Science facts that amaze you?

Maximus Alexander

sbsquarepants wrote: »

The gravitational pull of the sun on the oceans is roughly 50% that of the moon afaik. I'm open to correction on the exact number but it's definitely less, not more and certainly not 175 times more. Every time you double the distance between 2 objects, you quarter the gravitational attraction (the inverse square rule - g is proportional to 1/distance squared)

The force exerted on the Earth by the Sun's gravity is indeed 175 times that of the moon. However, the difference in the effect of the Sun's gravitational field across the Earth is negligible, because the Earth's size is so tiny compared to the Sun's distance.

The difference in the Moon's gravitational field across the Earth's surface is greater, because Earth's size is much bigger as a fraction of the distance to the moon. So, the Moon's gravity has a greater effect on the parts of the Earth that are closer to it than those that are off to the sides, raising tides.

Egginacup

thelad95 wrote: »

The population of County Leitrim would not fill Croke Park. Science bitches!!!!!

The entire population of ants in the world is heavier than the entire population of humans.

And to add to that, to illustrate how many insect there are on the planet, 99% of all living creatures can fly.

Egginacup

glass is not actually a solid but a super slow moving liquid.

The Dagda

Egginacup wrote: »

glass is not actually a solid but a super slow moving liquid.

Myth.

Gazzmonkey

The Dagda wrote: »

Myth.

Look at the glass panes in extremely old buildings, the bottom of every surviving pane is thicker than than the top.

The glass flowed downward slightly due to gravity.

Maximus Alexander

Gazzmonkey wrote: »

Look at the glass panes in extremely old buildings, the bottom of every surviving pane is thicker than than the top.

The glass flowed downward slightly due to gravity.

Look at the moon. It's an oblate spheroid, wider at the along the equator than between the poles due to its rotation. It's not a liquid though.

Also, the glass is thicker at the bottom in old buildings because they used to be really bad at making glass.

gerard_65

The sun is white not yellow.
There is no dark side of the moon.

Maximus Alexander

gerard_65 wrote: »

There is no dark side of the moon.

Uhh... Yes there is. :eek:

MonkieSocks

gerard_65 wrote: »

There is no dark side of the moon.

Thats gonna keep me awake all night now.....thanks :mad:

bnt

Maximus Alexander wrote: »

Uhh... Yes there is. :eek:

There is always a dark side at any given time, but it's not always the side known as "the Dark Side of the Moon". Sometimes the "Dark Side" gets all the light. :P

GLaDOS

gerard_65 wrote: »

There is no dark side of the moon.

As a matter of fact it's all dark

Maximus Alexander

bnt wrote: »

There is always a dark side at any given time, but it's not always the side known as "the Dark Side of the Moon". Sometimes the "Dark Side" gets all the light. :P

Yeah I don't follow... The side that faces away from the sun at any given time is dark. Is it a thing that people think this is not the case?? You can literally see it during any phase of the moon apart from when it's full.

Capt'n Midnight

Maximus Alexander wrote: »

Uhh... Yes there is. :eek:

"there is no dark side in the moon, really. As a matter of fact it's all dark"
Gerry O'Driscoll



The albedo of the Moon is around 0.12 , so it's nearly as dark as coal.

srsly78

Gazzmonkey wrote: »

Look at the glass panes in extremely old buildings, the bottom of every surviving pane is thicker than than the top.

The glass flowed downward slightly due to gravity.

As you were told already, it's a myth. Google it.

Some old windows are thicker at the bottom because of the manufacturing process. It does flow when molten, like many other solids. Those old windows were like that when they were brand new.

catallus

God damn it.

Technically glass does "flow" but it flows at about 1mm per 1 million years. It has nothing to do with the shape of old panes of glass, which is, as has been pointed out, due to the processes used to make panes in the past.

The "dark side of the moon" isn't actually dark, it gets plenty of light. But the phrase "dark side of the moon" refers to that side of the moon which always faces away from the earth; this effect is called tidal locking and is a property of satellites which rotate around each other.

Maximus Alexander

Capt'n Midnight wrote: »

"there is no dark side in the moon, really. As a matter of fact it's all dark"
Gerry O'Driscoll



The albedo of the Moon is around 0.12 , so it's nearly as dark as coal.

The albedo of a rainforest is 0.07 - 0.15. I wouldn't call them "as dark as coal" though.

sbsquarepants

Capt'n Midnight wrote: »

"there is no dark side in the moon, really. As a matter of fact it's all dark"
Gerry O'Driscoll



The albedo of the Moon is around 0.12 , so it's nearly as dark as coal.

Maximus Alexander wrote: »

The albedo of a rainforest is 0.07 - 0.15. I wouldn't call them "as dark as coal" though.

Today, I have learned a new word!

I'm not quite sure I understand it though. At the risk of sounding like an idiot - if albedo means overall reflectiveness (usually of a specific frequency but in these cases averaged across the visible spectrum) I'm figuring the rainforest is so low because it's basically absorbing all frequencies bar green, but I don't understand how the moon is so low when it appears so bright, light grey at least, touching on off white sometimes, surely to appear white you must reflect all frequencies? Fresh snow has an albedo of .9 for example. I'm puzzled.
I always looked on it as perfectly white = reflects everything, perfectly black = reflects nothing and shades of grey are in between, the closer to white or black the grey is the more or less frequencies reflected. But now I have my doubts, does a particular shade of grey equate to a specific frequency? This albedo lark would seem to suggest it does.

Maximus Alexander

sbsquarepants wrote: »

Today, I have learned a new word!

I'm not quite sure I understand it though. At the risk of sounding like an idiot - if albedo means overall reflectiveness (usually of a specific frequency but in these cases averaged across the visible spectrum) I'm figuring the rainforest is so low because it's basically absorbing all frequencies bar green, but I don't understand how the moon is so low when it appears so bright, light grey at least, touching on off white sometimes, surely to appear white you must reflect all frequencies? Fresh snow has an albedo of .9 for example. I'm puzzled.
I always looked on it as perfectly white = reflects everything, perfectly black = reflects nothing and shades of grey are in between, the closer to white or black the grey is the more or less frequencies reflected. But now I have my doubts.

Albedo is a complicated thing, in fact there is more than one type of albedo that will give different values for the same object. Some objects are highly directional and things like shadow hiding will also have an effect. There are also things like opposition surge which increase brightness when the light source is behind the observer.

Interestingly, rainforests actually do appear black (or very dark at least) from orbit because, as you say, they absorb so much light and reflect so little.

Different parts of the surface of the moon have wildly different albedo, but it averages out at about 0.12. The Earth is in around 0.3 if I remember correctly.

Capt'n Midnight

Also you have to remember that reflection is not like a mirror, the reflected light is dispersed in all directions.

Brightest sunlight is 120,000 lux
Full moon on a clear night is 0.25 lux

Moonlight from a quarter moon at 0.01 lux is 12 million times darker than the sun

sbsquarepants

Thanks folks. That's a bit clearer now. My grasp is still a little shaky mind, but i'll read up on it a bit when I get a chance, I'd never heard the word before today.
Every day is a school day!:)

Maximus Alexander

sbsquarepants wrote: »

but I don't understand how the moon is so low when it appears so bright, light grey at least, touching on off white sometimes, surely to appear white you must reflect all frequencies? Fresh snow has an albedo of .9 for example. I'm puzzled.

In thinking about this further, I suspect the moon appears so bright and white to us because of the way our eye (or brain) works. As in it looks super bright because it's against a dark, black backdrop. I suspect if you could put Enceladus in orbit and look at it and the moon side-by-side, the moon would look like a dark grey by comparison. This is just guesswork on my part though.

allibastor

Science facts that amaze me.

That all information available to us shows that if we make computers which are smarter than us and can think for themselves they will see us a threat/consumer of resources. Any technology which unnaturally prolongs life yet doesn't add to the natural resources available.

All other advances which will limit the human potential for growth and will outdate what we can do.

Yet science still moves towards this as a goal.
Not a terminator rant, but there is no other species on the planet which has such over population and consumes as much as humans, save for a virus.

sbsquarepants

allibastor wrote: »

Yet science still moves towards this as a goal.
Not a terminator rant, but there is no other species on the planet which has such over population and consumes as much as humans, save for a virus.

Slightly off topic but this is not really true.
What we have is a distribution problem caused by greed, hatred and apathy. Half the world is obese, the other half is starving - we have all the resources we need for ourselves and probably for billions of others - we are just a species of assholes generally speaking. We have all these lofty ideals about fraternity and social responsibility that we just point blank fail to live up to. We are a lot more selfish and individualistic than our sanctimonious bullshít would have you believe.

endacl

Maximus Alexander wrote: »

In thinking about this further, I suspect the moon appears so bright and white to us because of the way our eye (or brain) works. As in it looks super bright because it's against a dark, black backdrop. I suspect if you could put Enceladus in orbit and look at it and the moon side-by-side, the moon would look like a dark grey by comparison. This is just guesswork on my part though.

The darkest object in the solar system is the sun.

sbsquarepants

endacl wrote: »

The darkest object in the solar system is the sun.

The newspaper?

How the hell could the sun, that big bright fussion reactor you can see and feel from millions of miles away be darker than the earth for example?

endacl

sbsquarepants wrote: »

The newspaper?

How the hell could the sun, that big bright fussion reactor you can see and feel from millions of miles away be darker than the earth for example?

Linkydink

srsly78

Probably some lame definition of the term dark, because the sun absorbs all the light that hits it - rather than reflecting it. Thus it may be the darkest, but it's also the most luminous, go figure.

Capt'n Midnight

allibastor wrote: »

Science facts that amaze me.

That all information available to us shows that if we make computers which are smarter than us and can think for themselves they will see us a threat/consumer of resources. Any technology which unnaturally prolongs life yet doesn't add to the natural resources available.

Then again our civilisation is powered by a tiny fraction of a quarter of a billionth of the Suns light

Lots of room for expansion to the asteroids and the Oort cloud

the area of large asteroids is fairly small
https://xkcd.com/1389/
but you could use them to make space stations and stuff with far larger areas.

also most of the platinum group metals on earth came from Asteroids
and comets are full of stuff for life like water and carbon and nitrogen


also exoplanets https://xkcd.com/1298/ https://xkcd.com/1071/

endacl

srsly78 wrote: »

Probably some lame definition of the term dark, because the sun absorbs all the light that hits it - rather than reflecting it. Thus it may be the darkest, but it's also the most luminous, go figure.

Not really. More a play on our limited perception of 'bright'. In the grand scheme of things...

allibastor

sbsquarepants wrote: »

Slightly off topic but this is not really true.
What we have is a distribution problem caused by greed, hatred and apathy. Half the world is obese, the other half is starving - we have all the resources we need for ourselves and probably for billions of others - we are just a species of assholes generally speaking. We have all these lofty ideals about fraternity and social responsibility that we just point blank fail to live up to. We are a lot more selfish and individualistic than our sanctimonious bullshít would have you believe.

August 19 is Earth Overshoot Day 2014, marking the date when humanity has exhausted nature’s budget for the year. For the rest of the year, we will maintain our ecological deficit by drawing down local resource stocks and accumulating carbon dioxide in the atmosphere. We will be operating in overshoot.
Just as a bank statement tracks income against expenditures, Global Footprint Network measures humanity’s demand for and supply of natural resources and ecological services. And the data is sobering. Global Footprint Network estimates that approximately every eight months, we demand more renewable resources and C02 sequestration than what the planet can provide for an entire year.

No, that means in terms of food. And yes, people are assholes.

The science fact that amazes me is that people can see an answer in front of them but still not understand it