Jump to content

The Speed of Light


Recommended Posts

I cannot wrap my head around certain aspects of Time, Light Speed and various discoveries said to be "Hundreds of Billions of Light Years away".

My first question is...How can scientists detect stars that are more than 13.7 Billion light years away? If the Universe is 13.7 Billion years old, light could not be travelling for more than 13.7 Billion Years as nothing existed before this. In my way of thinking, everything began expanding out from a central point so anything opposite to the earth from the centre is farther than 13.7 Billion light years to a maximum of double the age of the universe or 27.4 Billion Light years. I watched a doc that stated various boundaries that have been discovered. They were said to be Hundreds of Billions of Light Years away. How could anything travel this distance within 13.7 Billion Years?

Link to comment
Share on other sites

2 hours ago, Chris Sawatsky said:

I cannot wrap my head around certain aspects of Time, Light Speed and various discoveries said to be "Hundreds of Billions of Light Years away".

My first question is...How can scientists detect stars that are more than 13.7 Billion light years away? If the Universe is 13.7 Billion years old, light could not be travelling for more than 13.7 Billion Years as nothing existed before this. In my way of thinking, everything began expanding out from a central point so anything opposite to the earth from the centre is farther than 13.7 Billion light years to a maximum of double the age of the universe or 27.4 Billion Light years. I watched a doc that stated various boundaries that have been discovered. They were said to be Hundreds of Billions of Light Years away. How could anything travel this distance within 13.7 Billion Years?

That would be the case if the universe were static, but the universe is expanding

Link to comment
Share on other sites

On 11/2/2023 at 5:37 PM, Chris Sawatsky said:

How can scientists detect stars that are more than 13.7 Billion light years away?

Light from that star was emitted about 8 billion years ago when the star was about 5.5 billion light years away, both time and proper distance per the cosmic (expanding) coordinate system.  That star, if it currently exists (unlikely), is a burnt out husk right now and doesn't shine at all. More likely it blew up and doesn't exist at all, or is a black hole or some such.

On 11/2/2023 at 5:37 PM, Chris Sawatsky said:

If the Universe is 13.7 Billion years old, light could not be travelling for more than 13.7 Billion Years

Yes, it could not have been traveling for longer than that, and it doesn't need to. Such distances use an expanding coordinate system where light speed isn't constant.  But also, absolutely nothing we see in the sky now was emitted further away than about 6 billion light years away (proper distance). Sure, the galaxy/quasar/whatever may be 40 billion light years away now, but we're seeing it where it was long long ago, which was much closer. The CMB light is the oldest, and that light was emitted from less than one billion light years away. That light isn't from any 'star', but it is from the formation of the first hydrogen atoms.

On 11/2/2023 at 5:37 PM, Chris Sawatsky said:

In my way of thinking, everything began expanding out from a central point

You're going to have to unlearn this common misconception if you want to actually understand cosmology. The big bang happened literally everywhere and was never a 'point', and there is no rushing of material from a point into 'empty space' so to speak.

On 11/2/2023 at 5:37 PM, Chris Sawatsky said:

I watched a doc that stated various boundaries that have been discovered. They were said to be Hundreds of Billions of Light Years away.

Getting your information from peer-reviewed sources is a far better choice. I can find a 'doc' that states just about any nonsense I wish. Your source apparently claims to have measured something outside the observable universe, something which is by definition a contradiction.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.