{"id":12617,"date":"2024-09-12T22:00:00","date_gmt":"2024-09-12T22:00:00","guid":{"rendered":"https:\/\/modernsciences.org\/staging\/4414\/?p=12617"},"modified":"2024-09-01T16:20:23","modified_gmt":"2024-09-01T16:20:23","slug":"what-is-space-made-of-an-astrophysics-expert-explains-all-the-components-from-radiation-to-dark-matter-found-in-the-vacuum-of-space","status":"publish","type":"post","link":"https:\/\/modernsciences.org\/staging\/4414\/what-is-space-made-of-an-astrophysics-expert-explains-all-the-components-from-radiation-to-dark-matter-found-in-the-vacuum-of-space\/","title":{"rendered":"What is space made of? An astrophysics expert explains all the components \u2013 from radiation to dark matter \u2013 found in the vacuum of\u00a0space"},"content":{"rendered":"\n
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\n Light from stars travels through space, which is mostly an empty vacuum.\n William Attard McCarthy – McCarthy’s PhotoWorks\/Moment via Getty Images<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\n Nilakshi Veerabathina<\/a>, University of Texas at Arlington<\/a><\/em><\/span>\n\n
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Curious Kids<\/a> is a series for children of all ages. If you have a question you\u2019d like an expert to answer, send it to curiouskidsus@theconversation.com<\/a>.<\/em><\/p>\n\n

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What is space made of \u2013 what does gravity actually bend? \u2013 Phil, age 12, Birmingham<\/strong><\/p>\n<\/blockquote>\n\n

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What comes to mind when you think of space? Imagine a friend boasting about a spacious building, stadium or museum they recently visited. Do you envision the building as vast and expansive? Is it simply very large, or does it seem empty? <\/p>\n\n

The word spacious does not necessarily mean empty. It simply indicates that there is enough room to move around the objects inside it. Similarly, outer space is not completely empty. It is vast and forever expanding, but there\u2019s a lot of stuff in it.<\/p>\n\n

As a kid, I used to wonder about questions like how far away the clouds are, what lies beyond Earth and how vast space is. This curiosity led me to pursue master\u2019s and Ph.D. degrees in astronomy. I have been teaching about these very concepts for two decades as a physics instructional professor<\/a> at the University of Texas, Arlington.<\/p>\n\n

Where does space begin?<\/h2>\n\n

Earth is surrounded by different layers of various gases. At sea level, Earth\u2019s atmosphere contains<\/a> about 100 billion molecules per cubic centimeter. As we ascend, the atmosphere becomes thinner and thinner. <\/p>\n\n

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\n At the K\u00e1rm\u00e1n line, Earth\u2019s atmosphere becomes space.<\/span>\n Mohatatou\/Wikimedia Commons<\/a>, CC BY-SA<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\n

At an altitude of about 50 to 62 miles (80 to 100 km), there isn\u2019t enough air for airplanes to fly<\/a>. This boundary, which separates the Earth\u2019s atmosphere from outer space, is called the K\u00e1rm\u00e1n line<\/a>, named after the Hungarian-American engineer and physicist Theodore von K\u00e1rm\u00e1n<\/a>. Everything above the K\u00e1rm\u00e1n line is called space. <\/p>\n\n

The density of space can vary, but, on average, it is around only 1 atom per cubic centimeter. Just imagine \u2013 a dice-sized cube of Earth\u2019s atmosphere contains billions of air particles. But in space, the same-sized cube contains only one or two particles. <\/p>\n\n

The interstellar medium and radiation<\/h2>\n\n

Space, or outer space, is a vast, near-perfect vacuum largely devoid of matter<\/a>. This vacuum contains very few particles compared with Earth\u2019s atmosphere. However, it\u2019s not entirely empty.<\/p>\n\n

Space is dotted with scattered matter called the interstellar medium<\/a>, which includes hydrogen and helium atoms. These are the most common elements in space, and they exist in both charged and neutral forms. The interstellar medium also contains cosmic dust<\/a> \u2013 tiny particles of various elements, including carbon and silicon, scattered throughout space.<\/p>\n\n

High-energy particles<\/a> called cosmic rays \u2013 which are primarily protons<\/a> and the nuclei of atoms<\/a> \u2013 travel through space at nearly the speed of light. Cosmic rays come from various stars including our Sun, as well as from supernovae<\/a>, the material falling into black holes<\/a>, colliding galaxies<\/a> and more. <\/p>\n\n

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\n A map of cosmic microwave background radiation from when the universe was only 380,000 years old. The colors are artificial and show tiny temperature variations, which represents heat left over from the origin of the universe.<\/span>\n NASA\/WMAP Science Team<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\n

Space is filled with various forms of radiation, including cosmic microwave background radiation<\/a>. This is remnant heat from the origin of the universe. High-energy cosmic events like supernovae and black holes also emit X-rays<\/a> and gamma rays<\/a>.<\/p>\n\n

Magnetic fields<\/a> generated by stars, planets and many other celestial bodies also permeate space. These fields influence the motion of charged particles by attracting or repelling them like magnets.<\/p>\n\n

Dark matter and dark energy<\/h2>\n\n

Scientists predict that an as-yet unseen form of matter<\/a> that does not emit light or energy, called dark matter<\/a>, makes up a significant portion of the universe\u2019s mass. Researchers guess that it exists because they can see its gravitational pull on other visible matter. <\/p>\n\n

Similarly, scientists predict a mysterious form of energy<\/a> called dark energy<\/a> is driving the accelerated expansion of the universe. Unlike dark matter, dark energy is not related to matter or gravitational forces, but it\u2019s a property of space itself. <\/p>\n\n

Imagine the universe as a balloon. Dark matter is like the balloon\u2019s material, affecting its shape, while dark energy is like the air being pumped into it. It doesn\u2019t change the balloon\u2019s material, but it influences how quickly the balloon expands. <\/p>\n\n

Does space warp? Can gravity bend space?<\/h2>\n\n

Space can also warp. Imagine that space is like a big, stretchy trampoline. If you put a heavy ball, like a bowling ball, in the middle of the trampoline, it makes a big dip downward. This dip is similar to how space warps around something big, like a planet or a star. The bigger the ball, the stronger the gravity and the deeper the dip.<\/p>\n\n

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