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dhd40
2007-Oct-17, 07:38 PM
Today´s APOD ( I Zwicky 18) says:

… The galaxy was also intriguing because it resembled galaxies forming in the very early universe, but mysterious since it is so nearby -- only 59 million light years away

This I don´t understand. Why can´t galaxies, 59 million light years away, have formed 13 billion years ago? I understand that galaxies 13 billion years away must have formed at least 13,.. billion years ago. But the other way round? Our own galaxy could have formed 13,.. billion years ago (I know it has not, for other reasons/evidences)

alainprice
2007-Oct-17, 07:50 PM
It could be 13 billion years old, and it could also be much younger. That's the problem. With evidence of primordial hydrogen and helium forming new stars, one expects a young galaxy.

01101001
2007-Oct-17, 08:34 PM
For convenience: APOD 2007 October 17 (http://antwrp.gsfc.nasa.gov/apod/ap071017.html)

For reference: NASA feature: Hubble Finds 'Dorian Gray' Galaxy (http://www.nasa.gov/mission_pages/hubble/news/zwicky.html)


The [Hubble] telescope found faint older stars contained within the galaxy, suggesting its star formation started at least one billion years ago and possibly as much as 10 billion years ago. The galaxy, therefore, may have formed at the same time as most other galaxies.

===


Our own galaxy could have formed 13,.. billion years ago (I know it has not, for other reasons/evidences)

Yeah, it could have.

University of Chicago press release: Scientist refines cosmic clock to determine age of Milky Way (http://www-news.uchicago.edu/releases/05/050629.milkyway.shtml)


According to Dauphas’ new method, the age of the Milky Way is approximately 14.5 billion years, plus or minus more than 2 billion years.

That age generally agrees with the estimate of 12.2 billion years—nearly as old as the universe itself— as determined by previously existing methods. Dauphas’ finding verifies what was already suspected, despite the drawbacks of existing methods: “After the big bang, it did not take much time for large structures to form, including our Milky Way galaxy,” he said.

Wikipedia: Milky Way :: Age (http://en.wikipedia.org/wiki/Milky_Way_galaxy#Age)


It is extremely difficult to define the age at which the Milky Way formed, but the age of the oldest stars in the Galaxy is now estimated to be about 13.6 billion years, nearly as old as the Universe itself.

Kaptain K
2007-Oct-17, 09:50 PM
dhd40,

The key phrase in your quote is resembled galaxies forming in the very early universe... Nowhere in the article does it say the galaxy formed in the early universe. In fact, it explains that a recent period of intense star formation was triggered by gravitational interaction with its neighbor.

dhd40
2007-Oct-18, 10:43 AM
dhd40,

The key phrase in your quote is resembled galaxies forming in the very early universe... Nowhere in the article does it say the galaxy formed in the early universe. In fact, it explains that a recent period of intense star formation was triggered by gravitational interaction with its neighbor.

My concern was actually the connection between “age” and “distance” in the APOD-text:


The galaxy was also intriguing because it resembled galaxies forming in the very early universe, but mysterious since it is so nearby -- only 59 million light years away

But maybe this is my misinterpretation

Kaptain K
2007-Oct-18, 03:05 PM
Well, my interpretation is different than yours. I'm not saying I'm right or that you're wrong.

dhd40
2007-Oct-19, 10:50 AM
Well, my interpretation is different than yours. I'm not saying I'm right or that you're wrong.

I would bet that mine is wrong, because my German-native-language-wired brain should be less efficient in interpreting English wording.
But that´s exactly what I like most, seriously! Learning, learning, ... and this forum is an excellent place to do this

Neverfly
2007-Oct-19, 11:04 AM
I interpreted it the same way dhd40 did.

I think it is because the words "unsual because" are used.

It implies that this galaxy is in the wrong place for its age.
As if, due to its age, it should be much further away.