Oldest and most distant object in the universe

Astronomers have found the oldest and most distant object in the universe a galaxy named UDFy -38135539 so distant that its light has taken 13.1 billion years to reach earth

The galaxy, which was spotted by Europe's Very Large Telescope in Chile, is the most remote cluster of stars, gas and dust ever measured.

The galaxy, which was spotted by Europe's Very Large Telescope in Chile, is the most remote cluster of stars, gas and dust ever measured.

Read more: www.dailymail.co.uk...

Although very interested in this subject I know very little, is this the find of the century, and how will it help us learn more about the begnings of our world?

I haven't read the article yet, but I am wondering how do they know it is 13.23 billion light years away?
I guess I will have to google it right after,
how far will 1 lumen or candela go? or be seen?

next take UDFy-38135539 galaxy, and point the same telescope in the exact opposite direction what is the farthest galaxy they can see from that point?

add the two together and then I wonder how far away each of the two galaxies are from each other?

the universe is estimated at 46.5 billion light years across per Every Joe

ok my head hurts, too much knowledge I need to rest my melon, back to the UFO section!

Originally posted by mysteryskeptic
add the two together and then I wonder how far away each of the two galaxies are from each other?

the universe is estimated at 46.5 billion light years across per Every Joe

13 billion years ago, two objects like this one in opposite directions would have been about 26 billion light years apart.

Today they would be about 93 billion light years apart, since "across means "diameter" to me, what you said every Joe said is not what he said, 46.5 is a radius not a diameter.

We're learning more and more. Judaism and today's science goes hand and hand. Not Christianity or Islam. Just Judaism. To make it clear.

Originally posted by dizzylizzy
Although very interested in this subject I know very little, is this the find of the century, and how will it help us learn more about the begnings of our world?

I doubt any one galaxy will provide a major breakthrough. From what I've seen we tend to look at these objects statistically, and in this respect there are lots of things we can do.

One thing that might be done would be to split the light with a prism and look at the spectral lines to determine the elemental composition. Why? To confirm if our theories about the age of the universe are true. We predict that metallicity of the universe increases over time as a result of fusion in stars (lighter elements combine to form heavier elements, that's called increasing metallicity). Therefore, the oldest object ever seen should have the lowest metallicity, and if it doesn't, then something is wrong with our theory.If it does, then it helps confirm our theory. I'm not sure if they're getting enough light from it to measure the metallicity though.

Metallicity

So what if that galaxy is gone now? i mean that is a awful long time to get to us...it may not even be there..in fact what if a lot of the stars we see are not there really? centuries ago went out. Wow that just boggles the mind.

I thought about that Optix, and wonder how far away in space our earth can be seen.

Thanks for links guys, will try take all info in.

How do the know our universe is 13 billion years old?

Originally posted by dizzylizzy
How do the know our universe is 13 billion years old?

Several different methods say it's 13.75 ± 0.17 billion years old, but I'm not so sure of the accuracy of that:

age of the universe

NASA's Wilkinson Microwave Anisotropy Probe (WMAP) project estimates the age of the universe to be 1.373±0.012×1010 years (13.73 billion years old, with an uncertainty of 120 million years).[8]

However, this age is based on the assumption that the project's underlying model is correct; other methods of estimating the age of the universe could give different ages. Assuming an extra background of relativistic particles, for example, can enlarge the error bars of the WMAP constraint by one order of magnitude.[9]

This measurement is made by using the location of the first acoustic peak in the microwave background power spectrum to determine the size of the decoupling surface (size of universe at the time of recombination). The light travel time to this surface (depending on the geometry used) yields a reliable age for the universe. Assuming the validity of the models used to determine this age, the residual accuracy yields a margin of error near one percent.[10]

Currently, this is the value most quoted by astronomers.

If we revised the age to 16 billion years based on a revised model, that wouldn't surprise me one bit. Once we understand dark matter and dark energy I'll have more confidence in the model, but until then, I don't think we can be too confident.

Originally posted by Optix
So what if that galaxy is gone now?

We'll never know because we can't see anything over 14 billion light years away, and it's probably over 40 billion light years away now. But given what we know about the lifetimes of stars we can probably surmise many of the stars are "dead" now. Our sun for example is thought to have a lifespan of 10 billion years and is about average, so stars like our sun would be gone 3 billion years ago. But there have probably been new stars to take their place, and it may have collided with other galaxies, etc in the last 13 billion years which would make it possibly quite different now. A lot can happen in 13 billion years.

reply to post by Arbitrageur


How do we know the lifespan of stars? math? I mean its not like we been studying them for Billions of years. not being caddy here just curious.

*** Duh i read you explanation up top, sorry.***

Originally posted by Optix
How do we know the lifespan of stars? math? I mean its not like we been studying them for Billions of years. not being caddy here just curious.

*** Duh i read you explanation up top, sorry.***

Actually I didn't explain that yet, but it's a good question.

The larger the star, the shorter its lifetime (if they have similar compositions to begin with). Ever heard the saying that "the candle that burns twice as bright lasts half as long"? This is because the larger mass star can create greater pressures at the core allowing fusion to take place at a greater rate, releasing energy at a higher rate but shortening the life of the star.

The rate of nuclear fusion can be estimated from measuring the energy emitted by the star (including light and other electromagnetic radiation at various frequencies). From that you can apply E=mc^2 to calculate how much mass is being converted to energy m=E/(c^2). For our sun that is about 400-600 tons of mass each second lost when hydrogen is converted into helium.

If you want to see the math, here it is in a homework problem:

www.ifa.hawaii.edu...

The Sun loses energy at rate of 3.78*1026 Joules/second, and if it has 1.26*1044 Joules of available energy, then we can divide the two to determine how long the Sun can shine: (3.78*1026 Joules/second)/(1.26*1044 Joules)=3.33*1017 seconds. We should convert this to more apropriate units of years, 3.33*1017 seconds/(60 sec/min*60 min/hr*24 hr/day*365 day/year)=1.05*1010 years or 10.5 billion years.

There's more information showing where those numbers used in the calculations come from in that link, if you're interested. But at least you can see the 10 billion years estimated lifetime of our sun can be calculated and isn't just a made-up number.

Thank you so much for the explanation. Math like that boggles my mind. Very interesting!
but i would say that something so hot and so huge burns at such a steady rate for sooo long. I mean if the sun goes up or down in temp just a little, it could kill us. The universe is such a enigma!

I also like your avatar of the Eagle Nebula and that would be one HUGE UFO if compared in size.

Oh i read this at Scientific America..

The majority of the gas in nebulae consists of molecules of hydrogen and helium--but most nebulae also contain atoms of other elements, as well as some surprisingly complex organic molecules. These heavier atoms are remnants of older stars, which have exploded in an event we call a supernova. The source of the organic molecules is still a mystery.

What type of organics ? wild!

Originally posted by Optix
Thank you so much for the explanation. Math like that boggles my mind. Very interesting!
but i would say that something so hot and so huge burns at such a steady rate for sooo long.

Brilliant observation/question. Actually it's NOT steady. The output of the Early sun was only something like 70% of what it is today. But since the sun is halfway through its life, using the current fusion rate may be a fair estimate for an average over the sun's lifetime. This raises the question called the Faint young Sun paradox

The faint young Sun paradox or problem describes the apparent contradiction between observations of liquid water early in the Earth's history and the astrophysical expectation that the Sun's output would be only 70% as intense during that epoch as it is during the modern epoch.

It may not be so much of a paradox though for the reasons mentioned in that link, plus they don't seem to mention that the Earth is moving away from the sun, so it used to be closer, and will be further away in the future.

The earth has been alternately a giant frozen snowball (maybe 630 million years ago as mentioned in that link) and a giant ball of molten rock in its history so the temperature extremes we like to complain about seem pretty small in comparison to those extremes.

What type of organics ? wild!

Wow that IS fascinating!

We still have a lot to learn about the universe!

A Wikipedia article devoted to this particular object discusses the various measures of distance. I thought I almost understood the different distance measures, but now, I am more confused than ever.

Redshift z = 8.55
Comoving (proper) distance: 30 Gly.
Light travel distance: 13 Gly.
Luminosity distance: 283 Gly.

The article doesn't mention angular distance, which is how far the object was (by one of those measures, I'm not sure which) when the light was emitted.

At the present rate of expansion, distances double in about 9 Gly. If the expansion rate was constant, in the time it took for the light to reach us, the distance would have increased by the factor 2^(13/9) = 2.72. Of course, we must consider that the rate of expansion seems to have increased in the last few billion years. Some time before that, it supposedly underwent a period of rapid inflation.

Another Wikipedia article on Distance measures (cosmology) might shed some light on the subject. I am still trying to see how the two articles agree with one another.

reply to post by Optix


This Hubble photos blog tells it in a quite straightforward way. Basically this galaxy is probably among the oldest things it is possible to see. It's from just after an era when the universe was too full of gas to let light through so we can't see anything older. Amazing stuff!