Universe Is Lonelier Than Imagined, New Estimate Suggests

A model has just revealed that our previous estimates about the number of galaxies in the universe was probably way too optimistic.

Original estimates placed the number somewhere between 170 billions and 500 billions.

According to the newer estimate, the number would actually be 10 to 100 times smaller.

"Earlier estimates placed the number of faint galaxies in the early universe to be hundreds or thousands of times larger than the few bright galaxies that we can actually see with the Hubble Space Telescope. We now think that number could be closer to ten times larger."

source

The new estimate has been obtained using computer simulations to model the most probable population of galaxies in both the observed and the unobserved universe. The model fits the distribution of known galaxies. And if it happens to be right, then the universe is actually a much lonelier place than previously imagined.

But this is of course no more than an estimate, an estimate which is about to be put to the test:

These results will be tested further when the much-anticipated James Webb Space Telescope comes online in late 2018

Given the foam-like structure of the universe, with large areas of intergalactic nothingness, I am not surprised to see the estimate getting revised to a more conservative number.

This is one of many reasons that many more Deep Field projects should be assigned to the Hubble telescope, they should be doing at least one or two Deep Field pictures a month to survey different areas of the sky.

Even if there were only 17 billion Galaxies (ten times less) given that our galaxy is average in size containing around 400 billion stars... that would mean there is around 6.8e+21 stars in the known universe...

That is around 68000000000000000000000 stars.....

It seems far too small a number to me....

I think they have something wrong.

a reply to: Korg Trinity

You mean that 6.8 sextillions (6.8 billion trillions) stars is too small for your taste?

All this squeezed inside a 13 billion years time frame? That's an average of about 5 trillions stars being born each years ever since the start of the Universe.

originally posted by: swanne
A model has just revealed that our previous estimates about the number of galaxies in the universe was probably way too optimistic.

And what about the other universes? Why should we assume there is just one or that be can even consider how big ours even is?

These kind of definitions are continually evolving so trying to pinpoint a statistic that is always changing just seems like more funding for the "scientist say" brigade.

a reply to: swanne

Wouldn't an estimate of the number of stars in the galaxy, based upon density, be highly dependent upon where the boundary lies?

If the universe was spatially large, approaching the infinite, then the number of galaxies would also approach the infinite.

Can we say with any certainty the size of the universe as by now there should be much of it beyond our light cone (assuming the Hubble constant is showing an expanding universe) and therefore the outer bounds are beyond our reach to see.

Still it is refreshing to see a more rational and finite universe. Infinities are mathematically inelegant, observationally unknowable, instrumentally immeasurable and pose more questions than they answer.

originally posted by: nerbot

originally posted by: swanne
A model has just revealed that our previous estimates about the number of galaxies in the universe was probably way too optimistic.

And what about the other universes? Why should we assume there is just one or that be can even consider how big ours even is?

Sure -- we can speculate on the possibility of other universes, but we can't assume there are other universes without having good evidence to back up that assumption.

They are trying to make an estimate of the scope of the universe based on the number galaxies that are visible to us, not making a sweeping claims on the possibility of a multi-universe based on hypothetical mathematical models.

These kind of definitions are continually evolving so trying to pinpoint a statistic that is always changing just seems like more funding for the "scientist say" brigade.

Wouldn't scientists assuming that there are other universes without having good evidence to back up that claim be an example of the "scientists say brigade"?

...e.g., "Scientists say there are other universes, although they do not yet have good evidence to prove it."

a reply to: swanne

Of course there is the possibility that in the eternal infinity of space our collection of galaxies may be just one cluster. There could be big bangs happening through the whole of infinity at different times creating many clusters of galaxies. It seems rather odd that in the whole of eternal space there would be only one big bang and matter centralised to one speck of eternity. Who knows, may be matter is dispersed in many regions of space. Q would be a good person to ask about this.

Have these people seen the deep field photo? Go take a look at it, and then realize that it's only a FRACTION of what the telescope can focus on. It would take 1000's of years for that telescope to map the universe from it's view point, imagine how many galaxies it would turn up.

originally posted by: Soylent Green Is People
Sure -- we can speculate on the possibility of other universes, but we can't assume there are other universes without having good evidence to back up that assumption.

And the evidence is everywhere....

Everything is made up of something smaller and part of something bigger. Why shouldn't we speculate on the possibility that our universe is no different than an atom, or a person, or a planet etc depending purely on the perspective point of view. Why should a universe follow different rules when it is part of things that follow a "universal" norm?

Pocket Universe.

originally posted by: nerbot

originally posted by: swanne
A model has just revealed that our previous estimates about the number of galaxies in the universe was probably way too optimistic.

And what about the other universes? Why should we assume there is just one or that be can even consider how big ours even is?

These kind of definitions are continually evolving so trying to pinpoint a statistic that is always changing just seems like more funding for the "scientist say" brigade.

I believe you have an outdated view of universes . Per current popular models , we exist in one universe in the multiverse. The universes are separated from each other by the multiple dimensions. Therefore we cannot interact (at least not yet) with any of the others. In fact ,one model shows all the universes coexist together . Therefore you may have a Tyrannosaurus Rex right beside you now. The infinite universe is not infinite. What lies outside , space , may well be. The universe is constantly expanding into that empty "space" . The "pictures" that x-ray , etc. that deep space telescopes take actually are pictures of that part of the universe millions of years ago. The further they look , the further back in time it goes.Since the universe is expanding , the distance between galaxies is ever growing.And galaxies do collide and form one larger galaxy . The same may happen to ours in the very distant future.So the number of galaxies may get smaller and the distance between them greater.

originally posted by: Aleister
This is one of many reasons that many more Deep Field projects should be assigned to the Hubble telescope, they should be doing at least one or two Deep Field pictures a month to survey different areas of the sky.

They kind of do. Check out my Hubble Highlights videos, there are many more "deep field" pictures taken by Hubble than you know.
www.youtube.com...

a reply to: swanne

But how many per second?

a reply to: ngchunter

Not too many, according to the Wikipedia articles on the Deep Fields. If I ran the Hubble I'd devote an entire year to Deep Fields.

originally posted by: Aleister
a reply to: ngchunter

Not too many, according to the Wikipedia articles on the Deep Fields. If I ran the Hubble I'd devote an entire year to Deep Fields.

The deep field images cover only a very tiny portion of sky. The first one was about One 24-millionth of the sky and the second one was about one 13-millionth of the sky.

It would be cool if they could map the entire sky with deep field images, but considering each deep field image takes about 10 days of observation time, it would take Hubble about 500,000 years to survey the entire sky in that manner.

a reply to: swanne

Ya, it says in the first quote it could be ten times larger...

If aliens have mastered inter stellar and inter galactic space travel then it won't be any lonlier at all.
In fact it would be busier.

That's if we're rolling with the "aliens don't exist and have never existed to the extent of our knowledge" statement from the white house.

originally posted by: swanne
a reply to: Korg Trinity

You mean that 6.8 sextillions (6.8 billion trillions) stars is too small for your taste?

All this squeezed inside a 13 billion years time frame? That's an average of about 5 trillions stars being born each years ever since the start of the Universe.

Something sounds wrong there.

originally posted by: nerbot

originally posted by: Soylent Green Is People
Sure -- we can speculate on the possibility of other universes, but we can't assume there are other universes without having good evidence to back up that assumption.

And the evidence is everywhere....

Everything is made up of something smaller and part of something bigger. Why shouldn't we speculate on the possibility that our universe is no different than an atom, or a person, or a planet etc depending purely on the perspective point of view. Why should a universe follow different rules when it is part of things that follow a "universal" norm?

Pocket Universe.

There is plenty of scientific speculation about the possibility of other universes -- i.e., that our universe is only a part of a multiverse.

I mean, where do you think the idea of other universes came from in the first place? It came from scientific speculation.


However, the point of the estimate in the OP was not about speculation about what possibly could be the true nature of the universe, but rather an estimate of the number of galaxies using hard data gathered through observation.

Now let me think? An estimate is neither high nor low but in between but the bottom line is they don't know.
Now suggest, that means might or might not ie. they don't know. Now in my opinion 2 don't knows means totally nothing and just tells me that they are guessing. Are they making a noise to try to justify some more funding as you have to show something for years of sitting on your backside thinking.

a reply to: Soylent Green Is People

A year of ten-day Deep Fields, set in different parts of the sky, would give the human race 37 more Deep Fields. Well worth the effort and the telescope time. A year and then it can return to other projects. Is it feasible? Probably. The Hubble team just has to call it a project and dedicate itself to it. With 37 more of the things a better approximation of the entire sky can be ascertained, and it may also uncover some surprises and semi-rarities.

EDIT: Here's the Wikipedia list of the nine Deep Fields done so far:
en.wikipedia.org...