Thread: Does This Universe Have ~200 Billion Galaxies?

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Does This Universe Have ~200 Billion Galaxies?

A few years back, data from Hubble led astronomers/cosmologists to conclude that their estimate of "200 billion galaxies in the Universe" was only 1/10 of the actual number of 2 billion. After the New Horizons spacecraft recently sent back data from past Pluto that contradicts Hubble, have researchers gone back to their 200 billion galaxies estimate? This number is very important! It would coincide with the estimate of 200 billion stars in the Milky Way.

\sqrt{17.4} = 4.17

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The uncertainties on both of these measurements are too big to make any call about whether they are equal, which wouldn't be a particularly important coincidence if it were true as the number of both 'stars' and 'galaxies' can vary depending on the threshold for inclusion you set on objects.

Our estimates are uncertain because they both involve assumptions about the distribution of types of object we are seeing. We then infer the number, using this assumption, from indirect measurements. Last I'd seen the estimate for the number of galaxies was back to 100s of billions (in the observable universe, not the whole universe, as we don't know how big the universe is).

3. It's like when a contractor tells you your concrete patio will be ready in "two weeks", or when someone says fusion power will be practical "in thirty years". There's no coincidence involved, just common estimates. Likewise, "200 billion" makes a nice round number to give the science journalists.

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We don’t know, as we have only analysed a tiny tiny proportion of it.

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Originally Posted by Galileo Galilei
A few years back, data from Hubble led astronomers/cosmologists to conclude that their estimate of "200 billion galaxies in the Universe" was only 1/10 of the actual number of 2 billion. After the New Horizons spacecraft recently sent back data from past Pluto that contradicts Hubble, have researchers gone back to their 200 billion galaxies estimate? This number is very important! It would coincide with the estimate of 200 billion stars in the Milky Way.

\sqrt{17.4} = 4.17
But, I have seen recent estimates for the number of stars in the Milky Way that range from 100b to 400b, such as:
https://www.esa.int/Science_Explorat...alaxies%20also!
https://en.wikipedia.org/wiki/Milky_Way

Numerical coincidences between unrelated things are meaningless, and even more so if the numbers don't agree.

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I think some of the confusion is coming from people mixing up stars verses solar masses.

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Originally Posted by Galileo Galilei
A few years back, data from Hubble led astronomers/cosmologists to conclude that their estimate of "200 billion galaxies in the Universe" was only 1/10 of the actual number of 2 billion. After the New Horizons spacecraft recently sent back data from past Pluto that contradicts Hubble, have researchers gone back to their 200 billion galaxies estimate? This number is very important! It would coincide with the estimate of 200 billion stars in the Milky Way.
Hi Galileo Galilei. Some sources would be handy.
The Hubble Deep Field series of observations gave estimates of 125 billion galaxies in 1999, 225 billion galaxies in 2013 and 2 trillion galaxies in 2016 in the observable universe.
A new observation by New Horizons looked at a dark part of the sky and measured the light it saw: Deep Space Might Not Be Completely Dark, New Study Suggests. The Hubble results said that the total light would be ~4 times greater than the number of observed galaxies. New Horizons got 2 times the light in New Horizons Observations of the Cosmic Optical Background. The press release for the paper has a correction
Correction: A prior version of this release indicated that the New Horizons observations were inconsistent with an earlier study that estimated there are 2 trillion galaxies in the universe. The New Horizons observations do not place a constraint on the total number of galaxies but rather do constrain the total amount of light all galaxies emit in the ultraviolet-optical bandpass.
I emphasized observable because as far as we know the universe is much larger than the observable universe. The measured curvature of the universe is close to and includes zero.

8. Originally Posted by Galileo Galilei
This number is very important!
What would be the significance if they were similar in number?

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Shaula,

There Are No Coincidences. So, you're going with the estimate of 200 billion galaxies?

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Noclevername,

There Are No Coincidences. You didn't answer the question. Do you go with the estimate of 200 billion galaxies? If so, where are you getting that number from?

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cannongray,

You mean you don't know. We had a good estimate of "200 billion galaxies" for many years. The Hubble made an observation that got wrongly interreted to be 10x more - 2 trillion! The New Horizons has given us its view from the Kuiper Belt which conflicts with Hubble. So are we back to ~200 billion? I had a space writer tell me, "Our gang thinks it's ~400 billion galaxies". If that's the current estimate, I need to get it confirmed.

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Originally Posted by skysurfer5cva
But, I have seen recent estimates for the number of stars in the Milky Way that range from 100b to 400b, such as:
https://www.esa.int/Science_Explorat...alaxies%20also!
https://en.wikipedia.org/wiki/Milky_Way

Numerical coincidences between unrelated things are meaningless, and even more so if the numbers don't agree.
If numbers don't agree, there's no connection. There Are No Coincidences - there is interconnectedness. Good scientists are always trying to discover connections and patterns in Nature. "100-400 billion stars in the Milky Way" on Wikipedia is from 2012 & 2016. The estimate has certainly changed quite a bit in the last 5 years going to 2 trillion and now being corrected.

"For the Universe, the galaxies are our small representative volumes, and there are something like 10^11 to 10^12 stars in our Galaxy, and there are perhaps something like 10^11 or 10^12 galaxies." - https://www.esa.int/Science_Explorat...alaxies%20also

Huh. The ESA is making a connection between the number of stars in the Milky Way and the number of galaxies.

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Originally Posted by Bearded One
I think some of the confusion is coming from people mixing up stars verses solar masses.
Ok, but I've heard 200 billion stars in the Milky Way for years. I AM trying to pin down how many galixies there are in this Universe. Have you got a source/link for that?

14. Welcome to the CosmoQuest forums, Galileo Galilei.

The Space/Astronomy Questions and Answers forum is where people can get mainstream answers to their questions. Sometimes, those answers are "we don't know yet" or "we're not sure." Answers may not be argued on an against-the-mainstream (ATM) basis, nor may ATM claims be asserted here. Please read our rules, linked in my signature line below.

15. Originally Posted by Galileo Galilei
Ok, but I've heard 200 billion stars in the Milky Way for years. I AM trying to pin down how many galixies there are in this Universe. Have you got a source/link for that?
I don’t know how many galaxies or stars there are. There are estimates and we should note the “observable” word. However I take issue with your capitalised “ there are no coincidences” and “interconnectedness” in the context of your question. There is no mainstream view or even non mainstream suggestion that the number of stars in any one galaxy is connected to the number of galaxies. Both vary in size and stars form and die too. Is there a spooky reason for your question?

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Originally Posted by Galileo Galilei
Shaula,

There Are No Coincidences. So, you're going with the estimate of 200 billion galaxies?
Yes there are coincidences. A 2017 Odyssey weighs as much as an average giraffe, for example. Doesn't mean there is a connection.

I'm going with "there are a range of estimates and some upper and lower bounds, however these vary by the methods used and assumptions made to calculate them"

17. I'm mostly restating points made above by Shaula and Bearded One (among others). Something most of us are aware of, but might be new to our new member Galileo Galilei is that the actual number of stars in our galaxy is a number that hasn't been counted, but rather, estimated, and that estimate depends strongly on what is the lower limit of what you call a star and what is a large planet. I've seen realistic estimates that there are 500 billion stars in our galaxy. Most of them are less than 1/5 the mass of the Sun. Similarly, you can question what is a galaxy, and what is a collection of debris from a collision of galaxies (like the Magellanic Clouds). The actual number in our universe is a pretty flexible number. Also concerning the number of galaxies... you'd have to ask when do you measure, and how much of the universe do you count? Just the observable universe? Really, we don't know how many are in the entire universe. Once the James Webb Space Telescope starts looking in mid-IR bands, will the number of observable early galaxies suddenly shoot up? Seems likely.

18. Originally Posted by Galileo Galilei
Noclevername,

There Are No Coincidences. You didn't answer the question. Do you go with the estimate of 200 billion galaxies? If so, where are you getting that number from?

And yes, there certainly are coincidences in life, especially when dealing with rough estimates that have extremely wide error bars, as in this situation. Two vague numbers that are approximately similar but unrelated, have no significance.

19. Originally Posted by Galileo Galilei
If numbers don't agree, there's no connection. There Are No Coincidences - there is interconnectedness. Good scientists are always trying to discover connections and patterns in Nature. "100-400 billion stars in the Milky Way" on Wikipedia is from 2012 & 2016. The estimate has certainly changed quite a bit in the last 5 years going to 2 trillion and now being corrected.

"For the Universe, the galaxies are our small representative volumes, and there are something like 10^11 to 10^12 stars in our Galaxy, and there are perhaps something like 10^11 or 10^12 galaxies." - https://www.esa.int/Science_Explorat...alaxies%20also

Huh. The ESA is making a connection between the number of stars in the Milky Way and the number of galaxies.
They are? It seems to me they are just giving ballpark figures. You shouldn’t read too much into it. Do you understand that the Milky Way is neither anywhere near the largest or smallest galaxy? Do you understand that we don’t have tight estimates for either the number of galaxies in the observable universe or the number of stars in our galaxy? Numbers tend to change with time and observation methods. Small stars can be notoriously hard to detect, it’s easier to determine the mass (within rough boundaries) of the galaxy and estimate the number of stars from that, but there are issues doing those estimates.

Also, when discussing the number of galaxies do you understand we are talking about, at best, the observable universe? The rest of the universe is expected to be much larger at least, and possibly infinite.

Like others here I don’t agree that there are no coincidences. Just for example, consider the apparent size of the Moon versus the sun as seen from the surface of the Earth, that can give us nice eclipses. It is not unique to Earth, it changes over time as the distance between Earth and Moon change, but for now at this point in Earth’s history, it is something we observe.

In comparing the number of galaxies and stars in our galaxy, they are rough order of magnitude estimates that shouldn’t be taken too seriously.

20. I remember I once asked how fast the sun's radius was increasing as it expands. Someone calculated the answer, and I commented (partially as a mnemonic) that it was the same rate as crustal plates move or fingernails grow. Somebody jumped on me for promoting woowoo stuff.

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PetersCreek,

You didn't answer the question. After a couple days of google searches, the latest estimates of the number of galaxies in this Universe is 400 billion and the number of stars in the Milky Way is 400 billion. 'Coincidence'?

https://www.cnn.com/2021/01/13/world...rnd/index.html
https://www.cnn.com/2021/03/17/world...scn/index.html

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Originally Posted by profloater
I don’t know how many galaxies or stars there are. There are estimates and we should note the “observable” word. However I take issue with your capitalised “ there are no coincidences” and “interconnectedness” in the context of your question. There is no mainstream view or even non mainstream suggestion that the number of stars in any one galaxy is connected to the number of galaxies. Both vary in size and stars form and die too. Is there a spooky reason for your question?
Current estimates are 400 billion galaxies and 400 billion stars in the Milky Way. Of course, they're not all directly observed. A good scientist is always looking for connections and patterns.

As an interdisciplinary scientist, I've discovered through 30 years of extensive study of chaos theory and other fields that There Are No Coincidences - there is synchronism, interconnectedness, nonlocality, retrocausality, subconscious telepathy, design-and-alignment, signs from GOD and consequences. That's the title of my 74-page booklet that satisfies the prophecies of Revelation 5:1. See link redacted.

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Originally Posted by Shaula
Yes there are coincidences. A 2017 Odyssey weighs as much as an average giraffe, for example. Doesn't mean there is a connection.
Wrong, there's obviously a connection - the 2017 Odyssey and the avg. giraffe weigh the same. Have you got a link/source for that factoid? Do you know whether the designer of the '17 Odyssey intentionally designed the car to weigh the same as an avg. (male?) giraffe? If you don't know, just say, "I don't know."

I'm going with "there are a range of estimates and some upper and lower bounds, however these vary by the methods used and assumptions made to calculate them"
That's a non-answer. 400 billion galaxies and 400 b stars in Milky Way are the current estimates.

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Originally Posted by Galileo Galilei
A few years back, data from Hubble led astronomers/cosmologists to conclude that their estimate of "200 billion galaxies in the Universe" was only 1/10 of the actual number of 2 billion. After the New Horizons spacecraft recently sent back data from past Pluto that contradicts Hubble, have researchers gone back to their 200 billion galaxies estimate? This number is very important! It would coincide with the estimate of 200 billion stars in the Milky Way.

\sqrt{17.4} = 4.17
The 200 Billion stars and galaxies makes no sense. Where are solar systems taken into account?

25. Originally Posted by Galileo Galilei
Current estimates are 400 billion galaxies and 400 billion stars in the Milky Way. Of course, they're not all directly observed. A good scientist is always looking for connections and patterns.

As an interdisciplinary scientist, I've discovered through 30 years of extensive study of chaos theory and other fields that There Are No Coincidences - there is synchronism, interconnectedness, nonlocality, retrocausality, subconscious telepathy, design-and-alignment, signs from GOD and consequences. That's the title of my 74-page booklet that satisfies the prophecies of Revelation 5:1. See link redacted.

GG
This is Q&A where mainstream scientfic answers are given, not G_O_D ATM numerology speculations.
Refrain from posting this, otherswise further infractions will be given.

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Originally Posted by Galileo Galilei
Wrong, there's obviously a connection - the 2017 Odyssey and the avg. giraffe weigh the same. Have you got a link/source for that factoid? Do you know whether the designer of the '17 Odyssey intentionally designed the car to weigh the same as an avg. (male?) giraffe? If you don't know, just say, "I don't know."
... Wow. My reference is that I searched for average animal weights, then for car weights. Then I went through the lists until I found a close match. One person didn't design the Odyssey and the design process at Honda doesn't allow this kind of design choice to drive it. Nice attempt to shift the burden of proof, by the way. If you are claiming they are related, you need to prove that they are because the simpler, more parsimonious, explanation is that they are not. Lets throw some other ones out there in an attempt to show how indefensible this stance that there are no coincidences are:
- My business card is precisely as long as my coffee mug is wide
- The sum of my phone width and height is the same as my laptop's depth
- I have a drinking cup that is exactly the same width as my hand with the thumb tucked in (and a drinking cup stuck on my hand right now)

I could go on but I need to go get a cup off my hand.

Originally Posted by Galileo Galilei
That's a non-answer. 400 billion galaxies and 400 b stars in Milky Way are the current estimates.
It is a realistic answer. No one has counted either of these figures so they vary by the assumptions made to estimate them.

27. Galileo Galilei, I had questions for you too. I guess you missed them? See here:

https://forum.cosmoquest.org/showthr...53#post2539853

Anyway, I see now that this involves some sort of religious claim of yours. Even if it were allowed here, I have no interest in discussing your religious beliefs. Believe what you want, but I’m interested in science discussions, not discussions/debates on faith based beliefs.

28. Thread closed pending moderator discussion.