The Universe is 13.7 billion years old.
About five billion years ago, an energy field that we call dark energy became important. Dark energy is a repulsive form of gravity, which means that the expansion of the universe isn’t slowing down, it’s accelerating.
After 9 billion years of the expansion of space slowing down, it’s now speeding up.
The Cosmic Background Radiation from the birth of the universe that we are seeing now originated when the universe was a sphere with a 42 million light year radius.
However that light took 13.7 billion years to reach the earth because of a rapidly expanding universe.
We can currently see objects 46 billion light years away but we see them as they were in the distant past.
We will never see the light from objects that are currently more than 15 billion light years away, because the universe is still expanding.
We are losing 20,000 stars every second to an area that will forever remain beyond our future view.
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
Known for identifying cutting edge technologies, he is currently a Co-Founder of a startup and fundraiser for high potential early-stage companies. He is the Head of Research for Allocations for deep technology investments and an Angel Investor at Space Angels.
A frequent speaker at corporations, he has been a TEDx speaker, a Singularity University speaker and guest at numerous interviews for radio and podcasts. He is open to public speaking and advising engagements.
47 thoughts on “The Universe is 14 Billion Years Old But Visible Universe is 92 Billion Light Years Wide”
This is the first explanation I could understand. Light from a source at the “edge” of the universe when its radius was only 42 million light years is now 46 billion light years away. And it took 13.7 billion years to reach us due to the expansion of space.
Jamie m-[ade me do this
Bollocks that’s what this theory will be in the future
What a load of nonsense, literally, non-sense
The universe seems to have a finite age so I believe for this to be so it must also have a finite size.
If you walk in a straight line in any direction where is your destination? Your starting point. The ‘2d’ surface of our 3d planet is actually curved – you don’t fall off the edge of the planet when your ship goes over the horizon – the straight line is actually a circle and ‘walking’ in a straight line brings you right back where started.
If you radiate outward in all directions where is your destination? Your starting point. From within (inside) your starting point. The ‘3d’ volume of our 4d space is actually a ‘circle’ (inside out hyper torous). The stars you are ‘losing’ are the ‘ships’ going over the hyper horizon.
When you understand this fact then you will comprehend what that ‘expanding’ universe, and gravitational decompressional redshift actually is. You will also understand exactly what entanglement is and that gravity and vacuum energy explains all forces, protons, electrons, orbitals and electromagnetism and finally be at the starting point for universal navigation. You will also understand that dark matter/energy is just another two orders inserted into a flawed curve fit equation of bs piled on bs made by mathematical fraudsters hiding out as physicists to ensure job security via hyper complexity non-sense.
So, effectively, at greater than 15 billion lights years distance from each other, objects recede from each other faster than the speed of light, due to expansion of space. It’s like two people running towards each other, but they are on walkways that carry them away from each other, faster than they can run towards each other. Maybe?
No, because, as far as I understood, the expansion of the universe is taking place at a very large level: the level of super-clusters. In other words, the super-clusters are moving away from each other, within each super-cluster the galaxies are bound by gravity and actually even gradually merging.
If space-time is expanding at an increasing rate, shouldn’t we be able to measure an ever greater distance between the Earth and the Moon? Is any one checking this? Also you should read NBF’s recent article on Super Luminal communication by Advanced Civilizations.
Can 92 billion light years wide be measured in picobarns?
What is an evidence for targeted individuals? What is being said as another way discernment and explication anent these miracle technologies of mind and matter?
How is this a contrast between making sense of earth’s physical geometry, determinate and the intuition of self, principle of discontinuity, evolution of the earth’s surface? (ORDER&CHAOS)
Praxis for the changes of the earth can be mapped, making Edward Snowden’s revelations to the accelerating systems artificial intelligence…apparently, more information about Superconducting Cosmic Strings could be helpful for Tump to figure out what nine mouthpieces on both sides of his head. . . are saying! Gödel’s Incompleteness Theorem – Numberphile
Where is the mass inside a black hole?
It’s not so much that the stars are accelerating. Rather, the space between them is expanding, and the expansion rate is increasing. There’s no “opposite” direction either – you’ll see the same thing no matter where you look from.
To visualize that, draw a bunch of dots in photoshop or paint. Copy them, and scale up the copy a little (just 5-10% bigger). Then try to align one of the dots in the scaled copy with the original. You’ll see that the dots near it have shifted by a little bit, and the dots further away have shifted more, and it looks like all the dots shifted away from the aligned dot.
That aligned dot is the observer. Now try aligning a different dot.
> Are we limited in what we can see because of the superluminal expansion of space or because the age of the universe is too young for the distant light to have reached us?
Both. Though I think at the moment, the age of the universe is the bigger limiting factor.
The furthest we can see with light is the time when the universe cooled down enough for protons and electrons to combine to form neutral hydrogen. That time appears to us as the cosmic microwave background. Earlier than that, the free electrons would scatter the light, so it’s like trying to look through an opaque window.
But also, we can’t see the very very early objects after hydrogen formation (such as early gas clouds), because our telescopes aren’t powerful enough. The background is easier to see because it’s everywhere.
Maybe. But I doubt that we’ve reached those kind of red-shifts yet. Remember that the cosmic background, the oldest detectable light, is still in the microwave part of the spectrum. It didn’t even red-shift to radio yet.
I meant that to be read together as “between them and us”. In the denser regions, gravity holds things together, though I’m not sure by which mechanism: does it slow down the expansion of space itself, so that it expands less in denser regions, or does it produce a counter-motion of the bodies through space (kind of like an anchored boat resisting the flow of a river)? Perhaps its a combination of both. Or perhaps those two options are equivalent (less likely, I think). Those kind of details are beyond my level.
Another factor to keep in mind is that at smaller scales the expansion is less noticeable, even if it’s uniform: if you multiply 1 million by 2, you get a difference of 1 million; but if you multiply 1 by 2, you only get a difference of 1. The scale difference in space is even larger than that: billions of light years to the distant galaxies, tens of thousands of light years between stars within a galaxy (a factor of 100000), and only fractions of a light year within a solar system (another factor of 100000, or even more for the planetary portion: the furthest point of Pluto’s orbit is just ~1/1000th of a light year from the Sun).
Finally, “expanding faster than light” is rather a misnomer. It doesn’t have a linear speed. It’s more of a stretch rate. The expansion causes galaxies to appear to be moving away. The more distant ones appear to recede faster, and the most distant ones can appear to recede faster than the speed of light.
How does the Verlinde theory of entropic gravity jibe with accelerating expansion? I assume things that drop over the horizon remain entangled with things in the light cone. Is dark energy the analog to Hawking radiation in entanglement-based spacetime?
My intuition from watching lots of Susskind lectures is that this is an incorrect statement. The outside observer should never lose sight of an object going over a horizon. I think what this is saying is something like “the photons from 20000 stars is red shifted to such low energy that the positional uncertainty of observation is larger than the visible universe.” Imagine the light cone is a giant Casimir bubble, eventually you will red shift enough so your wavelengths are excluded.
I read your comment, then I went to the gym.
I had a 15 kg weight equivalent rubber band snap on me as I reached full tension and if the gym hadn’t been cold enough to need a football jersey I could have been quite hurt. Especially if I’d dropped the other 100kg.
You have a power. Use it wisely.
If the stars are accelerating, would we also be accelerating along with them? Could it be that we are moving in an opposite direction? Curious?
This is all way beyond my pay grade. Are we limited in what we can see because of the superluminal expansion of space or because the age of the universe is too young for the distant light to have reached us? I always though the big bang argument was that if we look back far enough and we don’t see stars and galaxies but we see blobs of gas or other more primitive stuff then we know we’ve seen back almost to the big bang. But what we see is just more galaxies and stars moving at ludicrous speed, right? Forgive me I don’t even know if my ramblings make any sense. I’m going to find an ice pack and apply it to my forehead.
There are some estimates about the true size of the Universe, but those are just… estimates. One can be found here 10^10^10^122 megaparsecs https://en.wikipedia.org/wiki/Universe#Size_and_regions
I think rather that Physics has “called it” on that: spacetime is at that one exquisite balance-point between being negatively curved (a hyper-saddle) and positively (a elliptical ovoid), and instead is flat. No curvature.
Seems backed by everything so far measured in astrophysics, and down to the subatomic scales.
The other thing to recall is that although we can say with remarkable certainty and precision that the electromagnetically ‘visible’ (or inferable) Universe is some 13.7 billion YEARS old, and that its most rare furthest visual galaxies are within 95% of that apparent astrophysical distance, we also can say that that is only the sphere of time within which we can see outward, from where we are.
We simply HAVE NO COMPELLING IDEA how truly ‘big’ the Universe might well be. We don’t. Sad, but true. I bolded that to get across the fiction of certainty that one often runs into when reading similar article snippets. It ain’t certain at all.
If space between us is travelling faster than light speed for 8B years why is our own solar system exactly the same as ~2000 years ago, surely dark energy would have ripped it apart
The space between everything is increasing. At astronomically large distances you have correspondingly vast amount of combined increases in space between everything. Even though the amount of increasing space between any two things is not much, multiplied by the number of things in astronomically large distances, you get effectively more expansion of space than the fixed limit of light speed.
So the speed of light is incredibly high, but it is fixed and thus is eventually caught up to and passed by a sufficiently large amount of space’s expansion.
To phrase these more clearly:
No. The furthest stars were ~14 billion ly ~14 billion years ago. They’re a lot further now. There’s also nothing preventing faster-than-light expansion. Only motion through space can’t exceed the speed of light. See my other posts for more details.
(Also, the current distance to the farthest stars is believed to be 46 billion ly, not 90. ~90 is the total diameter if you add both opposite directions, i.e 46 * 2.)
If inflation did indeed occur as current theory suggests, it happened and ended far earlier than the first stars formed. So it’s not very relevant. However, current data also suggests that the universe’s expansion is accelerating. This is a good illustration:
you forgot the rubber band constant of the universe… if space time is a giant 15 billion year old ball of rubber bands expanding until the rubber band exceed theirmaximum stretch… ouch…
Because they’re not actually moving through space (at least not in an amount that’s relevant to this discussion), but rather, the space between them (and us) is expanding.
If you refer back to the example in my first post, over some period of time, as a result of the universe expansion, star A receded by 1 million ly, and star B receded by 2 million ly in the same time portion. But I didn’t specify how long that took. Suppose that expansion took less than 2 million years – then the apparent velocity of star B would be greater than the speed of light. But it’s actual motion through space could’ve been much smaller.
On the other hand, the light itself always propagates through space, so it moves at the speed of light.
title violates laws of physics… if universe is only 15billion years old then that means the farthest apart any two stars could be is 30 billion light years… even if two star are traveling in opposite directions at the speed of light…that’s only 15+15=30 billion light years, not 90 billion light years!
There are some estimates, look for example here https://en.wikipedia.org/wiki/Universe#Size_and_regions (last sentence). But we really dont know for sure. So far the data implies that the universe if infinite. I personally dont like this idea. That would imply infinite stars, planets etc. and perhaps even infinite civilizations? But we wont be able to interact with most of them, ever.
No field responsible for cosmic inflation has been discovered. However such a field, if found in the future, would be scalar. The first similar scalar fieldproven to exist was only discovered in 2012 – 2013 and is still being researched. So it is not seen as problematic that a field responsible for cosmic inflation and the metric expansion of space has not yet been discovered.
The proposed field and its quanta (the subatomic particles related to it) have been named inflaton. If this field did not exist, scientists would have to propose a different explanation for all the observations that strongly suggest a metric expansion of space has occurred, and is still occurring much more slowly today
How can they recede faster than the light they emit travels towards us?
“We can currently see objects 46 billion light years away but we see them as they were in the distant past.
“We will never see the light from objects that are currently more than 15 billion light years away, because the universe is still expanding.”
Theses statements appear to be contradictory. How can we see objects that are 46 billion light years away if we can’t see objects that are more than 15 billion light years away.
Also, how fast is the universe expanding, and why doesn’t that violate the 186k mps speed limit?
There’s one other thing keep in mind:
The oldest light that we’re currently seeing (or can ever see) is light from near the birth of the universe. In other words, the light of the stars that were ~14 billion light years away ~14 billion years ago. If at that point the expansion was slow enough that those furthest stars were receding at less than the speed of light, then no stars could cross the edge of the observable universe at the time (the edge of the observable universe was and is receding at the speed of light).
In that case, we won’t be able to see such crossing at the moment, even if we had the most sensitive telescopes that physics would allow. However, we should be able to detect the reverse: new stars coming into view.
If at some later point the expansion accelerated such that the furthest observable stars started receding faster than the speed of light, and thus could cross this “event horizon” of the universe, then that crossing has or is or will occur at a much later time and at a much larger distance (since the observable universe has already expanded some by then). The light from those events hasn’t reached us yet.
Epicycles, that is all it is. A mathematical crutch to extend a theory that is broken and in need of a better explanation.
We could still be using the Ptolemaic system and Epicycles, but someone (Copernicus) had the good sense to put the sun at the center of the Solar System.
Theoretically yes, though at those kind of distances we’d be looking at whole galaxies, or even clusters of galaxies, rather than individual stars. The problem is that at those distances even whole galaxies appear so faint that you’d need to focus the telescope on them for a very long time just to collect enough photons to see anything at all (or you’d need to use a much larger telescope).
AFAIK, Hubble’s Ultra-Deep Field is the closest we’ve come so far to detect these oldest, furthest galaxies, but I’m pretty sure even those aren’t at the very edge of the observable universe. – https://en.wikipedia.org/wiki/Hubble_Ultra-Deep_Field
Its an illusion caused by the hypersphere curvature of the universe. The universe is closed and finite. At the end of the universe is the beginning of time. You cannot see past it.
What I would really like to know is an indication of the size of the entire universe (i.e. not just the observable). There are theoretical models based on cosmic inflation (e.g. by Guth and others) that conclude that the entire universe must be vastly larger than the observable one.
But no estimates based on direct observation and measurement of for instance the, any, curvature of the universe.
As far as I know.
Thanks Michael. So I bet this is something we could theoretically observe from Earth even now – a star crossing the edge, apparent relative velocity getting close to the speed of light, wavelenghts getting longer and finally the star is “gone” – it’s probably just our tools/sensors/methods not sensitive enough to detect such a faint signal.
Should be, yes.
So generally speaking, yes: stars will red-shift more and more as they move further away (and as a result, recede faster) until eventually they cross the edge of the observable universe (the above limit), and then after the last of their light reaches us, we won’t see them anymore.
Red-shift is proportional to velocity, and due to the expansion of the universe, velocity (and thus red-shift) becomes proportional to distance.
For example, suppose star A was 1 Mly (million lightyears) away, and star B was 2 Mly away. If the universe expands to twice the size, all distances double, so now star A is 2 Mly away, and star B is 4 Mly away. Which produces an apparent velocity of 2 – 1 = 1 Mly per time portion for star A, but 4 – 2 = 2 Mly per time portion for star B. So twice the distance translates to twice the velocity, and therefore twice the red-shift. It doesn’t matter where you look from – you’ll see the same effect.
There’s no upper limit on red-shift. The reason why we can’t see past a certain distance is two-fold:
First, stars that were too far away when they were born hadn’t had enough time for their light to reach us yet. The limit is related to the age of the universe: if the universe is X years old, we can only see stars that were up to X lightyears away back then. By now, those stars are much further away, due to the universe’s expansion.
This limit grows as the universe ages. But:
The second reason is that beyond a certain distance, the stars are moving away faster than the above limit can catch up. That’s why we’re “loosing” 20000 stars per second (currently).
If the expansion is speeding up wouldn’t 20,000 stars lost every second , keep increasing?
Not exactly news, but a good reminder for scientifically curious.
So how would that phenomenon look like from here hypothetically? The wavelenghts of those stars that are now passing the 15B LY line get longer and longer, so that with time all we ‘see’ is radio and then lower frequencies, until finally 15B years from now at a rate 20k per second those stars dissapear completely?
Is this something we’re observing now just the sphere size is different?
Comments are closed.