Name one or more favorite scientific facts!

kellyb

Penultimate Amazing
kellyb
Joined
Jan 18, 2006
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I'll start. :)

The stars you see in the sky at night are snapshots of the distant past, and the stars themselves could be long dead.
 
kellyb said:
The stars you see in the sky at night are snapshots of the distant past, and the stars themselves could be long dead.
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Er, um, not really. Most visible stars are within 200 light years. The furthest is about 16K light years. And it's not terribly likely any of the stars we can see is actually dead now. Betelgeuse is one of the few visible stars expected to explode "soon" but soon in this context is thought to be something like a million years. At 640 light years away that gives about 1 in 2,000 chance that it has already gone supernova.

ETA: https://imgs.xkcd.com/comics/ancient_stars.png

ETA: The one major galaxy we can see is a couple million years old.
 
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Angle of incidence equals angle of reflection.

Useful in photography, billiards, racquetball, jai-alai, marbles, light waves, sound waves, radio waves, too much to count.
 
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When you turn your heater on in Winter you are not trying to get more hot, but trying to cool down at a more comfortable rate.


Norm
 
alfaniner said:
Angle of incidence equals angle of reflection.

Useful in photography, billiards, racquetball, jai-alai, marbles, light waves, sound waves, radio waves, too much to count.
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To continue in RecoveringYuppy's vein, things people consider to be scientic facts sometimes aren't.

This e.g. is definitely not true in the case of ball games like the four you mentioned, except as a rough first order approximation. It neglects the rotational momentum of the balls.
 
The non-existence of the intra-mercurial planet "Vulcan", a planet, first proposed over 100 years ago, in order to try to explain the errors in Mercury's precession measurements...

Turns out that Mercury's precession errors are caused by the massive gravity well of the Sun due to General relativistic effects. This is beautifully explained for the layman in this short missive by Isaac Asimov - an oldie but a goodie

http://geobeck.tripod.com/frontier/planet.htm
 
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If you were to disassemble a man into his constituent atoms and then weigh those atoms, they would be about the same weight as the man. But if you disassembled the atoms into protons, neutrons and electrons and weighed each of those, they would only weigh about 5% of the guy.
 
Loss Leader said:
If you were to disassemble a man into his constituent atoms and then weigh those atoms, they would be about the same weight as the man. But if you disassembled the atoms into protons, neutrons and electrons and weighed each of those, they would only weigh about 5% of the guy.
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How does that work?
 
- About 1% of the static you saw when not tuned to channel on an old analog television set was background radiation from the Big Bang.
 
Loss Leader said:
Beats the hell out of me. The energy holding the particles together is somehow also mass.

I got it from a book about questions science has yet to answer.
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Oh, cool!

eta:
Do you remember the name of the book?
 
You have been alive for more than 4.5 billion years, sort of.


Literally every living cell in your body has been functioning continuously for all that time.
 
Cheetah said:
You have been alive for more than 4.5 billion years, sort of.


Literally every living cell in your body has been functioning continuously for all that time.
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Along the same lines I remember a QI episode that said your entire bodies cells are renewed every 7 years (might be out with the number slightly)

So in effect everyone over 7 is 7 years old
 
There were many facts in 'Living With The Stars' by Karel and Iris Schrijver - far too many to remember - but there was one about thousands of C4 atoms in each of our cels every second breaking down into something else, nitrogen iirc. Sorry to be a bit vague! :)
 
The Great Zaganza said:
The biomass of all humans is roughly equal to the biomass of all ants.
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That is cool tbf

Presumably with ants being so strong, that if every human sat together on every ant together the ants could all carry us to the pub.

Would need to be a big pub though.......Actually we could get all the ants to build the worlds biggest anthill and the humans could fashion it into massive pub.

Coasters and glasses might be an issue, but we could get the ants to collect nuts and other finger food
 
Cheetah said:
You have been alive for more than 4.5 billion years, sort of.


Literally every living cell in your body has been functioning continuously for all that time.
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I don't think this is true. Cells die all the time and are replaced by new ones.

You might be thinking of the fact that every atom in our bodies was formed billions of years ago inside stars (one of my favourite facts).
 
smartcooky said:
The non-existence of the intra-mercurial planet "Vulcan", a planet, first proposed over 100 years ago, in order to try to explain the errors in Mercury's precession measurements...

Turns out that Mercury's precession errors are caused by the massive gravity well of the Sun due to General relativistic effects. This is beautifully explained for the layman in this short missive by Isaac Asimov - an oldie but a goodie

http://geobeck.tripod.com/frontier/planet.htm
Click to expand...


Just quoting the (most) important bit for anyone that doesn't want to read the entire (fantastic) article.

By Einstein's relativistic view of the Universe, mass and energy are equivalent, with a small quantity of mass equal to a large quantity of energy in accordance with the equation e=mc2.

The Sun's enormous gravitational field represents a large quantity of energy and this is equivalent to a certain, much smaller, quantity of mass. Since all mass gives rise to a gravitational held, the Sun's gravitational held, when viewed as mass, must give rise to a much smaller gravitational field of its own.
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Brainache said:
I don't think this is true. Cells die all the time and are replaced by new ones.

You might be thinking of the fact that every atom in our bodies was formed billions of years ago inside stars (one of my favourite facts).
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Yep, one of my favourites too;

"a small proportion of the the atoms in your gold wedding ring/engagement ring/necklace/whatever were formed the the fires of supernovae, but the majority those atoms come from an even more spectacular event, the collision of two neutron stars."
 
Cheetah said:
You have been alive for more than 4.5 billion years, sort of.


Literally every living cell in your body has been functioning continuously for all that time.
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What am I missing here? Did you mean "every atom" and not "every living cell"?



ETA: ninja'd
 
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Brainache said:
I don't think this is true. Cells die all the time and are replaced by new ones.

You might be thinking of the fact that every atom in our bodies was formed billions of years ago inside stars (one of my favourite facts).
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Nope, cells simply divide: there is no 'replacement'. 'New ones' are just halves of old ones. The old ones were, themselves, just parts of older ones, all the way back...
 
Not so much a specific fact but the way some things in the math keep turning up like pi, e and sequences like the Fibonacci series or sines and cosines or how often parabolas turn up. It's impressive to me how universal some of these things are.
 
TheGnome said:
To continue in RecoveringYuppy's vein, things people consider to be scientic facts sometimes aren't.

This e.g. is definitely not true in the case of ball games like the four you mentioned, except as a rough first order approximation. It neglects the rotational momentum of the balls.
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It's not true for photons (i.e. light), either. A photon impacting a mirror is absorbed and another emitted at a random angle. It's only when multiple photons are involved that the wave phases interfere and the probable trajectory of the beam matches the quoted rule.
 
JoeMorgue said:
- About 1% of the static you saw when not tuned to channel on an old analog television set was background radiation from the Big Bang.
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Would you have a link or something to support this? Just offhand I plain don't believe this.

Most of what you call static is thermal noise generated in the receiver. Very little is picked up by the antenna as you could see when you disconnected it.

Also I think there is only little background radiation from the Big Bang in the VHF and UHF range (up to about 1 GHz) that could be picked up by a TV receiver.

I would be quite interested if you could prove me wrong. That would be one more thing I didn't get.
 
TheGnome said:
To continue in RecoveringYuppy's vein, things people consider to be scientic facts sometimes aren't.

This e.g. is definitely not true in the case of ball games like the four you mentioned, except as a rough first order approximation. It neglects the rotational momentum of the balls.
Click to expand...

baron said:
It's not true for photons (i.e. light), either. A photon impacting a mirror is absorbed and another emitted at a random angle. It's only when multiple photons are involved that the wave phases interfere and the probable trajectory of the beam matches the quoted rule.
Click to expand...

Oh, for fact's sake...
 
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