, exactly, are we looking at?

Anyone who’s ever been in truly dark skies has seen the Milky Way. The bright band across the sky is unmistakable. It’s a view of our home galaxy from within.

As you stare out into the skies and see that splash of stars, have you ever wondered, what are you looking at? Which parts are towards the inside of the galaxy and which parts are looking out? Where’s that supermassive black hole you’ve heard so much about?

In order to see the Milky Way at all, you need seriously dark skies, away from the light polluted city. As the skies darken, the Milky Way will appear as a hazy fog across the sky.

Imagine it as this vast disk of stars, with the Sun embedded right in it, about 27,000 light-years from the core. We’re seeing the galaxy edge on, from the inside, and so we see the galactic disk as a band that forms a complete circle around the sky.

Which parts you can see depend on your location on Earth and the time of year, but you can always see some part of the disk.

The galactic core of the Milky Way is located in the constellation Sagittarius, which is located to the South of me in Canada, and only really visible during the Summer. In really faint skies, the Milky Way is clearly thicker and brighter in that region.

Want to know the exact point of the galactic core? It’s right… there.

During the Winter, we’re looking away from the galactic core to the outer regions of the galaxy. It still has the same band of stars, but it’s thinner and without the darker clouds of dust that obscure our view to the galactic core.

How do astronomers even know that we’re in a spiral galaxy anyway?

There are two major types of galaxies, spiral galaxies and elliptical galaxies.

Elliptical galaxies are made up of so many galactic collisions, they’re nothing more than vast balls of trillions of stars, with no structure. Because we can see a distinct band in the sky, we know we’re in some kind of spiral.

The differences between elliptical and spiral galaxies is easy to see. M87 at left and M74, both photographed with the Hubble Space Telescope. Credit: NASA/ESA

Astronomers map the arms by looking at the distribution of gas, which pulls together in star forming spiral arms. They can tell how far the major arms are from the Sun and in which direction.

The trick is that half the Milky Way is obscured by gas and dust. So we don’t really know what structures are on the other side of the galactic disk. With more powerful infrared telescopes, we’ll eventually be able to see though the gas and dust and map out all the spiral arms.

If you’ve never seen the Milky Way with your own eyes, you need to. Get far enough away from city lights to truly see the galaxy you live in.

The best resource is “The Dark Sky Finder”, we’ll put a link in the show notes.

Have you ever seen the Milky Way? If not, why not? Let’s hear a story of a time you finally saw 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!

September 5, 2014December 23, 2015 by Brian Koberlein

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.