![]() It means that if you look at a galaxy 1 megaparsec away, it will appear to be receding away from us at 68 km/s. If you're a topical expert - researcher, business leader, author or innovator - and would like to contribute an op-ed piece, email us here. It's a distance: One megaparsec is 1 million parsec, which is 3.26 million light-years. You were probably following along just fine until that odd "per megaparsec" popped up. The more modern value is 68 kilometers per second per megaparsec, plus or minus a couple, but close enough. The number he got was way wrong, so I won't bother mentioning it, but good on him for trying. Edwin Hubble was the first to measure the expansion rate. ![]() It's as if a bunch of folks are at the edge of the cosmos, gently tugging at the fabric of space-time, stretching it. I swear this is true you can even try it for yourself at home! Even though the folks doing the pulling are moving at a constant speed, the apparent stretch changes with distance. You, standing in the middle, would correctly observe that your "universe" is expanding: any objects placed on that fabric would slowly move away from you.īecause stretchy stuff is stretchy, the objects on the fabric close to you would appear to move away with some speed, but the farther objects would appear to move faster. Let us assume they're choreographed well and are able to walk backward and pull at the same rate. ![]() Imagine a bunch of folks standing around the edges of a stretchy piece of fabric, tugging at it. A key feature of this expansion is how uniform it is.
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