First light: Revealing the Early Universe - Chris Lintott

[@user-wr4uz8pg7m]

Thanks so much for these excellent lectures Dr Linott and Gresham College. What a wonderful time to be alive when this knowledge exists, and when it can be presented to a general audience both in person and electronically throughout the world (and beyond?). Looking forward to future talks.

[@stevehurford3531]

I'm beginning to get hooked on Astronomy again, after watching a few of Chris' talks. Thanks Gresham , nice work.

[@natures_child]

Thank you for an enjoyable and informative series of lectures on a fascinating subject.

[@chrislintott1]

My pleasure! Back next year

[@spaceinyourface]

I love this guy. ❤ & all your physics lectures.

[@inamortz2372]

Always enjoy Chris' talks. Thanks to all the team involved for making this happen!

[@2nostromo]

just a marvelous presentation and presenter. Thank you

[@bazsnell3178]

Before the famous ''Sky At Night'' presenter Patrick Moore died, he groomed and introduced his successor Chris Lintott into his old role. A very worthy successor indeed!

[@K1lostream]

Unfortunate choice of verb….

[@agxryt]

Groomed might be the worst word to pick here lol

[@margaretbloomer9001]

Keep watching the Sky at Night, the world's longest running tv science programme. Thanks, BBC.

[@Jobby1975]

Excellent. Keep up the great work. More please.

[@garydecad6233]

Outstanding lecture.

[@numbersix8919]

This talk isn't about the first stars, or the early universe, it's an introductory overview of modern astronomy.

[@GlassEyedDetectives]

This was a fantastic talk, thank you.

[@PetroicaRodinogaster264]

my brain hurts though when they talk billions of light years. But it makes anything that happened in the last million yrs on this planet seem like yesterday to me.

[@GlassEyedDetectives]

@@PetroicaRodinogaster264 The fact that we can imagine it and wonder is enough for me, let alone try to explain it! 😁

[@LeighOlive]

Thank you Chris

[@adrianaspalinky1986]

Don't ever stop Chris 👍🤗

[@mawkernewek]

11:15 Our favourite ex-planet always finds a way to come up in these talks.

[@chrislintott1]

Was very pleased to get it into a lecture on the CMB!

[@tombruner9634]

At the risk of sounding simplistic, I would suggest that the question "what is the universe expanding into" is difficult to answer is because it is based on a false premise. A better question may be "what is there when the universe isn't?"

[@chaosking911]

I love when a suggestion is a thought experiment in irrelevant nitpicking.
10/10.

[@atticuswalker]

since the refraction index of all transparent material is the difference in density between mediums. and the mass in the universe was less densly packed together at the start. then wouldn't the difference in density over time be reflected in the light from the early universe. if the speed of light is constant.

[@petersq5532]

if the space itself expanding it remains the question, what is space? what does it expanding to? where the extra space coming from?
it appears that another layer of existance could be wrapped around our 3D world. or magic

[@accessdenied3379]

What a magnificent way of explanation! I loved it. Thanks. One thing that came into my mind is that, if the expansion rate of the universe as explained, then, will there be a time when the maximum distance of our observable universe is going to come to an end? I guess you got my point!

[@chrislintott1]

Because the expansion is accelerating, the fraction of the universe we can see is actually dropping. Which is slightly mind boggling. If nothing changes in the far future we will only be able to see our own galaxy

[@jacktapping1898]

Nice tv

[@carlbell2226]

Nothing is never early everything and everyone is going to be late

[@diogenes9524]

1. Any 'objective' observation places the observer outside the subject system, so your reply to the question 'what is the cosmos expanding into' must surely apply to any observation. 2. Quantum theory shows that particles and waves behave differently when observed. Could this phenomenon account for the Hubble tension? Thanks for clear explanation and presentation.

[@GordonShuffell]

I like the theory that the universe is contained within a black hole we could never escape it but stuff might be able to fall in from out side

[@petersq5532]

we experience a faster expanding universe. but as this lecture pointed it is an illusion. the speed of the expansion is the same but more bits are expanding at the same time. so the later contraction does not go against the observation. it is not fundamentally contradictive.

[@JoeBlowUK]

Trying to work out how the Great Magician pulled off the greatest trick of all.

[@petersq5532]

if we see the past farther and further with distance, how can we draw the lovely looking map of supergalaxies and all the network of clusters? it is like a google map compiled from historical photos , older and older as we go away from the centre. how reliable any conclusion from it?

[@chrislintott1]

Yes, if you go far enough then you are indeed comparing the past to the present. The map I showed is about a billion years across in travel time, which is small enough that we tend to consider that all the present day.

[@petersq5532]

@@chrislintott1 thank you for your answer. in that range it appears uniform. so the question remains that for how long you can extrapolate this result.

[@fractalnomics]

Great lecture, respect. I had this thought the other day: is the observable edge of the universe, the age of the universe, really a time dilation barrier; where time stops to the observer, us, in this case. I wrote my idea in a paper (original thought and no AI added); I think it solves the problems JWST is presenting us. Comments

[@timhannah4]

If the Universe is expanding, how come Andromeda will collide with the Milky Way?

[@executivesteps]

The mutual gravitation of the galaxies in our local group of galaxies overcomes the expansion rate of the Universe.

[@georgenorris2657]

Can somebody please elucidate on the idea that gravity travels at the same speed as light. Gravity travels??

[@bipolarminddroppings]

It's not an idea, it's an established fact.
The speed of light is a misnomer, it should properly be called the speed of causality. It falls out of maxwells equations and also out of special and General relativity.
We know it's true because we have measured gravitational waves. We have 2 observatories on opposite sides of the earth, they detect the waves at slightly different times, we calculate the difference and get the speed of light.
If you want to know more you really need to go Google it.

[@chrislintott1]

Yes. In relativity, there’s a speed of gravity! If the Sun disappeared, it would take eight minutes for the Earth to ‘notice’.

[@georgenorris2657]

@@chrislintott1 but at the same speed? are light and gravity somehow then connected to one another? at the same speed indicates a complex relationship of some sort doesnt it?

[@cleon_teunissen]

@@georgenorris2657 The connection is not so much with each other, but with the background that allows light and gravity to exist: spacetime. The upper limit to speed is not a specific property of light, nor a specific property of gravity, it's a property of spacetime.
On Aug. 17, 2017, the Laser Interferometer Gravitational-wave Observatory (LIGO) and Virgo detected, for the first time, gravitational waves from the collision of two neutron stars. The event was not only “heard” in gravitational waves but also seen in light by dozens of telescopes on the ground and in space. This event has been given the name 'GW170817', that will allow you to find more information about it. The event occurred 130 million lightyears away. The light produced (in the wake of the gravitational event) started arriving 1.7 seconds after the arrival of the gravitational wave. The 1.7 second difference is attributed to a 1.7 time gap from the event to the start of production of light. (For instance, matter accelerated to high speed colliding with surrounding matter; the resulting heating then gives emission of light.)

[@Michael75579]

@@georgenorris2657 In relativity, c is not just the speed of light but the fastest speed at which any interaction can travel. This means that gravitational waves can travel at a maximum of c, and observations of events which produce both gravitational waves and gamma rays have constrained the difference between the speed of gravitational waves and the speed of light to be extremely small if it's not zero.
Gravitational waves are travelling changes in the shape of space-time. If the Sun somehow instantaneously vanished then space-time where the Sun was would lose the curvature that was caused by the Sun and this flattening would travel outwards. Since it's the curvature of space-time that causes the Earth to orbit the Sun, the Earth's orbit wouldn't change until this flattening reached us 8 minutes later.

[@stoyanfurdzhev]

Still grouping in the dark

[@OpenWorldRichard]

The Hubble tension will be resolved by realising that the Milky Way is around 26 million light years from the centre of a finite universe with a space boundary. This theory matches all observations and explains dark matter and dark energy. Richard

[@jonathonjubb6626]

Nobody likes a smartarse! The HT will be resolved when scientists realise they do not fully understand red shift and probably gravity...
(Halton Arp and also Mond)

[@JohnBeeblebrox]

​@@jonathonjubb6626MOND does have some interesting aspects. Still not been completely ruled out...

[@bipolarminddroppings]

No. It won't be.
Your hypothesis is provably wrong with type 1a supernova.
You don't know enough to know why you're wrong...

[@bipolarminddroppings]

​@jonathonjubb6626 it's actually much more likely that the problem will be solved because lamda isn't a constant.
You don't have the first clue what I mean when I say lamda isn't a constant, and thats why you should be quiet and learn something instead of thinking you know better than actual experts.

[@PetroicaRodinogaster264]

I wonder how he might deal with some boffin at a party who is holding forth that some supreme being said “let there be light”

[@user-wr4uz8pg7m]

How would u handle such a statement if you were well versed in cosmology?

[@gsb5012]

Why on earth are so many wasting their life studying how old the universe is, how it started and how big it is??? It is. It works. It’s amazing. ITS ENOUGH.

[@lafenelson3212]

So that people can say things like "earth" and know what they're talking about.

[@steveclark2996]

"It works. It’s amazing" - when will it stop working and why?

[@margaretbloomer9001]

It's because it's amazing that we want to know more. If we don't look or ask questions, we stagnate. It's because we ask questions (we're human beings, an inquisitive species), we gain knowledge and understanding. We develop technologies. Durrr!

[@Sandbar1914]

I cannot think of a more rewarding life than advancing knowledge. What is it you do?

[@gsb5012]

@@Sandbar1914 advancing knowledge of useful stuff like disease, protecting our own planet and its incredible resources, its wildlife and science, discovering what we still don’t know about it all.

[@zhavlan1258]

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[@marcodekock7875]

Use Metric, its science! Now your using Miles, feet and the Metric system in this video...its a chaos..

[@user-wr4uz8pg7m]

Though your brief statement includes at least four errors, so ... :)