| | | | | | photo: CERN Cliông xã pholớn lớn view expanded History of the Universe. Bạn đang xem: Bang |  Did you know that the matter in your body toàn thân is billions of years old? According lớn most astrophysicists, all the matter found in the universe today -- including the matter in people, plants, animals, the earth, stars, và galaxies -- was created at the very first moment of time, thought lớn be about 13 billion years ago. The universe began, scientists believe, with every speông xã of its energy jammed inkhổng lồ a very tiny point. This extremely dense point exploded with unimaginable force, creating matter & propelling it outward lớn make the billions of galaxies of our vast universe. Astrophysicists dubbed this titanic explosion the Big Bang. The Big Bang was lượt thích no explosion you might witness on earth today. For instance, a hydrogen bomb explosion, whose center registers approximately 100 million degrees Celsius, moves through the air at about 300 meters per second. In contrast, cosmologists believe the Big Bang flung energy in all directions at the tốc độ of light (300,000,000 meters per second, a million times faster than the H-bomb) & estimate that the temperature of the entire universe was 1000 trillion degrees Celsius at just a tiny fraction of a second after the explosion. Even the cores of the hotchạy thử stars in today"s universe are much cooler than that. There"s another important unique of the Big Bang that makes it quality. While an explosion of a man-made bomb expands through air, the Big Bang did not expand through anything. That"s because there was no space lớn expvà through at the beginning of time. Rather, physicists believe sầu the Big Bang created & stretched space itself, expanding the universe. A Cooling, Expanding Universe | photo: Space Telescope Science Institute As the early universe cooled, the matter produced in the Big Bang gathered into stars và galaxies. | For a brief moment after the Big Bang, the immense heat created conditions unlượt thích any conditions astrophysicists see in the universe today. While planets và stars today are composed of atoms of elements lượt thích hydroren & silibé, scientists believe sầu the universe bachồng then was too hot for anything other than the most fundamental particles -- such as quarks & photons. But as the universe quickly expanded, the energy of the Big Bang became more and more "diluted" in space, causing the universe lớn cool. Popping open a beer bottle results in a roughly similar cooling, expanding effect: gas, once confined in the bottle, spreads into lớn the air, và the temperature of the beer drops. Rapid cooling allowed for matter as we know it khổng lồ form in the universe, although physicists are still trying lớn figure out exactly how this happened. About one ten-thousandth of a second after the Big Bang, protons và neutrons formed, và within a few minutes these particles stuchồng together khổng lồ form atomic nuclei, mostly hydrogen & helium. Hundreds of thousands of years later, electrons stuông xã khổng lồ the nuclei khổng lồ make complete atoms. Xem thêm: So Sánh Canon 6D Và 5D Mark Iii Khi Phơi Sáng Lâu Với Iso Cao About a billion years after the Big Bang, gravity caused these atoms lớn gather in huge clouds of gas, forming collections of stars known as galaxies. Gravity is the force that pulls any objects with mass towards one another -- the same force, for example, that causes a ball thrown in the air to fall khổng lồ the earth. Where vì planets lượt thích earth come from? Over billions of years, stars "cook" hydrogen & helium atoms in their hot cores khổng lồ make heavier elements like carbon và oxyren. Large stars explode over time, blasting these elements inkhổng lồ space. This matter then condenses into the stars, planets, and satellites that Cosplay solar systems lượt thích our own. How vày we know the Big Bang happened? Astrophysicists have sầu uncovered a great khuyến mãi of compelling evidence over the past hundred years to tư vấn the Big Bang theory. Aao ước this evidence is the observation that the universe is expanding. By looking at light emitted by distant galaxies, scientists have sầu found that these galaxies are rapidly moving away from our galaxy, the Milky Way. An explosion lượt thích the Big Bang, which sent matter flying outward from a point, explains this observation. | Did you know that the static on your television is caused by radiation left over from the Big Bang? | Another critical discovery was the observation of low levels of microwaves throughout space. Astronomers believe sầu these microwaves, whose temperature is about -270 degrees Celsius, are the remnants of the extremely high-temperature radiation produced by the Big Bang. Interestingly, astronomers can get an idea of how hot the universe used lớn be by looking at very distant clouds of gas through high-power telescopes. Because light from these clouds can take billions of years to reach our telescopes, we see such bodies as they appeared eons ago. Lo & behold, these ancient clouds of gas seem khổng lồ be hotter than younger clouds. Scientists have sầu also been able to lớn uphold the Big Bang theory by measuring the relative sầu amounts of different elements in the universe. They"ve sầu found that the universe contains about 74 percent hydrogen & 26 percent helium by mass, the two lighthử nghiệm elements. All the other heavier elements -- including elements common on earth, such as carbon & oxygen -- ảo diệu just a tiny trace of all matter. So how does this prove sầu anything about the Big Bang? Scientists have shown, using theoretical calculations, that these abundances could only have been made in a universe that began in a very hot, dense state, and then quickly cooled & expanded. This is exactly the kind of universe that the Big Bang theory predicts. next page...
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