Carolin Crawford is one of my favorite professors (for her lectures and the topics).

wow. wow. I have watched so many youtube videos on cosmology and this is the clearest, the best, the most easy to understand. I am a lay person but to me this just made sense. So impressed by this content. 60 symbols should create a special program just to comment on this video.

Professor Crawford is a great speaker and I love listening to her amazingly interesting talks.

Would like to say to you Carolin Crawford that I think I have now seen all your youtube talks and for both clarity and delivery they surpass anything I have watched. You really are a credit to your profession and to the dissemination of knowledge to ordinary non-academics like myself. I thank you profoundly.

I've watched a number of your presentations and find your style very easy yet informative for an armchair enthusiast such as myself. I have to say that "magic pushy stuff" had me chuckling for quite a while :)

Makes one want to applaud even here on KZfaq. Oh wait, I can! 👏👏👏👏👏👏👏👏👏👏👏👏👏

Thank You Professor Crawford.. Your presentation is a credit to you and your college. It was one of the best I could find that made sense and clearly delinated what we do not know about our Universe. Universe is a system in the process of changing. Understanding this process is coming along slowly. New Theories need to be formulated and verified regarding what you presented. The Theory of what existed at the time this universe was a "singularity" is soely needed. I hope to find some in and out of the normal channels. Maybe you mibht have one.

Enjoyed that.. covered a bit of ground there quite succinctly

She did not mention CELIA PAYNE, the first person to realise the sun was made of Hydrogen & Helium using spectrography) Everyone before thought it was primarily IRON. She almost lost her job for the discovery / realisation. COME ON. WOMEN SHOULD ATLEAST support their predecessors.

I like this video of how to measure large distances in the universe. It also shows how distant galaxies are moving (fast or slow; away from us or not seeming to move at all). The further away galaxies are the faster & the more they seem to move away and the closer they are the more static or non moving they seem to be. 'FOOD FOR THOUGHT": I think that space and matter are locked in a dynamic "of opposition" with each other (like positive & negative electricity). Matter displaces space.

After watching this great lecture, these two wild presumptions have reached my imagination: 1 that the acceleration of the expansion of the Universe did not start 6B years ago, but ( just like the expansion of the universe isn't apparent in closer galaxies and stars) this characteristic begins to being measurable at those distances. 2 That since supernova works through gravity as inward push but not fuelled with nuclear fusion as the outward push, (professor Crawford at the begin of the lecture tells that in the past they didn't know what fuels the sun, because they didn't know about fusion), the maths of those might give the next level of complexity in transformation of matter to energy.

of course we are using the amount of time for earths days/nights and years. but we have to have it under other planets and see if the amount is the same depending on a different planets gravitational pull and speeds effect on time.

i really enjoy her talks

I'd love to see the primordial nuclear synthesis lecture.

you should watch the talks by Professor Ian Morrison (also provided by Gresham College). Very informative.

I wonder if you are aware that Andromeda (Messier 31 In our local group) is actually coming our way. In around 4.5 - 5 billion years it may actually collide with our own. Luckily, that's a very long time!

That was great! As usual. Thanks for upload.

u have to remember and what many ppl don't realize is a lot of these objects we see in space, from their perspective we don't even exist yet

Yes. The latest we have on this estimate is 13.82 billion years ago from data from the Planck satellite. Worth looking up! Cheers.

So, the Hubble constant is not a constant anymore. How is it called now. The Hubble "thing"?

very very good lecture.

So what is the reasoning to say hydrogen and helium can form but heavier elements would not form in the big bang?

"magic pushy stuff" lol , I like that name ;)

So for the most basic super nova, what is the nuclear reaction that creates the power of the explosion?

I have a question. Since the BB the universe is expanding. And the universe is the totality, then surely any set distance will change as expansion occurs. ie. kilometre today is longer than a kilometre at the beginning of time as it is the same distance from a to b, but now a and b are much further apart purely because the dimensions they live in have expanded. Does that make sense? If so, time is a dimension, so surely that will have expanded too... 1 of 2

at the end, she says 13.772 +/- 0.059 billion years.

Foolish clouds without water, ever learning & never able to come to the fullness of knowledge of truth.

Odd that you look in any 3-D direction and you find a 13B year red shift early galaxy and the visible edge of our spacetime. And the initial flash/background which started at some visible frequency has been stretched by spacetime to the current level of 13B years in our local time. That's nice but why are we in the center of this visible expanding space, probability should say you should be a lot closer to some edge. We should run out of galaxies in some direction before 13B years, having us at the center means something is wrong. They don't know what is outside our 13B year visible event horizon, they can't even say it's not 20B light years or 100B light years. I took a cut rubber band, made a 1cm mark at one end of slack rubber band called it our 13B universe at 6.5B years, made another set of marks at the other end and called the same thing as us beyond the event horizon. Then I stretched the rubber band till the our visible was current (13B light years). Our edge moved 6.5B light years in 6.5B years or near speed of light (highly red shifted). The other space's edge (marks on other end of rubber band) moved 60B light years (with respect to our reference) in the same time because of the middle additive effect, the light/gravity/etc of that space never has a chance of reaching us. Tough within the other's frame of reference we are the one moving fast and the edge of their visible universe is as large and moving the same as ours.

It still feels like there are a lot of assumptions in this theory. Like, knowing the oldest light, knowing the oldest stars, knowing there was a big bang. How do you know which direction the universe is headed if you don't even know where your position is relative to the rest of it? And isn't possible that there is older light in the universe that has not reached us yet? I'll keep reading.

Then surely we have no meaningful means of gauging the age of the universe as time is expanding like the other dimensions. Or am I talking bollocks? this has been bothering me for a while. Anyone able to explain it to me?

Smart people always find a way out

So, you measured the age of the universe by observing (at light speed (C) all the galaxies....and it is 13.75 billion years old? Are you sure that your eyes flush at light speed? or just you want to put your faith on 'photons'? thanks.

So i got one question... if the visible universe is 93 000 000 000 light years ... the light from the most distant point travels to reach us right?... it takes 93 000 000 000 years to cross from one point to the end ... so if the age of the universe is 14.5 billion years and the light has to travel 93 billion years away to reach us ...how is this possible if the age of our universe is only 14.5 billion years ?!?!?!?!? you feel me what im tryin to say?!?!

four and a half magical missing atoms not three - I can't count.

I'm not totally convinced regarding the presence of dark matter/energy. I think that there's a much simpler explanation, and that is that the universe is still very young, still in the initial stage of its explosive expansion. Like the explosion of a sphere of Semtex, as soon as the detonator has activated, in those first few nano-seconds, the distribution of the material that comprises the plastic will be somewhat "clumpy," or non-uniform. The initial expansion stages of the explosion will be very rapid, as compared to the later stages. There may be secondary, tertiary or even further, blast waves that interfere, or reinforce or even harmonise with the initial blast wave - or not! This could produce differing rates of expansion, maybe even pulses of expansion. This is all pure conjecture, of course, but it might be interesting to rig up some very high-speed cameras to examine such an explosion. It would be an extremely cheap experiment, as far as these things go, and it may or may not shed some light on the current problems regarding our knowledge of the age and consistency of our universe. Even if it provides no further useful information, it would be a fun day out for cosmologists! It's my belief that the universe is, in fact, very young indeed. But as I'm not a scientist of any kind, no-one is going to take me seriously. Or am I just being stupid? Anyone?

Carolin, i am sure we are some years away from the big rip. Do you believe that in the time prior that GOD may intervene?

I don’t understand the logic in the the conclusion that the expansion of the universe is speeding up. If we see a supernova at great distance and the event is further away than we would expect why does that mean the expansion is speeding up? If an object with the same redshift is further away than expected, that would mean it is receding from us at a speed that is slower than would be required to be at that place, and I would expect that is therefore must have been receding more fast in the past ,and thus the expansion would be slowing down. However the opposite is claimed. If a supernova was further away than it’s redshift would indicate , it is supposed that the expansion has been speeding up. Can anyone explain why a smaller hubble- factor would indicate a faster expansion?!?! I am baffled! It really doesn’t ,make any sense! Yet I hear this time and again and nobody even thinks it is worth explaining. Am I that stupid?

FFS! The creatards turn up everywhere!

Look at the BBC article this week from the Planck satellite: .bbc.co.uk/news/science-environment-21866464 It kind of brings this lecture a little more up-to-date. Cheers.

Olinto de Pretto formulated and published the E=MC2 in 1903. Albert Einstein as usual "borrowed" it .

the universe (as vast as it is) is only 3 times as old as earth? umm...that's hard to believe, and kind of disappointing. I mean, how much of the universe is unobservable to us?.........my point exactly!

So the theory explains 5% of the universe, and they have no idea about the other 95% sure sounds good to me. They invoke the tooth fairy to eplain that nothing created everything, then two more times for dark matter and dark energy. How about maybe the theory is wrong?

all seems very woolly that last bit. far too much to cover in an hour if you need to explain every concept in the process of finding an age for the universe. personally I get using supernova as standard candles and would rather hear more about the cmb blotches and how they are sure of the size. Thus the flat geometry/critical density of which they seem so certain despite only being able to account for one and one half of the hydrogen atoms per m (cm?) cubed they need for it. Carolyn was perhaps more upfront than most in calling the theory of the other 'missing' three and a half atom's-worth "magic" but where physicists use words like "dark" and "virtual" I can't help wonder if "wrong" might be closer to the truth.....

I want to know more about "Dark Pushy Stuff". You have just started a whole new conspiracy, lol.

Ok at kzfaq.info/get/bejne/r9WTdb2hza3Sdps.html#t=2114 she says the slide are wrong and she is embarrassed, but they are actually right I think. Not sure what is wrong?

I hate this comment rule, now I have to check my comments on google + !!!!!!

can scientists be honest and say we dont know rather than throwing bullshit arguments the age of the universe cannot be determined period

Magic Pushy Stuff MPS

the solar system doesn't even exist

I get this video when I click on something else....what?

if evolution has taught scientist anything,it should be not to build their houses of cards all too high since the first card is laid on an assumption.when you find out later that assumption was incorrect you don't want to have to dismantle a skyscraper due to foundation stone being a marshmallow. i loved science in school,still do love 'real' science,but i understand,colleges keep spewing forth phd's,and they want to study 'something' and they want grants and funding,so now comes all the sno jobs,shovel loads of crap etc.gotta come up with some kinda song and dance to keep their funding.best part is you no longer have to prove anything,and the more obscure and unprovable it is the better,can't prove it ,can't disprove it ,yay,they can go on not only for their lifetime but generations to come,yay,learned anything? no ,what, was that the point? doh!