From physics how can we figure out how old the earth and the universe is?

[dcderek24]

i am a former creationist that is just learning about science. I am not trying to disprove anything i just want to learn. i was hid away from science all my life growing up in a fundamentalist household and church.
anway i have learned about radiometric dating and various ways scientists can figure out how old the Earth is.
what about through physics?
how through physics can we figure out the age of a star and the age of things of the universe including earth.

i greatly appreciate any answers in advance. I am also being bomboarded with creationist questions by my friends or old friends and family. and i just like to know for my own curiosity.

 

[Phyisab****]

It will be difficult to answer this question without writing an entire book.

http://en.wikipedia.org/wiki/Star

http://en.wikipedia.org/wiki/Cosmic_microwave_background_radiation

http://en.wikipedia.org/wiki/Hubble's_law

http://en.wikipedia.org/wiki/Sun

 

[Chalnoth]

The ages of stars are a bit more complicated. For our own solar system, it's pretty easy, because we can just check the ages of asteroids using radiometric dating. This gives us a good estimate for the age of our own Sun as well.

But there are no direct methods for detecting the ages of other stars, unfortunately. Instead, we rely largely upon model estimates. The basic way this is done is to compare three variables: brightness, temperature, and mass. Main sequence stars stay about the same mass for most of their life after formation. But the brightness and temperature change as the star ages: the star becomes gradually brighter and hotter as it ages. So if the star is in a multiple-star system that allows us to measure its mass, then we can use the relationship between how bright/hot it is and its mass to give us an estimate of the age.

To get an idea of how the age depends upon this relationship, we have to use theoretical models of stellar evolution. It's unfortunate that we only really have one strong data point to confirm our theories (our own Sun). Partly because of this, our estimates of the ages of individual stars are extremely uncertain. Interestingly enough, we have a better handle on the age of the universe itself than we have on the ages of individual stars!

Anyway, you can read more on how stars age here:
http://en.wikipedia.org/wiki/Stellar_evolution

 

[Chronos]

Radioactive dating is a very powerful tool for determining Earth's age. All such studies strongly indicate Earth is about 4.5 billion years old.

 

[Ich]

You need to know the http://www.talkorigins.org/origins/faqs.html" archive. This is not exactly the very first time those questions have been asked and answered.
If some specific questions remain, ask here at PF.

 

[Chalnoth]

You need to know the http://www.talkorigins.org/origins/faqs.html" archive. This is not exactly the very first time those questions have been asked and answered.
If some specific questions remain, ask here at PF.

Ah, yes, talkorigins is fantastic for debunking a wide variety of creationist claims. I particularly like the FAQ and the "post of the month" series.

 

[nickthrop101]

the universe they can measure the speed of exceleration, taking in mind that the universe is speeding up, and can measuse when it began :)

 

[Jack21222]

the universe they can measure the speed of exceleration, taking in mind that the universe is speeding up, and can measuse when it began :)

Please tell me English isn't your first language...