The topic of Professor Elizabeth McGrath’s talk last Monday called, “Using Distant Galaxies as Cosmic Time Machines” was truly fascinating, and one of the highlights of the speaker series.\u00a0 In it she explained how we can judge the light that is given off by galaxies in our night sky, much of which is older than Earth itself, to determine how and why galaxies go through the changes they do and how they form.\u00a0 I think that this use of the past to understand the present is probably the most literal version of the idea, which I believe makes it all the more interesting.<\/p>\n
The main goal of Professor McGrath’s studies, at least as she presented it, was to determine how galaxies transform from disk shaped rotating galaxies to spherical clusters of stars with generally random motion.\u00a0 In order to understand how this metamorphosis occurs, Professor McGrath explained that we must look at the light we are currently seeing from the galaxies that is actually billions of years old in some cases.\u00a0 One of the most fascinating parts of the talk was when the professor put into perspective just how fast light moves.\u00a0 She stated that light travels at about 300,000 km\/s.\u00a0 This means that light takes about one second to travel from the moon to Earth, eight minutes from the sun, four years from the nearest star, Proxima Centauri, and 2.5 million years from the nearest galaxy.\u00a0 While this statistic alone is absolutely staggering, the most interesting thing about this idea is that our night sky is not up to date.\u00a0 We’re seeing the universe as it was hundreds, thousands, millions, and even billions of years ago.\u00a0 If today the galaxy closest to us was to randomly explode and cease to exist, we wouldn’t know for the next 2.5 millions years.<\/p>\n
Another absolutely mind-boggling idea put forth by Professor McGrath was the concept of dark-matter.\u00a0 Dark matter, as Professor McGrath explained differs from ordinary matter in that it does not give off any light.\u00a0 It is essentially invisible, yet it is still affected by gravity like ordinary matter.\u00a0 The halos of dark matter that were created by the big bang were essential in forming the galaxies of the universe because they trapped all of the ordinary matter in their center that would go on to be what those galaxies are comprised of.<\/p>\n
While this is interesting in it of itself, I think the most compelling idea pertaining to the existence of dark matter is that there is still so little we as a species know about it.\u00a0 Yes we know that it exists and has certain properties, but we have no idea what it looks like, how to find it, and how to harness it.\u00a0 I think that I am so drawn to this idea because we as a people have come so far over our relatively short existence in the universe.\u00a0 We have developed a vast, high tech civilization, explored parts of space, and yet there is so much out there that we have even begun to scratch the surface of.\u00a0 It is a bit scary and is one of those ideas that makes you feel minuscule in the grand scheme of our universe.\u00a0 However, I find it to be exciting there is still so much for us to learn.\u00a0 I just hope that we as a people will be around long enough to unlock these universal secrets.<\/p>\n","protected":false},"excerpt":{"rendered":"
The topic of Professor Elizabeth McGrath’s talk last Monday called, “Using Distant Galaxies as Cosmic Time Machines” was truly fascinating, and one of the highlights of the speaker series.\u00a0 In it she explained how we can judge the light that is given off by galaxies in our night sky, much of which is older than … <\/p>\n