Hubble's Bubble Constant (The expansion of the Universe)
Entry posted by csoup
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In my last blog I briefly described how red-shifting has proven the existence of the expansion of the universe but there is much more to it than that as Dr. Freeze describes in her book The Cosmic Cocktail and I try to explain here.
Edwin Hubble was the scientist brave enough to disagree with Einstein, but also the one smart enough to prove Einstein wrong. The debate at the time was on the subject of what the universe was actually doing, scientists had already established the fact that the universe was homogenous (looks the same at every point) and isotropic (looks the same in every direction), but Einstein also believed that the universe was static or always looked the same.
That's where Hubble came in, he observed light from many different galaxies and noticed that the rays of light were red-shifted, a term I have already described in my last blog post (PSA: Our Galaxies going to collide with another...), which basically states that a longer wave length of light shows that the source is increasing in distance from us.
Imagine it like this, if you went to your local candy store, purchased some Hubble Bubble Gum, and began to blow the gum into a giant bubble it could be a model of our universe! Say there were large specks of pink sugar in your gum, as the bubble expanded the specks of sugar would increase in distance from each other even though they are in no way changing in size or placement really. This is just like our universe, although the distance of us from other galaxies is increasing, we are unaffected by the expansion. This again proves the two cosmological observations stated earlier, the universe looks the same at every point, or every sugar speck, since everything is expanding from each speck, and it also looks the same in every direction, because the bubble is increasing in size everywhere. Another common analogy for this idea is the "raisin bread model", where the universe is the bread expanding, and the unaffected galaxies the raisins, it serves the same purpose but in no way highlights the point that Hubble's name sounds like a bubble gum brand.
Anyways back the real point, Hubble was able to apply this law into an equation known as Hubble's Law which stated v (speed) = d (distance) times H (Hubble's constant of universal expansion). This equation finally convinced people that the universe was expanding and a static universe was just a silly notion, sorry Einstein.
Furthermore, the equation has been applied to find the age of the universe (14 billion years) since the constant measure the stretching of the universe and we can then use it in reverse to find when the distance was 0 and the universe had just began!
All this and more came from a guy who's name now resides on the most powerful telescope in the universe
...and the tastiest gum of all the galaxies.
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