Thread: A question about Carl Sagan's Pale Blue Dot

I am a believer in all of Sagan's views and I believe the Earth is billions of years old...however...when I read the following point from Carl Sagan it raised a question in my mind.

Sagan talks about the age of the Earth and the universe. He talks about how bible thumpers believe the Earth and universe is around 6000 years old.

He claims that the Earth must be older than 6000 years old because we see light coming from distant galaxies that is millions and billions of light years away...meaning that the light must be at least that old.

Isn't it possible though, at least theoretically, that the universe could be billions of years old but the Earth not as old?

In my mind, just because we see light coming from distant galaxies that is old, doesnt mean that we ourselves are old.

Can someone add insight here?

Originally Posted by l3randonf

He claims that the Earth must be older than 6000 years old because we see light coming from distant galaxies that is millions and billions of light years away...meaning that the light must be at least that old.

Isn't it possible though, at least theoretically, that the universe could be billions of years old but the Earth not as old?

Yes, that is definitely possible. The earth is most certainly younger than the universe itself. The universe (according to WMAP data and other sources) is between 12 and 14 billion years old.

However, we also know that the age of the earth is much larger than 6,000 years for MANY more reasons than just because of the light we see from distant galaxies. Earth is about 4.6 billion years old. More on how this is known here.


TBH, I'm not certain that you are accurately representing what Carl said. I am unfamiliar with that particular argument... That we know earth is older than 6000 years due to light from distant galaxies. We know the age of the earth from other sources of evidence.

One way or the other, I've learned not to put too much attention into the claims of creationists, as they've been wrong at every turn thus far when subjected to scrutiny.


Btw... Welcome. Do be sure to see my sig, and the links within.

The age of the earth is determined via various geophysical evidence, such as the magnetization or freezing of ironin rocks, the time it takes rocks to form under pressure from silts and silicates and radiometric dating methods of rocks here on earth and asteroids.

While these do not compute an actual age for the Earth, they do establish a lower limit (the Earth must be at least as old as any formation on it).

What is known to almost 99.999999% certainty is that the earth is much much younger than the Universe. I think the most recent estimate is around 4 and a half billion years.

I suspect Sagan was trying to refute the biblical account of creation, which has the universe, not just the earth, as being slightly over six thousand years old.

thanks for the replies.

also, on a random note, what does Sagan mean by this quote:

"If you wish to make an apple pie from scratch, you must first create the universe."

lol...I feel like Carl is almost making a joke of somekind here. Anyways, I find it amusing and have never been able to make out exactly what he means.

I think he's talking about elements. Without things like Stars, the only element the universe has is Hydrogen. To get hydrogen you have to have a universe for hydrogen to be in. It's a bit of a joke yes, the whole 'regressing' question of 'but where did X come from'. If you go far enough back, the content of an apple pie was caused by the big bang. - or at least was impossible without it.