Stephen Hawking's Universe - EP4: On The Dark Side (5/ 5)

[murtadalion]

If dark matter exists why doesn't it come in contact with the normal matter that we see today.....they must collide right...?

[MrDBarch]

Could it be that all the items in the universe, ie all the matter, are moving apart at a constant rate, but that items closer to us appear to be moving faster, and items further away appear to be moving slower?

[thickblkpa]

Great to see a woman so knowledgeable about the universe. It's a shame that most societies want to suppress their value in the world.

[zukodude487987]

Could it be that the big bang is nothing more than a super nova of some super-sized star?

[karkovice10]

"I was asked not to talk about the end of the universe in case it depressed the stock market..." LOL.

[muzammilali007]

Lol this cosmic crunch reminded me of a religious person who was trying to convince people by telling them this might be how the judgment day would happen. I just makes me laugh at the stupidity of these people, they think the entire universe is a part of some grand design and there couldn't possibly be any other intelligent beings in the entire cosmos.

[grendel1980]

50-100 billion years from now eh? Guess I have time to wait...

[wildsabes]

liquid nitrogen: the melting point of S is -346 F;

so he probably does mean Fahrenheit, but the atoms shouldn't be completely put to a halt, because the photons have to be 'refelected'

[AbdulMumit]

"At over 300 degrees below zero the very atom are stilled"? :D If he means Celsius... it's false. If he means Kelvins, it's even more false. And if Fahrenheits, -300 is not low enough to stop atoms. :)

[masterXVI]

over 300 degrees below 0? wtf?

[Zryuken]

wtf?

[coturnix19]

Fahrenheit ?

[sssorry]

@masterXVI He may be referring to the Fahrenheit scale; liquid nitrogen freezes at -346 °F and boils at -320 °F

[forza599]

I love his smile when he's talking about the stock market, what a crazy thing to think about! Hahaha human beings are so ridiculous.

PS wonderful series thanks for the post.

[AFHound]

scientists don't even know the dark matter how hell they want to the density and other stuffs?

scientists just jump around from one unfinished problems to other problems. they should finish the first problems first.

[roryb18]

lets face it we'll all die in time it dosnt matter how it all ends. you wont find out but you'll never see it...

[humanist7117]

How can dark matter both pull galaxies together into superclusters and yet make the universe expand forever?

[Muxxyy]

it doesn't make universe expand. it's the force of explosion that drives expansion. dark matter will make sure that universe collides upon itself (contracts) once expansion slows down.

[infinitenight2093]

@Muxxyy the big bang shouldn't be thought of as a "normal" explosion. This is because it is not an explosion of matter IN space, it is an explosion OF space(its not really an explosion at all, just a fast expansion). As well Dark Matter would not make the universe collapse in on itself because it is repulsive of gravity. It is the total amount of regular matter in the universe (gravity) that would cause the "big crunch", while it is dark matter that pulls everything apart.

[Muxxyy]

@infinitenight2093 yes, i am aware of that (now) :) kinda made a previous comment a year ago! ^_^ what fascinates me is the fact that expansion of the universe is the driving force for our understanding of "flow of time". since it's the moving away from initial point that creates an illusion of time having passed. once it stops expanding or starts shrinking..how will we perceive reality?

[marespand]

@Muxxyy so the big bang is not the creation of the universe but rather the expansion of the universe.... but if the universe would eventually contract, would it cause another big bang expanding a secondary universe? an on going cycle that has forever been an forever will be??

[sbergman27]

@Muxxyy : Except that we now know that the rate of expansion of space itself is actually increasing. Dark Energy clearly dominates over matter (both normal and dark).

[SmokeWeedEveryHour]

@Muxxyy That actually isn't certain. We're not exactly sure how much mass is in our universe. It could go either way, it could expand and cool down forever, or if there's enough mass, it'll contract into a big crunch.

[youloob2]

oops i hope the owner of this thread can edit that last message for me lol... doesn't even need my name on it, thnx.

[youloob2]

much like einstein's idea... juz that the gravitational should be a pimple not a dimple :P

[youloob2]

wait... wouldn't it make more sense if gravity is a push... then we don't really need the dark matter 2 explain everything... in fact why doesn't the sun juz pull us off the earth, plz some sum smart tell me y. i'm smart but not energetic enough 2 do the math sorry world.

[NukesnIvies]

"why doesn't the sun juz pull us off the earth"

The amount of gravity pulling you is effect by how close or far away you are. Since your ON earth its gravitational feild keeps you on this planet than rather having u fly into the sun... If gravity were to push us away rather than to pull us closer then we wouldnt have any galaxies or solar systems at all, we'd be flying apart from each other

[518schenectady]

so basically the universe could have one of 2 outcomes. 1 we expand forever everything cools down stars burn out and there is nothingness. 2- the universe stops expanding and starts contracting until we have the opposite of the big bang theory

[doomkun]

so what you R saying is we are doomed either way? The End of Time

[WOWFPS]

Lets hope for the big cruch, that way maybe everything in the universe will get pulled together into a point os singularite and then explode under the pressure of all that matter being so compact... (thats another bing bang) and maybe we will all live again? xD

[NukesnIvies]

and if we drift apart far enough then we have nothing in the middle again just like before the big bang and whatever start the big bang (perhaps vacuum energy) it will recreate another big bang.

[DappleLeef]

I completely agree its kinda like recycling everything starts over again (lets hope)

[fusionfreq]

if the universe expanded forever and cooled?

What will all the energy turn into? I thought you can't destroy energy, only convert or store it :?

[tHoM0r]

it cools because as the universe expands, the density of the universe decreases. Its like spreading out a constant amount of energy over bigger space.. so the energy density is less overall.

[midnight9wanderer]

it may actually never reach the final zero but it will, or the distant particles of it will, get colder and colder at increasingly long intervals. maybe it will turn into a universe of neutrinos, lol? 'mass' is really not understood thus the speculation about a Higgs mechanism.

[fusionfreq]

interesting thanks.:)

[walmansa]

thank you Gravitationist

[srarmageddon]

the great attractor... sounds like chuck norris

[ferkinskin]

groovy!!thanks!

[rmrsgirl]

thank you