Age of the Universe?

Question

How can scientists estimate the age of the universe and give some exact figure, when time itself is not absolute according to Einsteins' theory of relativity.

Answer 1

At least 12.5 billion years old, give or take a few billion years - radioactive cosmochronometry.

Answer 2

13.7 billion years

Answer 3

Time is absolute in an inertial frame of reference. Time from one inertial frame can be converted to the time of another inertial frame.

It gets more difficult from there.  It turns out be very hard to figure out how old the Universe is.  But there are currently three lines of evidence and reasoning that lead to similar answers.  That gives us confidence that the answer is correct.

Models of stellar evolution tell us that the oldest stars found (and measured with spectroscopy) are about 13 billion years old.  The Big Bang model of how the Universe evolved suggests that this generation of still visible stars would have taken most of a billion years to form.  The Universe should not be older than the oldest stars.  So this is a lower limit.  Edwin Hubble's first estimate was that the Universe was 2 billion years old.  Not bad, but it was already known that the Earth was older.  Opps.  Better measurements have been made.

Careful measurements of the expansion rate of the Universe point to a Universe about 13.7 billion years old.

Analysis of the Cosmic Microwave Background is consistent with a Universe that is 13.7 billion years old.

Answer 4

The age of the universe is based on the speed of light, which IS an absolute in any reference frame.  The first estimate was made based on the Hubble constant for the expansion of the universe, first measured almost a century ago.  More recent, refined estimates are based on the cosmic microwave background radiation left over from the big bang - another type of light.

Answer 5

you are right that scientists cannot estimate age of universe exactly. Also it depends upon how do you view the universe.

There are 2 views; one is an infinite universe with no beginning or end another is finite universe with a precise beginning.

I believe in infinite universe. For me it is easy to understand the concept of infinite universe than finite universe. There is no proof so far that universe is either finite or infinite. Whatever observations we have so far do not confirm anything.

If you go with big bang theory then universe began about several billion years ago. You could get exact number from scientific books. They say time, universe everything began with big bang. They say nothing existed before big bang.

But they have not succeeded in proving it. So it is just a theory. They say noting existed before big bang. But they say it started from singularity. So " it started" from something. But they say that everything started from big bang. So if everything started from big bang then how did big bang started from singularity? it should have started from nothing.

They say big bang started from a dense high energy state. But they say nothing existed before big bang. If dense high energy state was the birth of big bang then big bang originated from this energy state and universe did not start from big bang.

I do not care whether the universe what we see today started from big bang or not. It might have been originated from big bang. It looks like some evience is there in this regard. What I really I care is;

When did universe began?  there is a difference between the current universe versus universe. It definitely looks like something always existed but in different different forms and shapes and energy levels.

So the current universe might have been started from big bang however big bang cannot be the beginning of universe itself. Universe might have existed in different shape, size, energy level etc before big bang.

Another problem with big bang theory is what is the end of universe? Now you have so much universe around us, do ou really believe that this is going to disappear one day in the future and nothing will exist after that? so that means the universe will continue forever in one or other shape, size and energy level.

If that is so then we are basically telling that " the universe began about 14 billion years ago and it will exist forver as something" means it will never end. Meand it will go on infinite and forever.

If that is so then why similarly we cannot go back in time and tell that it always existed as something. Why the future of universe is end less why not before?

My point is why all over a sudden universe born about 14 billion years ago and destined to exist forever in the future? how is that possible??

I feel universe always existed so we cannot estimate age. If you are asking about our current universe then it might have started in big bang and in that case it may be about 13 or 14 billion years old.

But I do not belive that time originated from the big bang for bthe universe itself.

And in my opinion Universe always existed as something. That must be very special about the universe. Since we have not created universe we cannot ask a question why or how can universe be infinite or always existed.

It must be unique only to universe to be infinite and always being existed without beginning or end.

Answer 6

Whenever scientists quote a figure, their results include a statistical error, eg. plus or minus 5 minutes, or plus or minus 10 billion years. The figure quoted in the media or in textbooks in the midpoint of the probability distribution. It is always an estimate based on whatever evidence or information the scientist has used.

Answer 7

Well, after reading all that techcno-babble - I honestly think that NO-ONE knows!  It's ok talking about fossils from "our" era, but how can you work out where and when the whole universe came from. An impossible task. Maybe David Tennant knows (?)

Answer 8

Well it is quite simple actually, whilst nobody knows the exact age of the Universe, it can be calculated by the observed fact that all galaxies outside of the Local Group show red shifts in their spectra, indicating that they are receding from us.

The velocity of the recession is proportional to their distance, established in the 1920's by Edwin Hubble (Hubble's Law). The Hubble constant (Ho) is currently accepted to be about 70 km s^-1 per mega parsec. Hubble's Law allows a galaxy's distance to be determined from its red shift once Ho is accurately known.

The recession of the Galaxies is usually interpreted as a general expansion of the universe (including space, radiation and, as it relates to your question, time as well).

The big bang is currently estimated to have taken place between 13-14 billion years ago.

I am not sure what you mean when you state time itself is not absolute according to Einsteins' theory of relativity, but I assume you are talking of time dilation as observed by two observers in different locations. That is a completely different thing as Einsteins' Laws relate to masses travelling at or close to light speed, not light itself which has no mass and is constant in a vacuum.

Answer 9

If we find an old fossil, are able to see what it is and when it was around, then we'll know at least one time that animals were living in. Keep moving back, and we'll come up with a date worth thousands and millions of years.

Answer 10

Well, first off, it's not really an exact figure. It fluctuates about a billion years either way depending on who you talk to. This is because other measurements involved in this one are very uncertain. We think, in general, that this is about 15 billion years, give or take.

The reason we think this is that we have a model which has stood up to some solid scrutiny over the past 30 years or so. Applying this model to the current universe, we can trace the theoretical path of light over time to the oldest known stars and galaxies. Extrapolating this path using the expansion model and the light's redshift, allows us to make a measurement of how long it took for the light to reach us.

This model we speak of when doing the extrapolation already incorporates the general relativistic notion of time, so we don't measure time differences (nor could we), we measure the path that light takes. Since relativity is pinned upon the speed of light, we've already accounted for the non-absoluteness, so to speak.

Good question.

Answer 11

The age of the universe is based on the speed of light, which is an absolute constant.  Because light takes time to travel, we're able to measure not only distances but the amount of time it took for the light from another star to travel to us.  By observing the most distant objects that can be viewed from the earth using long exposures and a telescope, we've discovered that light has only had about 13.73 billion years to travel, implying that the universe, in its current state anyway, has existed for that amount of time.  Anything further than 13.73 billion light years away is invisible, because the light from those sources hasn't reached us yet.