Is the universe actually expanding?

Question

Is the universe actually expanding or are we way off on that one? Just because we see red shift doen't mean that the microwave radiation is red shifted radiation from the formation of the univers. Surely it could be anything and this is all hypothetical?

Answer 1

maybe???Nobody knows for sure!

Answer 2

Everything we can see or sense about the rest of the universe shows that it is expanding at the current time. The microwave radiation is not red shifted (it is short so would be blue shifted) but is considered to be radiation from the start of expansion. We do not have pictures of the beginning, but the further out we look the more primitive events we see/sense.
Among the questions astronomers have asked is whether there is enough mass in the universe to stop the expansion and pull everything back together. The current answer is no.

Answer 3

The cosmic microwave background radiation you mention isn't the yard stick used to determine universal expansion. That's the red shift exhibited by light from stars in extremely distant galaxies. The red shift is a valid yard stick, therefore the measured recession of distant structures is valid. Since those structures---and every 'thing' else in the universe---is embedded in space then it follows that the space of the universe is expanding.

Answer 4

Yes, it's still a theory - just like big bang and relativity are still just theories. But the idea that the universe is expanding does seem to fit with all current known laws of physics, so it's generally assumed to be a fact.

But the red shift you mention is a pretty reliable indication of an expanding universe.

Answer 5

Most science about space is theory like the Big Bang. We speculate through data that the Universe is expanding. Here is an informative article that can explain the evidence to suggest why we think this.

Answer 6

The 1920s were important years in the development of modern astronomy. In 1922, the Russian physicist Alexandra Friedman produced computations showing that the structure of the universe was not static and that even a tiny impulse might be sufficient to cause the whole structure to expand or contract according to Einstein's Theory of Relativity. George Lemaitre was the first to recognize what Friedman's work meant. Based on these computations, the Belgian astronomer Lemaitre declared that the universe had a beginning and that it was expanding as a result of something that had triggered it. He also stated that the rate of radiation could be used as a measure of the aftermath of that "something".
The theoretical musings of these two scientists did not attract much attention and probably would have been ignored except for new observational evidence that rocked the scientific world in 1929. That year the American astronomer Edwin Hubble, working at the California Mount Wilson observatory, made one of the most important discoveries in the history of astronomy. Observing a number of stars through his huge telescope, he discovered that their light was shifted towards the red end of the spectrum and, crucially, that this shift was directly related to the distance of the stars from Earth. This discovery shook the very basis of the universe model held until then.

According to the recognized rules of physics, the spectra of light beams travelling towards the point of observation tend towards violet while the spectra of light beams moving away from the point of observation tend towards red. (Just like the fading of a train's whistle as it moves away from the observer) Hubble's observation showed that according to this law, the heavenly bodies were moving away from us. Before long, Hubble made another important discovery; The stars weren't just racing away from Earth; they were racing away from each other as well. The only conclusion that could be derived from a universe where everything moves away from everything else is that the universe constantly "expands".

Hubble had found observational evidence for something that George Lemaitre had "prophesized" a short while ago and one of the greatest minds of our age had recognized almost fifteen years earlier. In 1915, Albert Einstein had concluded that the universe could not be static because of calculations based on his recently-discovered theory of relativity (thus anticipating the conclusions of Friedman and Lemaitre).


Edwin Hubble discovered that the universe was expanding. Eventually he found evidence of the "the Big Bang", a cataclysmic event whose discovery forced scientists to abandon the notion of an infinite and eternal universe.

Shocked by his findings, Einstein added a "cosmological constant" to his equations in order to "make the answer come out right" because astronomers assured him that the universe was static and there was no other way to make his equations match such a model. Years later, Einstein was to admit that his cosmological constant was the biggest mistake of his career.

Hubble's discovery that the universe was expanding led to the emergence of another model that needed no fiddling around with to make the equations work right. If the universe was getting bigger as time advanced, going back in time meant that it was getting smaller; and if one went back far enough, everything would shrink and converge at a single point. The conclusion to be derived from this model was that at some time, all the matter in the universe was compacted in a single point-mass that had "zero volume" because of its immense gravitational force. Our universe came into being as the result of the explosion of this point-mass that had zero volume. This explosion has come to be called the "the Big Bang" and its existence has repeatedly been confirmed by observational evidence.

There was another truth that the Big Bang pointed to. To say that something has zero volume is tantamount to saying that it is "nothing". The whole universe was created from this "nothing". And furthermore this universe had a beginning, contrary to the view of materialism, which holds that "the universe has existed for eternity".

Answer 7

You are right. Einstein was wrong. Not a lot of people know this.
The red shift you mention is to do with galaxies moving away from us. He said that everything was relative, including light velocity. He got that wrong to because he was a simple man who could only think in train and lift speeds Never mind, we know better now! I am editing this now because of what the other people are saying. Listen - the universe is infinite (we can't imagine where it could end. But the planets stars and other stuff are not infinite - they can be counted!!

Answer 8

I too do not buy into this argument that the universe is expanding; that infers it is expanding from a central point as if by some grand design. It also means the expansion is towards nothing, filling up the void, in which case it will run out of steam. For all we know it could be a series of expansions, not just one and not just in a radial, outward direction.

Answer 9

no, it can't be from "anything", and it is not hypothetical. There is hard evidence to the expansion of the universe, and nothing that would prove it otherwise. There is no technique or technology to red-shift light as much as it was to create Microwave Background, and there are actual pictures of the 'early Universe" in the process of formation.

Answer 10

redshifted means that the frequency of the object is decreasing, so it means that it is moving away from us. and most of the objects in the universe are redshifted, so it means it is expanding. this started with the big bang theory, which says that the universe started of as a small dense hot ball of gas that expanded out. and the present universe came from that ball of gas.
but also scientists and people think that there will be one point, were the universe will stop expanding, and will start contracting. and it will end up in a big crunch were everything comes together.

Answer 11

According to astronomers' observations in the past decades, the "observable" universe is still expanding. You cannot dispute this at the moment even if you are sceptical about it.

In the future, the universe may stops expanding but this is for the future generations to "see".