It took centuries, but we now know the size of the Universe

[Judi Lynn]

It took centuries, but we now know the size of the Universe

The sheer scale of the cosmos is hard to imagine, and even harder to put an accurate figure on. But thanks to some ingenious physics we now have a good idea of just how big it is

By Chris Baraniuk

13 June 2016

"Let us go rambling about the Universe." This is the invitation that American astronomer Harlow Shapley gave to an audience in Washington DC in 1920. He was taking part in the so-called Great Debate with fellow scientist Heber Curtis on the scale of the Universe.

Shapley believed that our Milky Way galaxy was 300,000 light years across. That is actually three times too big according to the latest thinking, but his measurements were pretty good for the time. In particular, he calculated broadly correct proportional distances within the Milky Way – the position of our Sun relative to the centre of the galaxy, for instance.

In the early 20th Century, though, 300,000 light years seemed to many of Shapley's contemporaries an almost absurdly large figure. And the idea that other Milky Way-like spiral galaxies – which could be seen with telescopes – were equally large was outlandish.

Indeed, Shapley himself believed the Milky Way must be exceptional. "Even if the spirals are stellar, they are not comparable in size with our stellar system," he told his listeners

More:
http://www.bbc.com/earth/story/20160610-it-took-centuries-but-we-now-know-the-size-of-the-universe

[Android3.14]

1. How annoying. The headline makes a promise the article fails to keep.

Observable universe is possibly infinitely small compared to the universe.

[Orrex]

2. My observable universe is a gray-beige cube five feet on a side.

[Jerry442]

6. Yes, but outside there may be a Dark Wally...

...with no observable output.

[Thor_MN]

8. You have cube walls? You lucky bastidge...

We are about to go from 6 foot open desks to less than 5 foot mobile desk in an effort to "densify". Our building is out of space, so the obvious solution is to just pack more people in nilly willy. Since the desk are "mobile", we can arrange them however we want - i.e. a disorganized mess. One area of the building has already switched and it looks like a office supply store puked in there. Our turn is in the coming month and we go from a minimal divider on the back of our desk to only having our monitors to block you from staring at the person across from you...

[Javaman]

13. you want to talk density? Here' my office...;)

[hunter]

18. I like how the started filling the pool neatly...

... and about halfway through the job they gave up and just threw stuff in.

[Javaman]

21. someone said, "don't worry we have plenty of time!"

then time ran out and someone said, "don't worry about neatness, no one cares! just throw it in!!!"

of course, along the way, someone asked "why the pool?" and got the reply, "look, do I pay you to think?"

humans, ya know? LOL

[Orrex]

19. No diving.

[OverBurn]

42. Trump University?

[Orrex]

20. Sounds like you've been promoted to "veal"

[Javaman]

12. outside that cube is an alternative universe. ;) nt

[SouthernDemLinda]

43. Nothing then, when described as an infinite void, excludes all possibility of anything else existing

Time came into existence at the Big Bang. At the Big Bang (time is zero) and (mass had to be zero) the singularity had to be mass less. If there is no time beyond Planck time (smallest amount of time possible) mass does not exist. If space did not exist in singularity and mass was not the origin of the universe we have to consider its energy equivalent as the initiator.

Time and space had a finite beginning that corresponded to the origin of matter and energy. The Big Bang was the expansion of everything and enormous energy was the initiator. With quantum mechanics things happen spontaneously.

Gravity makes it possible for the universe to spontaneously come into existence, as a necessary outcome of the way physics operates.

Prior to the singularity, nothing existed, not space, time, matter, or energy - nothing. There is no space outside of the universe; there is no "nothingness" that the universe exists inside of. Everything is inside the singularity. We are inside the singularity. The universe is completely self-contained and not affected by anything outside itself.

The universe has no boundaries because a boundary would place a limit on the size of nothingness, and indicate that there was something existing on the "other side" of the boundary, separate from the boundary itself. This would contradict the definition of infinite and nothing. This also excludes anything existing in any other dimension, or dimensions, as a dimension would then be a boundary.

Nothing then, when described as an infinite void, excludes all possibility of anything else existing, anywhere.

[Javaman]

44. um, okay, I was...just making a, um, joke...

[SouthernDemLinda]

48. Well, um, excuse me while I laugh my ass off!

HaAaaaaaaaaaaaaAa

[Javaman]

49. well, okay then...

>completely perplexed<

[alfredo]

4. They gave a figure of 93 billion light years.

"Today we are fairly confident that the Milky Way is probably about 100,000 light years across. The observable Universe is, of course, much larger. According to current thinking it is about 93 billion light years in diameter. How can we be so sure? And how did we ever come up with such measurements from right here on Earth?"

They need to define "it" in the third sentence.

[Android3.14]

23. Big difference (possibly an infinitely big difference) between

observable universe and the universe.

[alfredo]

28. Using "it" is lazy.

[pokerfan]

41. And reconciling that size with an age of 13.8 billion years

is left as an exercise for the reader.

[SouthernDemLinda]

45. My answere is not about the size of universe it's about the age.

They can estimate the age of the universe by various methods. One method is to use the fact that the universe has always been expanding and it is actually accelerating. To determine the age of the universe they estimate what the expansion rate might have been and translate that into a function of time. This is only an estimate because nobody knows the rate of expansion every second of the past. There is more than one method to estimate the age of the universe and about 13.7 billion yrs. is what most models estimate. The Earth is about 4 billion yrs. old.

,,,,,,,and Genesis 1:1 claims that "in the beginning" God created the Earth. We know that the Earth could not have formed before the sun.

[SouthernDemLinda]

46. Observation of the redshift-distance relationship.

Hubble's observation of the redshift-distance relationship. This relationship enables us to approximate the age of the universe with the help of three separate celestial bodies that all arrive at the same relative result. Hubble used what is known as "standard candles" to build a "cosmic distance ladder." By knowing the distance of certain celestial bodies he would be able to incrementally construct an age for the Universe. These standard candles were: Cepheid variables in neighborhood galaxies; bright stars in more distant galaxies and in galaxies millions of parsecs away, the brightness of the galaxy itself was used as a standard candle.

[valerief]

30. The headline must be a politician. nt

[Android3.14]

31. .

[Helen Borg]

5. Really?

That makes NO sense whatsoever. Here is why. For what we know, our universe is just the little speck of dust I see floating in front of me when the sun hits my window. Could somebody in that grain of sand know how big the "real" universe is? Perhaps they could measure the size of my room, if they have developed some sophisticated tools. How about what's outside my room? But more likely they'll just think their grain of dust is "the universe".

[A Simple Game]

10. I used to love physics and the study of the universe. A few years ago I came to the same

conclusion that you have and now think most of the theories in physics are laughable. The Earth could just be the universe's equivalent of what we call an atom or a dust mote and the Milky Way no more than a complex molecule or a dust bunny. No one in physics seems to have any ideas about perspective or scale.

[alfredo]

29. Please pass the bong.

What gets me is that solid is an illusion. Scale determines reality.

[WheelWalker]

38. Horton Hears a Who

[pokerfan]

40. This is too much!

[InAbLuEsTaTe]

7. The human mind cannot truly comprehend the vastness of the Universe.

[Fla Dem]

9. The universe is is constantly expanding.

[SCantiGOP]

11. Milky Way "exceptional"

We have to have galactic exceptionalism to go along with our American exceptionalism.

[sarge43]

14. Yeah. What universe?

The one we are able to detect or the actual one?

[Bradical79]

16. Article talks about both

But the headline is inaccurate. It talks about clever measurment techniques used in a model that may be more accurate. But it also bluntly undermines the headline towards the end when the author writes that we really have no idea, lol.

[Bradical79]

15. Interesting article, click bait headline though :-P -nt

[packman]

22. A good video on the solar system, leap years, the calender and such cosmic things

?t=829

[Android3.14]

24. No-no-no-no

This is one of the most misleading graphics on the web.

[packman]

25. I've read that disclaimer - BUT

view the video, the guy presents it so that it REALLY,REALLY makes sense - about 18/19 min. in. Just shows the earth spinning around the sun in another perspective. I'm of a scientific bend, love science and all things about science and the earth, sun spin on a cosmic trip viewed as a helix wrap-around seems logical.

[soilopen]

26. So what is there Beyond The Border

Of the universe

[Spitfire of ATJ]

32. Mexicans.

(according to Trump supporters)

[Xipe Totec]

36. ...

[SouthernDemLinda]

47. No boundaries.

We have observations that say that the radius of curvature of the Universe is bigger than 70 billion light years. Everything that we measure is within the Universe, and we see no edge or boundary or center of expansion. So, we can't see that there is anything that the Universe could be expanding into. The point is that there is nothing outside the Universe. The Universe has no boundaries.

Carl Sagan said, "The Cosmos is all that is, or ever was, or ever will be".

[allan01]

27. computer; end program.

[shadowmayor]

33. On the back of a Turtle

I thought we were riding on a disc, supported by 4 giant elephants standing on the back of a turtle who was swimming through the stars?

[nikto]

34. Shape of the universe?

Pick one ...


?1390327569?interpolation=lanczos-none&downsize=640







????????????????

[Gore1FL]

37. Spherical, likely.

The top two pictures represent spheres. (The WMAP is a representation of time-- take a slice and spin it around into a 3-d object and you'll get an idea of the universe at that point.)

I am pretty sure it isn't a cube.

[nikto]

39. But what about cheese? Does it have cheese on it?

[Xipe Totec]

35. It's Yuge! nt