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Thread: A Chart About the Relative Age of Adjacent Galaxies

  1. #1 A Chart About the Relative Age of Adjacent Galaxies 
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    I have found this chart here:
    http://sci.esa.int/science-e/www/obj...odylongid=1729

    and it states a factor for adjacent universes called R.A. I have guessed, but I am not sure, whether it means relative age. If so, can someone tell me how to read the units?


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  3. #2 Right Ascension 
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    http://en.wikipedia.org/wiki/Right_ascension

    I believe this is what the chart means.


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  4. #3  
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    Toooz; This is what I understand and as said before its based on BBT, the accepted cosmology theory for 'age of universe', not necessarily true.

    The age of any galaxy, can't be older than the universe, said to be 14.2 billion yo, and 13,2 byo, on your site.

    We think our sun is 4.5 byo, based on how old the earth is. According to whats been found, the oldest material on earth is about 4byo and some time allowing for formation and cooling, we assume about 4.5 byo in total.

    Then we have determined the mass/luminosity of our sun, its current age and can compare this to other stars.

    The oldest star in a galaxy would give an approximate age, however it is assumed complex galaxies began forming about the same time no more than 13 million years ago.

    Comparing our star to estimates of a visible star in our or any near by galaxy is th following;

    T (age of a star) = 1 divided by M to the 2.5 power...(M is mass of our sun)

    You can google 'formula age of a star' and get more on this formula...several links.

    If we had no idea how old the Universe was, these figures would not necessarily work, since the Hubble Constant and other data is fixed on a set age limit....

    I am a little curious, why your interested in Galaxy age??? Its good to see this interest however...
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  5. #4 Say what? 
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    http://answers.yahoo.com/question/in...4021958AAdNDmR

    If you meant this post, it’s complete rubbish. The Sun’s mass is 2*10^30 kg which makes T=10^-31 kg. The result isn’t even in a measure of time.


    Half of the uranium in an ore decays into lead every billion years. This knowledge was used to determine an age for the Earth of about 4.5 BY. When light from the Sun passes through a prism it makes a spectrum or rainbow. The spectrum has gaps where specific atoms absorbed that frequency of light. This technique was used to determine that the Sun was mostly hydrogen with a few percent of helium. The fusion of hydrogen into helium was understood well enough to conclude that it took about 4.7 BY for the percentage of helium to reach the observed value. This technique has been applied to many other stars, some of which were about twelve BY old. Other techniques have been used (red shift, etc.) and an average age of 13.7 BY is estimated for the age of the universe.
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  6. #5  
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    Arch; Actually the formula did come from that site. However the rest came from various 'computer models of stellar evolution' and as stated, 'as I understand them'. However most everything is based on a pre-established universal age and the age of the earth, drawing back to certain conclusions. Frankly the entire issue, is speculatively based, IMO.
    Our SS being a second or third generation, is still argued among many issues which could be argued. Confusing the issues with 'Toooz' would hardly seem a worth while venture and the reason I asked the authors reasons....

    Thanks for your clarification and as an occasional poster, welcome to this forum. Your technique is familiar, but not often seen or required on this forum. Will look forward to your expertise on other issues....
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  7. #6  
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    Thanks!
    You can imagine my surprise when the number 1 hit was the above formula. So much for Yahoo answers.
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  8. #7  
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    R. A. = Right Ascension

    Dec = Declination

    They're just two coordinates used to locate objects on the celestial sphere (a targeting system/concept used in astronomy).

    The units can be a little confusing, but are based on the measurements of a clock, and the degrees of a compass.

    Declination gives you the position of an object off of the celestial equator. An object at 0-degrees is right on the equator. An object to the North or South of the celestial equator is represented as being + or - a number of degrees, respectively. So something over the North pole of the celestial sphere would be at +90 degrees, while something at the Southern position would be at -90 degrees.

    The right-ascension gives the measurement of left or right position in the sky, but does this by using a concept like that of a hand going around a clock. When the time is 11:00am, you know that the hand of the clock is 11 hours from 0 (24-hr time of course). The hand of a clock always goes the same way, and the same is true in right-ascension. An hour in R.A. is a 1/24th slice of the sky. So if something is at 3 hours, it's 3/24ths of the sky (or 45-degrees) to the east. Measurements R.A. are zeroed to the vernal equinox.

    The reason astronomers use right-ascension calculations over simple longitude is because unlike making measurements on the surface of the earth, trying to find something in the sky is made complex by the fact that the sky moves as the Earth rotates.

    That's all pretty quickly written, but hopefully you get the jist of it all. :P
    Wolf
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    "Be fair with others, but then keep after them until they're fair with you." Alan Alda
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