Lightyear - distance versus time

[LogicalFallacy]

Alright, here's a nice juicy one... probably not a large topic, but interesting.

 

I am trying to figure out whether the term lightyear can be used as both a measure of distance (The distance light travels in a year - approx 10 trillion km) and time.

 

Strictly speaking, from a scientific point of view lightyear is a measure of distance not time. (And some people love pointing this out). However common sense tells me it is also a minimum measure of age of a star.

 

Lets take alpha centauri at 4.3 light years away. That's approx 43 trillion kilometers distance from us. Light has taken 4.3 YEARS to reach us. Thus we know that alpha centauri is at least 4.3 years old correct? So while we cannot determine absolute age, we can determine a minimum age. Am I correct?

 

Supernova 1989A 168,000 LY - 51 odd kilo parsecs  (Very long way!) So we know that supernova 1989A is at least 168,000 years old correct? The supernova occurred 168,000 years ago, and we saw it 30 years ago. (Approx)

 

Again we don't know for certain the age of the star from which SN1989A resulted, but we have a minimum. This is how we find out the approx age of the universe - we can see the oldest star clusters that they are around 13 billion LY away. So we know the universe is at least 13 billion years old. Current estimates put it at 13.77 billion, but some sources say it could be older because this is a minimum age. (Much like we know x stars are at least 1 million years old, but probably much older)

 

The reason I'm working through this is trying to deal with a creationist saying that light years are only a measure of distance (Ipso facto the universe is only 6,000 years old, but stars are millions of light years away) I want to explain the concept above. I have taken my research and tried to apply it in a simple to understand manner - you science gurus am I correct? Is there a better way to approach the topic of age of universe than saying "well it takes x millions of years for light to travel that distance therefore we know that star is at least x millions of years old?" 

 

Thanks

LF

[♦ Fuego ♦]

Sadly, I have only a scant amount of knowledge of such things. I do recall that in the presence of intense gravity, time is supposed to be different. I've always wondered if during the big bang or similar if the presence of so much mass distorted how time passed say between the very beginning of the bang until things separated further and time grew increasingly "normal" as things flew apart. I read one apologetic book saying that this distortion (from a 3rd party perspective) would give enough time for the vast age of the universe to happen quickly. But all I can remember from old Nova shows is that it is the reverse of that, that time moves more slowly around intense gravity and that the 3rd party position would seem to age quickly while the big bang was taking place.

 

I don't think time distorts very much around an average star, so I'd say that your idea is mostly valid. I'm happy to be corrected and learn something.

[Thurisaz]

Looking out into space means looking into the past. Exactly like you said Logical, if a given thing is 50,000 ly away, we're also seeing it like it was 50,000 years ago because the light needed that much time to get to our eyes.

 

Which is bad news for babblical cretinists with their majical 6,000 years-old fairy tale universe. This is the reason for all the hilariously absurd cretinist claims about the speed of light not being constant - it's a desperate attempt to weasel out of the obvious facts that the universe is motherfucking billions of years old.

[RogueScholar]

This was something I have pointed out to a deeply religious family member. His retort is "Satan is a deceiver and makes everything look like that." With an argument like that, I simply do not see the need to waste additional time and energy attempting to engage in dialogue with any hope of rational discourse or intellectual honesty.

[★ Citsonga ★]

Interestingly, when we look at the stars at night, we could very easily be looking at some stars that no longer exist. For example, if a visible star 20,000 light years away died 10,000 years ago, we can see it today even though it's no longer there, and it would continue being visible for another 10,000 years.

[bornagainathiest]

I have to agree with the RogueScholar, LF.

 

Minds that are closed to reason and rational thought can only be opened to those things by their owners.

 

Sometimes you just have to know when your time and efforts are wasted.

 

Thanks,

 

BAA.

 

 

[disillusioned]

That seems to be correct to me LF. Sadly, though, I too have my doubts about whether a young-earth creationist would find it convincing.

[LogicalFallacy]

4 hours ago, bornagainathiest said:

I have to agree with the RogueScholar, LF.

 

Minds that are closed to reason and rational thought can only be opened to those things by their owners.

 

Sometimes you just have to know when your time and efforts are wasted.

 

Thanks,

 

BAA.

 

 

 

Agree BAA,

 

However the topic is of personal interest as well so I thought I'd make sure my understanding of how we can apply light time-to-travel to determine a minimum age is correct.

 

Taking out all the science jargon, basically if we can see the light from a star 20,000 LY away, then it must be at least 20,000 years old.

 

I am now looking to see if opportunities arise with others who might actual talk about the why's and the wherefores rather than proclaiming divine knowledge that no one can refute.

 

7 hours ago, Fuego said:

I don't think time distorts very much around an average star, so I'd say that your idea is mostly valid. I'm happy to be corrected and learn something.

 

This is actually really interesting and something I didn't mention in the OP. Light moves at a constant in a vacuum, however light can bend, and gravity causes time to be different depending on where you are.

 

For example if you could travel at near the speed of light for say 100 years, only a few years would pass for you. But for an observer on earth 100 years would pass.

 

There is also the example of the astronauts on the space station - I think time passes more slowly for them (So instead of the body aging 100 days it might age 95 days... though I might have it backwards)

 

So if you were close to a supermassive red giant would time would be greatly affected by gravity? And is this time difference is relative to time on earth? So therefore is it possible for a star to age only a few years, while we here on earth think its aged 100 years?

 

I might need to do some more reading on this.

[♦ Fuego ♦]

There was a hokey movie called "Interstellar" that had this concept as a large part of the movie. Two astronauts leave a space station and travel to a planet near a neutron star (massive gravity) and then back to the space station. 10 years had passed for the remaining astronaut on the station. It wasn't the main theme of the movie, but figured prominently. The rest was just stupid for me. But Anne Hathaway with me...

[☆ pantheory ☆]

11 hours ago, LogicalFallacy said:

 

Agree BAA,

 

However the topic is of personal interest as well so I thought I'd make sure my understanding of how we can apply light time-to-travel to determine a minimum age is correct.

 

Taking out all the science jargon, basically if we can see the light from a star 20,000 LY away, then it must be at least 20,000 years old.

 

I am now looking to see if opportunities arise with others who might actual talk about the why's and the wherefores rather than proclaiming divine knowledge that no one can refute.

 

 

This is actually really interesting and something I didn't mention in the OP. Light moves at a constant in a vacuum, however light can bend, and gravity causes time to be different depending on where you are.

 

For example if you could travel at near the speed of light for say 100 years, only a few years would pass for you. But for an observer on earth 100 years would pass.

 

There is also the example of the astronauts on the space station - I think time passes more slowly for them (So instead of the body aging 100 days it might age 95 days... though I might have it backwards)

 

So if you were close to a supermassive red giant would time would be greatly affected by gravity? And is this time difference is relative to time on earth? So therefore is it possible for a star to age only a few years, while we here on earth think its aged 100 years?

 

I might need to do some more reading on this.

 

Yes, this subject is interesting. To advise you concerning the theoretical age of the universe according the Big Bang model is solely based upon the Hubble formula which relates to the observed redshifts of galaxies. This formula is based upon the premises of the Big Bang model as well as the theory of Special Relativity. If the Hubble formula is wrong, which I believe it is, then the universe could be much older. With the Hubble formula, regardless of the amount a galaxy is observed to be redshifted, the maximum age that will be calculated is 13.8 billion years of age.

 

I wrote a paper on this a few years back relating to type 1a supernovae and dark energy theory. I concluded that the dark energy hypothesis was wrong and so was the Hubble distance formula which relates to the distances of galaxies away from us. I concluded by reformulating another distance formula based upon a different cosmological model from the Big Bang, and its basis was not Special relativity. Using this alternative formulation I  we calculated that we presently can see about 60 billion years into the past since accordingly there would have been no big bang. The only limit to how far we could see into the past would accordingly be only the advancement of our technology concerning observation instrumentation.

 

The individual stars that we can observe are generally all within our own galaxy. We can see a few of the brightest stars in the Magellanic galaxy, the largest satellite galaxy of the Milky Way, and a few very bright individual stars in the Andromeda galaxy, the closest large galaxy to us, about 3.5 million light years away in distance and time.

 

Except for supernovas and the closest galaxies, we do not see individual stars in other galaxies, only collections thereof.

 

According to present theory as well as my own, when one gets close to a very massive dense gravitational body, such as a black hole or neutron star, time slows down for that person or entity. The same time dilation occurs when traveling at speeds somewhat near the speed of light. What is not known by present theory, but is a necessary part of my own related theories, is that as time dilates the entity slowly disintegrates. First the entity starts losing electrons from its molecular exterior first, the process progressing inwardly. Next molecular structures start breaking down. When enough break down occurs the entity, person, etc, disintegrates, breaks into small pieces which themselves finally disintegrate into atomic structures. The reason for the disintegration would be the friction of a background field. Such fields would move much faster than the molecular bodies within them resulting in intense friction, heating, then disintegration. 

 

Today such background fields are either known or theorized to exist: examples being: the zero-point field, gravitons, quantum foam, dark matter, dark energy, the Higgs field, etc.

 

There is no doubt concerning the intelligence of some religious people, but trying to talk to a young Earth creationist about science is like trying to talk to somebody in a foreign language when they haven't even learned the fundamentals, like buenos dias or como esta vd. in Spanish. Yes, some can parrot the fundamentals but truly don't understand or believe in them. It's a really hard sell. "You mean I'm not going to Heaven? Why should I believe that?" Such a discussion IMO would be totally wasting your time and theirs.

[LogicalFallacy]

Interesting ideas you have, and its interesting reading view different from the prevailing science.

 

It was believed in the 1920's that the universe was eternal until the expanding universe was discovered. However if your calculations are correct, the universe is much older than presently calculated. So is it possible then that the idea that the universe 'began' is incorrect? Is it possible that the universe has and always will exist? (And I don't mean possible as in its possible my pink unicorn might exist, I mean is there data that may lead us to conclude its a possibility?) You say you have written papers - you have published then in a science journal?

[☆ pantheory ☆]

3 hours ago, LogicalFallacy said:

Interesting ideas you have, and its interesting reading view different from the prevailing science.

 

It was believed in the 1920's that the universe was eternal until the expanding universe was discovered. However if your calculations are correct, the universe is much older than presently calculated. So is it possible then that the idea that the universe 'began' is incorrect? Is it possible that the universe has and always will exist? (And I don't mean possible as in its possible my pink unicorn might exist, I mean is there data that may lead us to conclude its a possibility?) You say you have written papers - you have published then in a science journal?

 

"So is it possible then that the idea that the universe 'began' is incorrect?" Is it possible that the universe has and always will exist?

 

Like the Big Bang model my own model has a beginning, but the universe would be countless times older. 

 

Yes it is possible that the universe is of infinite age, but not according to my own theories. IMO there are a lot of good arguments against this possibility.

 

Some of the most intelligent and well respected theorists of past centuries and continuing to the present day believe in an infinite universe in time, space, and matter. I believe in an older but not an infinite universe in neither time, space, nor matter. I believe infinity is only a mathematical concept but one that does not exist in reality concerning any point in time or aspect of reality. One could say that the future is infinite, but that is a continuum that cannot be summed at any point in time. If space goes on forever, that would be a continuum and infinite, but IMO it does not.

 

"You say you have written papers - you have published them in a science journal?"

 

Yes, my published papers can be seen at pantheory.org, along with my long book of theory, about 380 pages of personal theory contrary to a number of theories in modern physics which concerns about the last 100 years of theory in Physics.

 

I try to only discuss personal theory when it directly relates to the topic at hand, in this case a light year's distance as its meaning relates to time.  I guess the age of the universe could relate to that topic? 

 

I am writing you this reply from a hotel room in China, Cheers