... were recently collected by the newly refurbished Hubble Space Telescope. John Wood, one of my favorite scientists at NASA, from my days on the Hubble Repair team, sometimes send over some new results that he finds significant. Since I wandered into optics to develop instruments for astronomers, after getting my initial degrees in Physics and accidently in Astrophysics, I’ve always tried to keep up, a little. As you may recall, after a lot of politics, the Hubble was granted a new mission and some new instruments were installed. They immediately went forward to repeat taking the now famous Hubble Deep Field shots, those with the longest possible exposure and in doing so, with the new equipment, resulted in collecting AND DETECTING some of the oldest photons ever, some 13 billion years old, shown below.
This comes to us from
http://spaceflightnow.com/news/n1001/11hubble/
which, of course, you should click on, if you have just 1 more minute.
This got me trying to figure out how to relate to a 13 billion year old photon. I didn’t get too far, but, try this. I have had the misfortune to fly, so far, some 1.5 million miles on United, starting in 1992. Since it is easy to relate to a mile, now I can somewhat relate to 1.5 million of them. In a typical year, I fly some 100,000 miles. Now, in round numbers, it is 25,000 miles around the earth, so, I fly about 4 times around it in equivalent miles in a year, at an average of 500 miles per hour, (not including airport time), thereby spending about 200 hours a year in an airplane. Now light, on the other hand, inserted into a fiber, goes around the world 7 times, IN ONE SECOND, nice trick (where I’ve conveniently ignored the refractive index of the fiber). So, light can go in somewhat less than a second, what it takes me 200 hours to accomplish. So, now I can almost relate to what light can do in one second. A few other round numbers to play with, there are very nearly, pi*10^7 seconds in a year. (pi=3.14). So, light can go around the earth about 7pi*10^7 (~210,000,000) times in a year. Now we’re getting close to one billion. So, in 5 years, light can go around the earth 1 billion times. So, here is an irrelevant statistic. If light would travel around the world (it doesn’t since the it prefers a straight line, but, these days we could put it into a fiber), then, a pulse launched when I was born, would have now circled the earth over 10 billion times. But, now 13 billion light years is another matter. Since the 10 billion circlings of the earth only represent 1/7th of a second per circle, versus the distance travel by light in a year. How to relate to that? Well, the distance to the sun is slightly less than 100,000,000 miles (93 million actually). Light that arrives here at earth is about, 10 minutes old. (568 seconds). In a day then, light can go to the sun and back, about 125 times. So, finally, in a year, light can go to the sun and back about 125*365 times, or about 45,000 times. At this point, I don’t think that helps me relate, but, almost.
As an aside, Doug Goodman, being Doug, has a bag of poppy seeds, carefully measured out, to contain 1,000,000 seeds – should you every try to visualize 1,000,000 of something. Then, you only need to visualize 13,000 of those (it is about the size of a sandwich baggie) to get to 13 billion. Good luck.
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