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This is a spurious comment but how neat to be blasted by photons which have travelled for billions of years. I presume, if they're hitting the telescope they'r

by codyb 11y ago

This is a spurious comment but how neat to be blasted by photons which have travelled for billions of years. I presume, if they're hitting the telescope they're probably hitting me (which does make me feel a little self centered). I wonder how long they will keep traveling? The cosmos have been super interesting lately with those weird formations orbiting one star and the SETI project being refocused on another after detecting a strange sequence of lights. (I am barely a lay man here so bear with me if I'm making an ass of myself astronomers). And of course the Mars rover and those beautiful shots of Pluto. I look forward to a tremendous amount more. I've got a book on Einstein's Theory of Relativity, and a beautiful illustrated copy of Stephen Hawking's most famous work (I cannot seem to remember the title). After Catch-22 I believe I'll check them out. If anyone has any other suggestions for understanding the cosmos I'd be indebted.

hoorayimhelping 11y ago
A Brief History of Time is the book by Stephen Hawking. It's really approachable and easy to read. I also liked The Elegant Universe by Brian Greene. That was the first book I read where the author was able to explain both the standard model of physics and special and general relativity in ways that made sense to me.
- rootbear 11y ago
  Agreed about both books. The Elegant Universe explains clearly how Relativity and Quantum Mechanics conflict, and how String Theory solves that problem. I should reread the Hawking book, I haven't read it since college.
yeukhon 11y ago
How do they know the photons were from billions of years ago?
- cheez 11y ago
  If an object is measured to be a billion light years away, that means that light from that object takes a billion years to get here.
  - yeukhon 11y ago
    Right... but how do you know it takes a billion year to get here?
    - cheez 11y ago
      Measuring distances is an always active part of astronomy, as I understand it, but it starts with parallax. See this page for more info: https://en.wikipedia.org/wiki/Cosmic_distance_ladder https://en.wikipedia.org/wiki/Cosmic_distance_ladder
      - yeukhon 11y ago
        Thank you!
Justen 11y ago
I couldn't find anything concerning what you said about SETI. Do you have a link I could get?
- codyb 11y ago
  Yea sure, I found this on Fark.com [0]. Sorry coulda documented better! [0]- http://www.universetoday.com/122971/seti-institute-undertakes-search-for-alien-signal-from-kepler-star-kic-8462852/ http://www.universetoday.com/122971/seti-institute-undertake...

by codyb 11y ago

hoorayimhelping 11y ago

A Brief History of Time is the book by Stephen Hawking. It's really approachable and easy to read. I also liked The Elegant Universe by Brian Greene. That was the first book I read where the author was able to explain both the standard model of physics and special and general relativity in ways that made sense to me.

rootbear 11y ago
Agreed about both books. The Elegant Universe explains clearly how Relativity and Quantum Mechanics conflict, and how String Theory solves that problem. I should reread the Hawking book, I haven't read it since college.

yeukhon 11y ago

How do they know the photons were from billions of years ago?

cheez 11y ago
If an object is measured to be a billion light years away, that means that light from that object takes a billion years to get here.
- yeukhon 11y ago
  Right... but how do you know it takes a billion year to get here?
  - cheez 11y ago
    Measuring distances is an always active part of astronomy, as I understand it, but it starts with parallax. See this page for more info: https://en.wikipedia.org/wiki/Cosmic_distance_ladder https://en.wikipedia.org/wiki/Cosmic_distance_ladder
    - yeukhon 11y ago
      Thank you!

Justen 11y ago

I couldn't find anything concerning what you said about SETI. Do you have a link I could get?

codyb 11y ago
Yea sure, I found this on Fark.com [0]. Sorry coulda documented better! [0]- http://www.universetoday.com/122971/seti-institute-undertakes-search-for-alien-signal-from-kepler-star-kic-8462852/ http://www.universetoday.com/122971/seti-institute-undertake...