Is it true the light we see from the sun and stars is millions of years old?

Question

that is what my profesor said, but think something is wrong.
What about the heat from the sun? How long does that take to get here?

Answer 1

Not the light from the sun - it is only about 8 minutes old. The heat from the sun also travels at the speed of light, so it takes about 8 minutes to get here as well.

Some of the stars - most of them, actually - are in fact so far away that it takes the light millions of years to reach the earth.
So your professor is half right.

Answer 2

Yes, this is true. Even though light travels extremely fast (3.00 x 10^8 m/s) the universe is so vast, that this light takes a very long time to get to Earth. The closest star to Earth (besides the Sun) is Alpha Centauri, located about 4.37 light years away (41.5 trillion km). That means it takes 4.37 years for the light to get here. Since most stars are further, it can take that light decades, centuries, or even millenniums to get to Earth. It is conceivable that some of the stars emitting light 1 million years ago have burned out by now, so we see light from stars that are no longer there.

Answer 3

Not entirely true. Light, like everything else, has to move in order to get from one place to another. It's speed is incredibly high, but the distances in space (from the sun, and from the stars) are even longer. I'ts like a supersonic plane flying from orlando to Europe. It goes very fast, but the distance is too long for the plane to complete it in a few seconds.
When a star emits a flash of light, it will begin to travel, sometimes it takes a few years to arrive, because the star was very close to the earth, and sometimes millions of years, because it was very far away When it reaches the earth, the light is indeed very old (from a few years to several million). The sunlight, since the sun is the closest star to the earth, takes about 8 minutes to arrive to earth.
The heat travels just like light. Have you ever heard of "infrared light"? humans cannot see it, but when it touches something, it begins warming it up. The sun emmits both light, and infrared light (as well as others) and they all take 8 minutes to arrive.

Answer 4

If you built a Museum of Natural History, you MIGHT want to make it round. The main entrance is in the middle with Modern History exhibits. Out through the door is the Middle Ages exhibit, and in the next ring is the Ancient History department. As you get farther and farther from the entrance, you see older and older exhibits.

We stand on Earth looking out into space and seeing deep into the past of the Universe. Light from the stars in the belt of Orion started on their journey to Earth the same time Leif Ericson lost a coin toss, shrugged and said, "West it is!"

The light from that little fuzzy star in Andromeda left for Earth about when our ancestors were seriously reconsidering walking upright, as it was a "bad idea".

Now, with the right telescopes we can see an object that is nearly three times older than the Earth! Light from it started our way (long before even our Sun was a twinkle), only a few hundred thousand years after the Big Bang.

Pretty amazing stuff.

Answer 5

Not quite true.
The sun is right up there. 8 lightminutes away. And we can´t really make out stars at all that are millions of lightyears away. Most stars we can see are in our own galaxy which is about 100000 lightyears in diameter so the stars we see in the night sky are closer than that. So the light form the sun takes 8 minutes to get here and the light from the stars are in the range of 4.4 - 80 000 years old. Light from distant galaxies can take many millions of years to get here however but you usually need a telescope to see them. Only one, the Andromeda galaxy, can be seen with the naked eye and only under very good conditions. The Andromeda galaxy is over 2 million lightyears away meaning its light takes that long to get here.

Answer 6

Once it leaves the sun's surface, the light and heat take only about 8 minutes to reach Earth. However, that light and heat were formed in the core of the sun about a million years ago, and have been bouncing around inside it for all that time. That's how dense the sun is.

Answer 7

Yeah, sunlight is about 8 minutes old. Alpha Centauri, the nearest star, is about 4 light years away, so it's light has been travelling 4 years. Moonlight is about 2 seconds old. (really 8 min 2 sec since it's reflected Sunlight!)

The heat of sunlight is from the radiation which is part of the visible light so...yeah, the heat from the Sun: 8 minutes, +/-.

The furthest star in our galaxy is less then 50,000 light years away, so the light from any given star in our galaxy is LESS than 50,000 years old.

# of light years away = how many years old the light is.

Answer 8

Not, for the most part, with the naked eye. Sunlight takes eight minutes to reach us, and the visible stars are all within a couple of thousand light years. The only naked-eye object more than a million light years away is the Andromeda Galaxy; its light takes about about 2.5 million years to reach us.

What does take more than a million years is for energy from the inside of a star to reach its surface.

Answer 9

The sun's light is 8 minutes old, everything else could be years and years depending on distance. Your professor was right, but you heard him wrong about the sun.

Answer 10

The Sun lies at a distance of 8.2 light minutes (on average) from Earth.
The next nearest star (Proxima Centauri) lies at a distance of 4.3 light YEARS from Earth.
Considering that a light year is a roughly- estimated 6 trillion miles... The mind truly does boggle at the size of the neighborhood...