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What light can teach us about the universe – Pete Edwards


How and when did our universe begin? How did it get to look like this? How will it end? Humans have been discussing these questions for as long as they’ve been around
without ever reaching much agreement. Today, cosmologists are working hard
to find the answers. But how can anyone hope to find
concrete answers to such profound questions? And how is it possible to explore and study
something as huge as the universe, most of which we’ll never be able to reach? The answer is light. And although light from
distant parts of the universe can take billions of years to reach us, it carries six unique messages
that, when put together, can disclose an amazing amount
of information to astronomers who know how to look for it. Just as sunlight can be split up
into the familiar rainbow, splitting the light from distant objects
exposes different patterns of colors depending on its source. This distinctive light barcode
can reveal not only an object’s composition, but also the temperature and pressure
of its constituent parts. There’s even more we can
discover from light. If you’ve ever stood on a train platform,
you might have noticed that the train sounds different
depending on its direction with the pitch ascending
when it approaches you and descending when it speeds away. But this isn’t because the train conductor
is practicing for a second career. Rather, it’s because of something
called the Doppler effect where sound waves generated by
an approaching object are compressed, while those from a receding
object are stretched. But what has this to do with astronomy? Sound does not travel through a vacuum.
In space, no one can you hear you scream! But the same Doppler effect applies to light
whose source is moving at exceptional speed. If it’s moving towards us,
the shorter wavelength will make the light appear to be bluer. While light from a source
that’s moving away will have a longer wavelength,
shifting towards red. So by analyzing the color pattern
in the Doppler shift of the light from any object observed with a telescope,
we can learn what it’s made of, how hot it is and
how much pressure it’s under, as well as whether it’s moving,
in what direction and how fast. And these six measurements,
like six points of light, reveal the history of the universe. The first person to study the light
from distant galaxies was Edwin Hubble, and the light he observed was redshifted. The distant galaxies were
all moving away from us, and the further away the were,
the faster they were receding. Hubble had discovered
our universe is expanding, providing the first evidence
for the Big Bang theory. Along with the idea that the visible universe
has been constantly expanding from a densely packed single point, one of this theory’s
most important predictions is that the early universe consisted
of just two gases: hydrogen and helium, in a ratio of three to one. And this prediction can
also be tested with light. If we observe the light from a remote,
quiet region of the universe and split it, we do indeed find the signatures
of the two gases in just those proportions. Another triumph for the Big Bang. However, many puzzles remain. Although we know the
visible universe is expanding, gravity should be applying the brakes. But recent measurements of light
from distant dying stars show us that they’re farther away
than predicted. So the expansion of the universe
is actually accelerating. Something appears to be pushing it, and many scientists believe
that something is dark energy, making up over 2/3 of the universe
and slowly tearing it apart. Our knowledge of the behavior of matter
and the precision of our instruments means that simply observing distant stars
can tell us more about the universe than we ever thought possible. But there are other mysteries,
like the nature of dark energy upon which we have yet to shed light.

Reynold King

89 Replies to “What light can teach us about the universe – Pete Edwards”

  1. So humans were made by the universe, which in turn made things from the universe, to explore the universe? Wow, that's kind of trippy.

  2. This video is only for those who believe in the big bang. Gravity is too weak. Electro-Magnetic Universe rules.
     Of course here will come the people out of woodwork who will say people just do not grasp something because they disagree with the big bang, gravitational model.

  3. where do we live in, in a part of what? and this part is part of what? is this the ''everything''? what is the everything, when created, what was there before this created??  I ask those questions to my self since I was 9-10 years old… yet I have only answered one, we live on earth, the safest planet, why? because we live.

  4. The sound effects in this video gave me headache :s. Fun video nonetheless (even though i already knew most of it) 

  5. I like how people always know about such things and yet they claim that there is no god, this it self proves that there is someone who created this.

    Anyways idiots will always say "Nothing created nothingness which created the nothingness that created an explosion thus the universe was born from our lovley nothing"

  6. It's obvious God created the universe. People will believe that the big bang happened by itself from absolutely nothing, but won't believe that an Almighty God spoke it into existence. It's in the first chapter of Genesis. Trust in God and put your faith in him.

  7. I always hear the term 'Doppler Effect' being thrown around but now I finally fully understand what it is!

  8. Still unsure why people think is crazy to think we were created by God, but its not crazy to think random events created everything from nothing. If I make a car house (like small scale obviously) out of Legos and said "I made this!". People would believe me. If I said "His house was made by nothing, it randomly came together!". People would think I was crazy. 

    But somehow that logic doesn't apply to the universe. Sounds to me like people don't believe God created the universe because its scares them theres more to life then it being pointless. It scares them that even though they have free will, their afterlife could be them in hell. Which also scares them because it means they would have to change their worldly life. 

    If I am wrong then explain how my lego house versus the universe examples are different from each other? Truth is people know God created everything, but its to hard for people to accept.

  9. I love it. So big and scary and yet so fascinating.
    Now imagine how much we could achieve,if we stopped bombing each other for like one week.

  10. I think we'll only understand the universe for just a glimpse at the moment of death/birth. It's just a bit of a can of worms downloading that into language.

  11. Many people are unsure and that is fine. But those who are certain in their belief that God does not exist, know that the matter would have been settled had it not been for God's promise 'that i will surely fill hell with men and jinns.'

  12. I dont subscribe to the ideas of big bang or dark energy. Yea it is expanding, but i think there are much better explainations

  13. Stop talking about god, you idiots! This video is about light and how it reveals properties of our universe. Talk about that!

  14. Says sound cannot travel in space. Sound effect of an explosion happens at 2:13. Good video nonetheless, but I had to point that out 😛

    Unless the universe was dense enough for sound to travel after the Big Bang.

  15. UNIVERSE. Such an amazing word. It's such a bummer that the universe is inevitably going to end but maybe humanity's going to find another universe if the MULTIVERSE Theory is true and if our technology allows it by that time.

  16. I'm a non-English speaker so it's difficult to fully understand when the video clip says scientific,medical things and it makes me study more. I hope I can understand every TED video someday:)

  17. Comparing to other vids here, this one would be too hunting for me to watch as a child due to frightening sound design. Heck it sounds pretty disturbing for me even now. Just saying. This and the quality of voice recording. Other than that, nice piece of iformation 🙂

  18. "In space, no one can hear you scream" is the tagline for the (Ridley Scott) film Alien —and is one of the most quoted / parodied in film history.
    This quote is an oversimplification of fact. Yes, the vacuum of space transmits sound poorly—so you would not be able to hear anything.  Yet, to scream, you need air, so no one would hear you scream because you could not scream.  That is, unless you were in a spaceship or space-station—and then, others there could easily hear you scream —or sing Space Oddity —or whatever.

  19. there is no such thing as dark energy. its crap, big bang and red shift as being the proof of expansion is also false, there is alot of evidence and work being done by scientists that show the falsehood of mainstream understanding of the cosmos, while mainstream science literally fits the evidence to their theories if that evidence goes to the contrary of what that theory predicts. 

  20. Can a star redshift or blueshift to the point of being invisible? If so are there still ways for us to detect them?

  21. I believe that dark energy affects everyone and you can controll that energy if you are already awakening. That's why some people i know are lucky because they know how control it. They manage to control which energy will enter to them

  22. I'm not an expert, but I don't believe that red shift makes things appear redder. It is impossible to know what the original colour of an unknown source was. Red shift means – as far as I am aware – that any interference lines are shifted towards the red end of the spectrum, not that the light itself is redder. I am open to contradiction.

  23. I was wondering how far I would have to scroll down the comments before I saw some knucklehead prattling on about 'God'.  Second post. 

  24. Q:
    There are colliding galaxies,
    galaxies that move away from each other,
    and galaxies that are in a standstill
    to each other?

    There is a redshift in the light of faraway galaxies
    also when the galaxies are in standstill
    to each other?
    Or not?

  25. god is life. god is love. god is the collective consiousness of our positivity. he is everywhere. he is in everything. we evolve through love and living. loving creation. god is a lovely artist. god is purposeful. god is not hate. god is not discriminatory. god is not destructive. free will is a gift of god without it love is not true.

  26. How can we say something is 1000 or more light years away when we have been recording these things for maybe 100 years?

  27. and its very sad for me if others does not believe to god if they were judge may be they will be punished entirenaly in hell

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