First light: Revealing the Early Universe - Chris Lintott
Vložit
- čas přidán 9. 07. 2024
- The final lecture in the series returns to the theme of how insight is derived from observations, considering the cosmic microwave background.
This oldest light in the Universe, emitted just 400,000 years after the Big Bang, contains the seeds of the structures we see around us, and tells us about conditions at the Universe's beginning.
It will also consider how measurements of the Universe's expansion, made using the CMB, are leading to unexpected results, creating tension in modern cosmology.
Chapters
00:00 Introduction
02:48 Why we only see the cosmos in the past
06:58 Why JWST is an infrared telescope
10:16 Vesto Slipher's discovery that distant galaxies are redshifted
13:39 How Hubble's redshift work led to him discovering Hubble's law
18:21 How the Big Bang Theory developed
24:47 Project Echo
26:04 Telstar
26:44 Penzias and Wilson's discovery of cosmic microwave background radiation (CMBR)
32:45 Why does the universe have CMBR?
35:56 How the discovery of CMBR proved the Big Bang Theory
41:00 Why we can't explain the current expansion rate of the universe (the Hubble tension)
44:05 How new observations in Chile may solve this problem
46:25 Conclusion
48:03 Q&A Session
This lecture was recorded by Chris Lintott on 29th May 2024 at Conway Hall, London
Chris is Gresham Professor of Astronomy.
He is also a Professor of Astrophysics at the University of Oxford, and a Research Fellow at New College.
The transcript of the lecture is available from the Gresham College website:
www.gresham.ac.uk/watch-now/f...
Gresham College has offered free public lectures for over 400 years, thanks to the generosity of our supporters. There are currently over 2,500 lectures free to access. We believe that everyone should have the opportunity to learn from some of the greatest minds. To support Gresham's mission, please consider making a donation: gresham.ac.uk/support/
Website: gresham.ac.uk
Twitter: / greshamcollege
Facebook: / greshamcollege
Instagram: / greshamcollege
Always enjoy Chris' talks. Thanks to all the team involved for making this happen!
I love this guy. ❤ & all your physics lectures.
just a marvelous presentation and presenter. Thank you
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!
Unfortunate choice of verb….
Outstanding lecture.
Thank you for an enjoyable and informative series of lectures on a fascinating subject.
My pleasure! Back next year
I'm beginning to get hooked on Astronomy again, after watching a few of Chris' talks. Thanks Gresham , nice work.
Excellent. Keep up the great work. More please.
11:15 Our favourite ex-planet always finds a way to come up in these talks.
Was very pleased to get it into a lecture on the CMB!
Keep watching the Sky at Night, the world's longest running tv science programme. Thanks, BBC.
This was a fantastic talk, thank you.
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.
Thank you Chris
Don't ever stop Chris 👍🤗
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?"
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.
Nice tv
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
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.
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
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.
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
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!
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
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?
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.
@@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.
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”
Use Metric, its science! Now your using Miles, feet and the Metric system in this video...its a chaos..
Can somebody please elucidate on the idea that gravity travels at the same speed as light. Gravity travels??
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.
Yes. In relativity, there’s a speed of gravity! If the Sun disappeared, it would take eight minutes for the Earth to ‘notice’.
@@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?
@@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.)
@@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.
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
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)
@@jonathonjubb6626MOND does have some interesting aspects. Still not been completely ruled out...
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...
@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.
Здравия всем. Испытаем ❤фонарь для гравитационных квантов❤ посмотрим на Вселенную? И возможно квантами гравитации (цифровым способом) измерим Вселенную? Соберём учебное пособие для школ и ВУЗ, с помощью «ГИБРИДНОГО гироскопа». Вы сможете совершать научные открытия; по астрономии, астрофизике, космологии, высшей теоретической физике,...
Обращаюсь к Вам с предложением на совместное изобретения ГИБРИД гироскопа из некруглых, ДВУХ катушек с новым типом оптического волокна с «полой сердцевиной из фотоно-замещенной вакуумной зоной или (NANF)», где - свет в каждом плече проходит по 250000 метров при этом, не превышает параметры 84/84/84 см., и вес - 24кг. Предприятия по выпуску "Волоконно-оптических гироскопов" может выпускать ГИБРИД гироскопы, для учебно практического применения в школах и высших учебных заведений.
Эйнштейна мечтал измерить скорость поезда, самолёта - через опыт Майкельсона Морли 1881/2024 г., и только тогда, опыт будет выполнен больше чем 70%. Это возможно выполнить с помощью оптоволоконного ГИБРИД гироскопа. Вот исходя из выполненного более 70% опыта Майкельсона, возможно доказать постулаты: Свет - это упорядоченная вибрация гравитационных квантов и доминантные гравитационные поля корректируют скорость света в вакууме. (Мы, не ищем эфир, мы увидим работу квантов гравитации)
В итоге увидите *теорию всего* в простом учебном устройстве.
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.
So that people can say things like "earth" and know what they're talking about.
"It works. It’s amazing" - when will it stop working and why?
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!
I cannot think of a more rewarding life than advancing knowledge. What is it you do?
@@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.