Melbournefc Melbourne Demons Gus and Gawny Podcast Shirt
- meri elise
- 14 thg 6, 2023
- 2 phút đọc
One advantage of the numerous distance-measuring schemes in use, which overlap over a range of Melbournefc Melbourne Demons Gus and Gawny Podcast Shirt from nearby to very distant, is that astronomers can calibrate and corroborate their measurements with multiple approaches. Such calibrations and corroborations thus lend an additional measure of reliability to these schemes. Indeed, by comparing results using different methods, weaknesses have been identified in certain schemes. In most cases, additional studies have demonstrated ways to guard against and correct for known difficulties. As a single example of these multiple approaches, prior to 2011 the distance to the Pinwheel Galaxy was determined, based on measurements of Cepheid variable stars in the galaxy, to be 20.9 million light-years, with an uncertainty of 1.8 million light-years. As of September 2011, measurements of the light output of the 2011 Type Ia supernova in the Pinwheel Galaxy are completely consistent with this distance figure…. In short, distances to astronomical objects can be and have been measured with substantial accuracy and reliability. For the most part, the calculations involved employ only basic mathematics taught in high school. Thus the overall conclusion of a universe consisting of billions of galaxies, most of them many millions of light-years away, is beyond reasonable doubt at the present time..
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The Bluey Birthday Boy Custom Shirt thing here is not that we haven’t found aliens, but that we are learning so much about the universe so quickly. 20 years ago nobody knew that there are huge underground oceans on Europa and Enceladus, and methane lakes on Titan. 40 years ago there was no evidence of life at hydrothermal vents or life in deep ocean sediments—organisms that use forms of biology quite unlike that of the familiar organisms here on the surface. 25 years ago there was no evidence of even a single planet around another star! Now we know of thousands. The real number, in our galaxy alone, is probably hundreds of billions. The appropriate attitude here, I’d say, is a mix of giddiness and caution. Giddiness, because the rate of discovery right now is downright astonishing. Caution, because we still have so far to go in answering the big question: Are we alone?
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