Horizon: How Big Is the Universe? (T) Mon 21:00

santaman2000

M.A.B (Mad About Bushcraft)
Jan 15, 2011
16,909
1,120
68
Florida
Scientists say matter is made up of protons, neutrons and electrons. They seem to always neglect to mention the vastly more prolific morons.
 

Teepee

Bushcrafter (boy, I've got a lot to say!)
Jan 15, 2010
4,115
5
Northamptonshire
True enough. But not neccessarily a measureable amount and for the context of my post "none" is accurate enough.

Even with our limited veiw of the stars, I don't believe it is accurate enough. The temp is taken to be just under 3 kelvin and lone Hydrogen atoms permeate space everywhere.

Add to that 75% of the mass of the universe is still missing (dark matter), 'none' just may be a very long way off. :)
 

santaman2000

M.A.B (Mad About Bushcraft)
Jan 15, 2011
16,909
1,120
68
Florida
So a vacuum is devoid of matter & heat except when it ain't ...................Sounds logical to me:D

LOL. Think of it as analogous to the glass with only a bit of water in the bottom. The water represents the matter and energy. It's there, but only in a small bit of space at the bottom of the glass; the rest of the glass is empty. Likewise matter and energy only occupy a small part of space (held in close proximatey to other matter by gravity) while the rest of space (the very vast proportion of space) is empty (and a vacuum)
 

santaman2000

M.A.B (Mad About Bushcraft)
Jan 15, 2011
16,909
1,120
68
Florida
Even with our limited veiw of the stars, I don't believe it is accurate enough. The temp is taken to be just under 3 kelvin and lone Hydrogen atoms permeate space everywhere.

Add to that 75% of the mass of the universe is still missing (dark matter), 'none' just may be a very long way off. :)

Perhaps. But that's not quite the way I was taught it. I say not quite because my professors would not have used the word "permeates." A presence, yes. Permeates, no. For practical discussion, a vacuum devoid of heat or other energy.
 

mountainm

Bushcrafter through and through
Jan 12, 2011
9,990
12
Selby
www.mikemountain.co.uk
LOL. Think of it as analogous to the glass with only a bit of water in the bottom. The water represents the matter and energy. It's there, but only in a small bit of space at the bottom of the glass; the rest of the glass is empty. Likewise matter and energy only occupy a small part of space (held in close proximatey to other matter by gravity) while the rest of space (the very vast proportion of space) is empty (and a vacuum)

Photons exist in (ie. pass through) a vacuum, as do other wavelengths of energy (infra red, radio, microwave) etc. A vacuum certainly isn't devoid of everything.
 

santaman2000

M.A.B (Mad About Bushcraft)
Jan 15, 2011
16,909
1,120
68
Florida
Photons exist in (ie. pass through) a vacuum, as do other wavelengths of energy (infra red, radio, microwave) etc. A vacuum certainly isn't devoid of everything.

No. It isn't. But they dissapate as they do and the amount becomes miniscule once they travel light years away from the source. And as the whole of space (extremely vast) compared to that space occupied by matter and energy in the form of galaxies and solar sytems within those galaxies (extremly miniscule by comparison), for practical discussion, the comparison stands.
 

mountainm

Bushcrafter through and through
Jan 12, 2011
9,990
12
Selby
www.mikemountain.co.uk
No. It isn't. But they dissapate as they do and the amount becomes miniscule once they travel light years away from the source. And as the whole of space (extremely vast) compared to that space occupied by matter and energy in the form of galaxies and solar sytems within those galaxies (extremly miniscule by comparison), for practical discussion, the comparison stands.

It isn't empty though - it has dimensions, time, it can be defined, measured. We know it is there - this vacuum. It is detectable.
 
Feb 15, 2011
3,860
2
Elsewhere
The spacial vacuum beyond the Earth's atmosphere certainly isn't void of matter, It's full of freakin' satellites & other bits of orbiting junk.....................aliens shouldn't have any trouble finding us......turn left at Mars & follow the garbage trail :D
 

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