What is the age of starlight?

Question

I was told that the light we see from stars is actually 5,000 years old due to the distance light has to travel to reach us. Is there any validity to this

Answer 1

No, except when the star is 5,000 lightyears from Earth.
A lightyear is a measure of distance. It's how far light travels in a year at about 186,000 miles per second. That is, about 5.87 trillion miles.

The star nearest our Solar System, Proxima Centauri, is about four lightyears away. The light traveling from Proxima Centauri to Earth takes about four years to get here. Thus, the light is four years old when we see it.

Another nearby star is Barnard's Star, which is six lightyears from Earth. It's light takes six years to get here, so that light is six years old when we see it.

The star Polaris, which we refer to as the North Star or North Pole Star, is 680 lightyears away. The light takes 680 years to travel to Earth, so it is 680 years old when we see it.

Most of the stars we see with the naked eye at night are within a few hundred lightyears, although a handful are as far away as 2,000 lightyears.

We don't see stars 5,000 lightyears away with the naked eye.

Viewing the light from stars more than about 2,000 lightyears away requires the use of a telescope.

The most distant objects seen from Earth are quasars, Telescopes are required to view them. They are 10-15 billion lightyears away. Their light takes 10-15 billion years to reach Earth, so their light is 10-15 billion years old.

An example of an object 5,000 lightyears away from Earth is the Lagoon Nebula, also known as M8. A nebula is a cloud of dust and gas in space, usually illuminated by one or more stars. Nebulae represent the raw material of which stars are made.

Answer 2

Well..... It is true that light from distant stars can take millions of years (or longer) to reach us. But the 'age' of a photon is a kinda delicate question. Since photons travel at the speed of light, time does not exist for them. That is, the time dilation effect predicted by Special Relativity (and actually measured on many, many space experiments) indicates that the rate of time passage for a photon is zero. So..... Since time doesn't really exist for a photon, its really not meaningful to talk about their 'age'.


Doug

Answer 3

Star light is limited to the hundreds of thousands of light years due to the limits of the resolution of our telescopes
Some of the stars we see do not exist any more.
Galaxy light is in the billions of light year range.
Most of the galaxies we see to-day don;t exist any more.

Answer 4

Hi.When you look up at the stars at night ,you are looking back in time many millions of years because it takes that long for the light to reach us. If you were ever fortunate to witness a super nova it would have happened millions of years ago,but to you it would appear to have just happened.

Cheers.