Strange and Interesting Facts

[Charlie]

I love strange and interesting facts so if you have any, post them here. Here's a few I like:

Light is invisible. Bear this in mind next time you're watching Star Wars or any other movie that shows laser beams in outer space. It's bull****. You can never see light, you can only see the object(s) light reflects off.

We never really touch anything. Grab a hot coal, stroke a cat, cut off your finger with an axe, you've not really come into contact with any of those objects. What you feel is electrons in the outer shells of atoms repelling each other at 10^-8 metres. Right now you aren't sitting on a chair, you're hovering slightly above it.

There are over 100 trillion connections in the brain. Not much more to say about that other than it's an amazing figure and gives hope that maybe one day we can evolve into semi-intelligent apes.

Buddhists desire to have no desires. That may not seem interesting until you realise it's a paradox.

* caveat: I don't really believe in facts and regard nothing as absolute. To me, facts are merely what our senses and instruments that we built using our senses are capable of telling us what seems to be happening. But that would have been too long and too ugly a thread title.

[Dogg Thang]

I'm pretty sure I am sitting on this chair.

[eastyy]

check vsauce on youtube

think they mention something about you are not actually seeing the colour yellow on your monitor

[Charlie]

Nice one, eastyy. An entire video library of geeky facts for me to discover.

[eastyy]

you may spend the next few hours on it .....i did

[Brad]

I'm pretty sure I am sitting on this chair.

If you grab the sides of the chair and pull your bum into the seat really hard THEN you're sitting in the chair.

[fishbowlhead]

Bees like caffeine, its given off in the pollen of flowers to entice them to come back.

Caffeine is an natural insecticide, its actually poisonous to almost all insects, however bees can handle small doses of it, just enough for a benefit to them. Try putting your used coffee granules around the garden to keep nasty pests off your flowers.

[Charlie]

I'm gonna try that. But if I find a load of dead bees in my garden I'll be upset.

[charlesr]

If you reach the speed of light you also become infinitely dense. Although I think many of us achieve that daily without the help of light speed.

Assuming you can ride a bike, if someone gave you a bike with stabilisers on, you'd completely fail to remember how to use it and probably fall off, as demonstrated by my son (OMGnotthisagainshutupcharles).

Little lambs eat ivy.

[QualityChimp]

If you reach the speed of light you also become infinitely dense.

What happens if you're in a spaceship travelling at the speed of light and you turn the headlights on?

[EJG1980]

What happens if you're in a spaceship travelling at the speed of light and you turn the headlights on?

ASK A PHYSICIST
BY DR. DAVE GOLDBERG APR 29, 2010 12:46 PM

What Happens If You’re Traveling At The Speed Of Light And Turn On Your Headlights?

One of the most popular questions from our "ask a physicist" feature was, "What happens if you're driving at the speed of light and you turn on your headlights?" The simple answer: You can't. So quit trying.

At least ten of you asked some variant of this question, but Turael asked it first and arguably most succinctly. So Turael, feel free to email me so we can send you a free copy of A User's Guide to the Universe.

Sadly, physics teaches that we are forever confined to sub-light speeds.

There were several comments, in response to the original call for questions, that took umbrage at this certainty on the part of physicists. Are we just being closed-minded? There are always people who are skeptical of equations, regardless of other evidence. For example, long after the advent of nuclear weapons and power have vindicated Einstein, I still get detailed manuscripts from people every few weeks claiming that E=mc2 is wrong.

So no lengthy derivations, but I will give you a few observations, and hopefully that will be enough. Special relativity predicts that if you take a massive particle and keep applying forces on it, it goes faster and faster, slowly approaching the speed of light, but never quite reaching it. Right now, for example, the Large Hadron Collider has protons flying around it at a whopping 3.5 TeV. This means that the protons are traveling 99.999994% the speed of light, and when the LHC gets up to full power (at about twice the energy), the protons will go even faster, but even then, less than the speed of light. At these speeds, the difference between "at" and "a tiny bit below" the speed of light may seem academic, but it makes a world of difference.

We always need to accept the possibility that we could be wrong, but in this case, there's just so much evidence that we're right! The particle colliders wouldn't actually work if relativity were wrong. For that matter, neither would GPS devices. Michelson and Morley found in 1887 that light travels at the same speed to all moving observers, a result that doesn't make sense unless special relativity is correct. All of modern physics (and technology) is built on an edifice of special relativity, and so far, it's proven ridiculously accurate. In other words, you've got a very big barrier to overcome if you want to prove Einstein wrong.

Part of the reason that people are so confused about this aspect of relativity is that it flies in the face of everyday experience. If I'm in a boxcar moving 60 mph and throw a 90 mph fastball, someone standing by the side of the tracks will see the ball moving at 150 mph. It seems like the same logic should work with light. Except that it doesn't.

Strange things happen when you get close to the speed of light, and they become stranger still when you realize that your high school physics teachers (perhaps inadvertently) lied to you. Lots of you are sci-fi nerds, so I'm guessing that at least once in your lives you learned Newton's force equation, F=ma. Deciphering the symbols, it means that if you apply a constant force to a particle, it should experience a constant acceleration. Taken to its natural extremes, if I apply a force for long enough and the particle keeps accelerating, eventually it should exceed the speed of light. Voila! Newton's force equation (at least in the form it's normally written) is wrong.

But then what happens when you get close to the speed of light and turn on your headlights? From your perspective: nothing, or at least nothing special. If you held a mirror in front of you, you'd look exactly as you always have. In fact, one of the surprising things about special relativity is that if you weren't looking at all of the scenery passing you, you couldn't tell that you are moving at all.

But from the perspective of people standing on the sidelines, things look really cool. Stationary observers would notice that your entire ship (or racecar, or whatever you're driving at 99% the speed of light) is compressed along your direction of motion. If you're standing the right way, it'll look like you've lost weight and that your body has been flattened under a giant stone.

They'd also see your clocks – and your heartbeat, your speech, your computer cycles – running slow. This is true, but completely unobservable in everyday life. Typically on earth, it's an effect of about 1 part in a quadrillion, but at 99% the speed of light, you'll appear to be running at only 1/7th speed. The length contraction and time dilation conspire (out of mathematical necessity) to make your high beams move at the speed of light to somebody watching you from the side. But just as a baseball gets a boost of energy when you throw it on a train (which you shouldn't do, incidentally) the light gets a boost of energy as well. The difference is that it doesn't go faster; it just looks bluer. In this case, your headlights would be boosted into the ultraviolet.

Stranger still is the case of two spaceships traveling toward one another, each a 99% the speed of light. Common sense would dictate that the captain of each ship should see the other hurtling toward him at faster than light. Not so! One of the results of the constant speed of light is that all relative speeds are going to be less than you think. In this case, for example, each captain would see the other coming at him at only 99.995% the speed of light.

Back to the original question (which, incidentally, is so startlingly good that it's one of the ones that Einstein himself asked as a young man), what would happen if you could get up to the speed of light? As you get closer and closer to the speed of light, time gets slower and slower compared to stationary observers. So if you really need an answer to the original question, this means that if you actually hit the speed of light for real, time would stop entirely, which means that nothing could happen. But that's okay, because you can't get up to the first place.

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Physics facts are always strange, always interesting, and almost always impossible to wrap your head around!

[kryss]

In set theory, if A={1,2,3} and B={4,5,6} then A-B={1,2,3}.

FACT.

[Darwock]

I love strange and interesting facts so if you have any, post them here. Here's a few I like:

Light is invisible. Bear this in mind next time you're watching Star Wars or any other movie that shows laser beams in outer space. It's bull****. You can never see light, you can only see the object(s) light reflects off.

I'm no expert, but they aren't firing 'light' guns, they are firing laser guns, and LASER is 'light amplified by stimulated emission of radiation' or something like that, so it's not just light. Besides, we already have laser beams and they are visible. So stop trying to be clever.

[kryss]

We only see laser beams as the light is reflected off particles in the air so sadly he's right in that respect.
However, they're not lasers in Star Wars but "blasters" so he's also not right at the same time. Just like in Star Trek they're "phasers".

[Adam]

There are no land snakes in New Zealand. It’s part of New Zealand’s bio security to keep all snakes out and if a person is aware of a snake, by law it must be reported.

Giraffes can go without water longer than a camel.

Twelve people have walked on the moon

Almonds are members of the rose flower family or rosaceae family. The peach is also a member of the rose family.

The tallest girl in the world ever recorded was 8 feet 2 inches tall and died at the young age of 17.

Squirrels forget where about 50% of the nuts they’ve hidden are.

If the human stomach doesn’t produce a new layer of mucus every two weeks it will totally digest itself.

The price of the Titanic cost about $7 million to build and the price of the Titanic movie was about $200 million to make.

The eye of an ostrich is larger than it’s brain.

Snails can sleep for up to 3 years.

You cannot think of an English word to rhyme with the word month because there isn’t one.

I copied these from another site.