Alexander Vilenkin - Why is the Universe Expanding?

We know our universe is expanding—this is one of humankind's seminal discoveries. What caused such colossal expansion? We call it the Big Bang, but what were the forces involved? How do they work? What are the implications for understanding the cosmos? And why is the expansion of the universe accelerating? What does this hold for the future?



Alexander Vilenkin is a Professor of Physics and Director of the Institute of Cosmology at Tufts University.


Closer to Truth presents the world’s greatest thinkers exploring humanity’s deepest questions. Discover fundamental issues of existence. Engage new and diverse ways of thinking. Appreciate intense debates. Share your own opinions. Seek your own answers.

[TheGidmid]

4:35 "we have no fukin idea"

[mathbrainius]

This is a really interesting explanation. Thanks!

[patrickboudreau]

Its amazing trying to imagine what it is expanding into. Absolutely nothing comes to mind, a total blank.
The feeling you get when you realise you can’t imagine a place without space is mind bogling.

[СумеречныйхранительНавсегда]

Dr. Alexander Vilenkin Is Super Cool ( Awesome Video )

[robotaholic]

This was a reverse interview. Robert explained the expansion, and Vilenkin confirmed and clarified. It worked, though. I have watched these videos for so long that it feels like I know these people. I am so appreciative. To have this kind of access at a whim is spoiling me. Thank you

[alien]

The big bang was named that way on purpose because it was obserd, this is fact. The big bang merely points to the reference " expansion from a singularity"

[matthewsands]

Perhaps the edge of our universe has a gravitational pull due to a greater pressure/energy existing on the other side (outside of it).
Like how the expanding space inside an expanding suction cup would create a similar phenomena with any matter inside the vacuum.

[MrKydaman]

Alexander Vilenkin is brilliant and I would love to see a more from him.

[lassydogpie]

I want to know how everything in the universe came from nothing.. it’s impossible that we’re here

[caveyful]

The reduction in gravitational field strength will result in a slower rate of time due to time dilation making it appear to an outside observer (us) that universe is acceleratively expanding

[leeberry]

So the farthest galaxie are moving pritty much the same rate of speed as we are. Every galaxie is the center of it's universe doesn't matter which. And when experiments are done and done correctly that's where they should start from the center of your universe. So if someone says those galaxie are moving at the speed of light say to them from where your standing.

[aadxb]

Robert was trying to get him by balls but the scientist became more humble, he even agreed to almost everything.

[Slarti]

What if we are just existing on the outside of a bubble which is expanding?

[shivavrd]

When he says.. "The recent cosmological epoch, like last billion years.." You can understand what's the order of cosmological magnitudes!!

[stoneagedjp]

In the far future when only a few galaxies are visible, what kind of theory about the creation of the universe will intelligent life come up with? And whose to say that we are not similarly denied information crucial to understanding the universe?

[apparaodasari]

The World must know about formation of the Universe, as quickly as possible . This type of videos are spooling the youth . Without knowing about formation of the Universe, how can anyone discuss about the facts of the Universe ? Why the Universe is expanding ? Is it a question ? First the World must know about formation of the Universe .

[redmed]

What about the fact that galaxies are moving away faster the further away they are? Are they going downhill or is it like looking through a weird magnifying glass. Weird does not describe it.
How strange is it to be anything at all.

[transamericanlife]

Even to great physicists do not truly have a way to understand the underlying mechanics of spacetime.

[stewartbrands]

If a line is drawn in any direction to infinity does that not imply there would be "infinite" more masses associated with that line the longer the line is? For instance at 1billion miles there would be more mas relative to local mass, and at 2billion miles there would be even more mass relative to the local mass.
Therefore in all possible directions there would be a pull of gravity associated with any direction(since any direction would proceed to infinity thereby representing increased mass in space the further along relative to the local starting reference you go) .
So there would be expansion toward that infinite mass out from any local region you chose in any direction due to gravitational expansion.
This would mean so called dark matter is an unnecessary concept to explain expansion, since gravitational forces would be sufficient.

Given that the further out from any local space there would be ever increasing amounts of mass between say you(local space) and infinity.
Has this sum of collective mass to infinity been considered as a function of expansion?
If not why has this gravitational summation not been considered?
If M increases, then F increases and if there is more and more mass accrues the further toward infinity from a local space one bobserves would that not mean there is a gravitational force of ever increasing value in every direction from every local space with the consequence being exponential expansion?

[desmonddwyer]

Surely the reason is lack of gravity, the further galaxy's are from each other the less pull they have on eachother.