True Crime Dark Matter Detective Investigation - what is dark matter?
Stupendous Science Stuff
[{'start': '1.680', 'end': '7.120', 'text': "This is no ordinary mystery. There's a"}, {'start': '4.720', 'end': '10.719', 'text': 'crime playing out on the grandest stage'}, {'start': '7.120', 'end': '13.120', 'text': 'imaginable, space itself. Galaxies are'}, {'start': '10.719', 'end': '16.320', 'text': 'behaving badly. Stars are spinning out'}, {'start': '13.120', 'end': '19.199', 'text': 'of line. And something something is'}, {'start': '16.320', 'end': '22.039', 'text': 'warping the fabric of reality. Welcome'}, {'start': '19.199', 'end': '25.519', 'text': 'to the crime scene of the'}, {'start': '22.039', 'end': '28.320', 'text': 'universe. It all began in the 1930s.'}, {'start': '25.519', 'end': '30.880', 'text': 'Astronomer Fritz Sawiki was analyzing'}, {'start': '28.320', 'end': '33.760', 'text': 'the Koma cluster, a massive group of'}, {'start': '30.880', 'end': '36.399', 'text': 'galaxies. But something was off. The'}, {'start': '33.760', 'end': '39.000', 'text': 'galaxies were moving way too fast to be'}, {'start': '36.399', 'end': '41.760', 'text': 'held together by the visible matter'}, {'start': '39.000', 'end': '46.879', 'text': 'alone. By all accounts, they should have'}, {'start': '41.760', 'end': '46.879', 'text': 'scattered like marbles across a cosmic'}, {'start': '47.000', 'end': '54.000', 'text': "desk. But they didn't. Something was"}, {'start': '50.719', 'end': '58.640', 'text': 'holding them back. He called it Duno'}, {'start': '54.000', 'end': '61.000', 'text': 'Mataria. dark matter. Why? Well, the'}, {'start': '58.640', 'end': '64.320', 'text': 'Koma cluster is a very dense part of the'}, {'start': '61.000', 'end': '67.439', 'text': 'universe with over 1,000 galaxies.'}, {'start': '64.320', 'end': '69.600', 'text': "That's 1,000 Milky Ways of our galaxy."}, {'start': '67.439', 'end': '71.360', 'text': "And they've been around for 8 billion"}, {'start': '69.600', 'end': '74.400', 'text': 'years.'}, {'start': '71.360', 'end': '76.479', 'text': 'So after all this time, you would expect'}, {'start': '74.400', 'end': '79.080', 'text': 'them to either be a victim of gravity'}, {'start': '76.479', 'end': '82.720', 'text': 'and merge'}, {'start': '79.080', 'end': '87.520', 'text': 'together or fly apart because gravity'}, {'start': '82.720', 'end': '87.520', 'text': 'was very weak and could not keep them'}, {'start': '88.200', 'end': '93.680', 'text': 'together. Decades passed. Scientists,'}, {'start': '91.200', 'end': '96.240', 'text': 'detectives with better tools, dug deeper'}, {'start': '93.680', 'end': '99.439', 'text': 'into the mystery. They looked at spiral'}, {'start': '96.240', 'end': '101.920', 'text': 'galaxies and found another clue. Stars'}, {'start': '99.439', 'end': '104.000', 'text': 'on the outer edges were moving as fast'}, {'start': '101.920', 'end': '108.159', 'text': 'as those near the center, some even'}, {'start': '104.000', 'end': '110.479', 'text': "faster. That's not normal. On any wheel,"}, {'start': '108.159', 'end': '113.520', 'text': 'a dot further from the center moves'}, {'start': '110.479', 'end': '115.520', 'text': 'faster than one with a shorter radius.'}, {'start': '113.520', 'end': '117.600', 'text': "Planets move differently because they're"}, {'start': '115.520', 'end': '120.280', 'text': 'not connected, and time for them to'}, {'start': '117.600', 'end': '123.759', 'text': 'circle the sun is different. Mars takes'}, {'start': '120.280', 'end': '126.399', 'text': "687 Earth days. For Saturn, it's 19"}, {'start': '123.759', 'end': '128.560', 'text': 'Earth years. The speed of the planets'}, {'start': '126.399', 'end': '130.120', 'text': 'are different and they move slower. the'}, {'start': '128.560', 'end': '133.520', 'text': 'further they are from the'}, {'start': '130.120', 'end': '135.680', 'text': "sun. Here's Earth, Mars, and Saturn"}, {'start': '133.520', 'end': '139.040', 'text': 'showing speed decreasing as we move'}, {'start': '135.680', 'end': '140.800', 'text': 'further from the sun from left to right.'}, {'start': '139.040', 'end': '143.200', 'text': 'For spiral galaxies, it should be'}, {'start': '140.800', 'end': '146.160', 'text': 'similar. Stars on the outer edges should'}, {'start': '143.200', 'end': '148.080', 'text': 'move slower than those near the center.'}, {'start': '146.160', 'end': '150.560', 'text': 'Based on the mass of all the visible'}, {'start': '148.080', 'end': '153.040', 'text': 'matter, those stars should slow down.'}, {'start': '150.560', 'end': '155.519', 'text': "But they don't. They're moving faster"}, {'start': '153.040', 'end': '157.440', 'text': "than those near the center. There's just"}, {'start': '155.519', 'end': '160.040', 'text': 'not enough stars in the outer regions of'}, {'start': '157.440', 'end': '163.519', 'text': 'spiral galaxies to cause the rotational'}, {'start': '160.040', 'end': '165.360', 'text': 'velocities. How much is missing? A lot.'}, {'start': '163.519', 'end': '167.920', 'text': 'Based on the velocity, there should be'}, {'start': '165.360', 'end': '170.319', 'text': 'six times more mass than we see. Where'}, {'start': '167.920', 'end': '173.120', 'text': "is it? It's as if they're riding on"}, {'start': '170.319', 'end': '176.879', 'text': 'invisible rails of gravity. Something is'}, {'start': '173.120', 'end': '179.120', 'text': "there. We just can't see it. It's dark."}, {'start': '176.879', 'end': '180.879', 'text': "That's why we call this mystery dark"}, {'start': '179.120', 'end': '183.200', 'text': "matter. Hey, if you're enjoying this"}, {'start': '180.879', 'end': '186.239', 'text': 'cosmic mystery, give the video a like.'}, {'start': '183.200', 'end': '188.800', 'text': 'Subscribe down there and select the all'}, {'start': '186.239', 'end': '191.280', 'text': 'notifications by clicking on the bell so'}, {'start': '188.800', 'end': '193.800', 'text': "you don't miss any other mindblowing"}, {'start': '191.280', 'end': '197.319', 'text': 'science stuff. Okay, back to the'}, {'start': '193.800', 'end': '200.519', 'text': "mystery. Let's round up the possible"}, {'start': '197.319', 'end': '203.239', 'text': 'suspects. Could it be black'}, {'start': '200.519', 'end': '207.280', 'text': 'holes? Nope, not enough of them.'}, {'start': '203.239', 'end': '210.239', 'text': 'Nutrinos? Too fast. Rogue planets? Too'}, {'start': '207.280', 'end': '213.120', 'text': 'few. Modified gravity? Did Einstein get'}, {'start': '210.239', 'end': '216.239', 'text': "it wrong? Maybe. But it couldn't explain"}, {'start': '213.120', 'end': '219.200', 'text': 'all the observations. Each theory hits a'}, {'start': '216.239', 'end': '222.080', 'text': "dead end. But there's one suspect we"}, {'start': '219.200', 'end': '222.080', 'text': 'keep coming back'}, {'start': '223.159', 'end': '228.879', 'text': "to. A type of matter that doesn't emit"}, {'start': '226.159', 'end': '231.159', 'text': "or absorb light. It doesn't interact"}, {'start': '228.879', 'end': '234.000', 'text': 'with regular atoms, but it does have'}, {'start': '231.159', 'end': '238.000', 'text': 'mass enough to bend the very structure'}, {'start': '234.000', 'end': '238.000', 'text': 'of spaceime. Dark'}, {'start': '238.360', 'end': '244.599', 'text': "matter. Here's the thing. We can't see"}, {'start': '241.040', 'end': '247.120', 'text': 'dark matter, but we can see its'}, {'start': '244.599', 'end': '249.280', 'text': 'effects. It bends light from distant'}, {'start': '247.120', 'end': '251.319', 'text': 'galaxies like a funhouse mirror at a'}, {'start': '249.280', 'end': '255.439', 'text': 'cosmic'}, {'start': '251.319', 'end': '258.639', 'text': 'carnival. Abel 1689 is a galaxy cluster'}, {'start': '255.439', 'end': '261.120', 'text': 'in the constellation Virgo over 2.3'}, {'start': '258.639', 'end': '263.199', 'text': "billion lightyear away. That's like"}, {'start': '261.120', 'end': '266.240', 'text': "really far. It's a massive galaxy"}, {'start': '263.199', 'end': '268.160', 'text': 'cluster and acts as a gravitational lens'}, {'start': '266.240', 'end': '271.120', 'text': 'so we can figure out where the dark'}, {'start': '268.160', 'end': '275.560', 'text': 'matter is hiding. But it was in the'}, {'start': '271.120', 'end': '279.199', 'text': 'bullet cluster that gave us the smoking'}, {'start': '275.560', 'end': '282.320', 'text': 'gun. Two galaxy clusters collided and'}, {'start': '279.199', 'end': '284.320', 'text': "gave us clues about what's inside. Let's"}, {'start': '282.320', 'end': '286.639', 'text': 'reconstruct the scene of the crime. Each'}, {'start': '284.320', 'end': '288.880', 'text': 'cluster, each with billions of stars,'}, {'start': '286.639', 'end': '291.840', 'text': "but that's not the focus here. The stars"}, {'start': '288.880', 'end': '294.560', 'text': 'were mostly unaffected by the collision,'}, {'start': '291.840', 'end': '297.280', 'text': 'missing each other. The red hot gas in'}, {'start': '294.560', 'end': '300.160', 'text': 'the galaxy seen in X-rays, the ordinary'}, {'start': '297.280', 'end': '302.160', 'text': 'matter. Now that was interesting. And'}, {'start': '300.160', 'end': '304.840', 'text': 'the blue dark matter calculated by'}, {'start': '302.160', 'end': '307.919', 'text': 'gravitational lensing that surrounds the'}, {'start': '304.840', 'end': '310.479', 'text': 'galaxies. Very interesting. When the'}, {'start': '307.919', 'end': '313.120', 'text': 'clusters crash, the ordinary matter, the'}, {'start': '310.479', 'end': '316.560', 'text': 'red gas and dust affected by gravity'}, {'start': '313.120', 'end': '319.360', 'text': 'slowed down and stretched. But the blue'}, {'start': '316.560', 'end': '321.919', 'text': 'dark matter just kept going, separated'}, {'start': '319.360', 'end': '325.199', 'text': 'without distortion. The invisible thief'}, {'start': '321.919', 'end': '329.280', 'text': 'had left its fingerprints. And now you'}, {'start': '325.199', 'end': '329.280', 'text': "can see why it's called the bully"}, {'start': '330.680', 'end': '335.039', 'text': 'cluster. Despite the mountain of'}, {'start': '332.960', 'end': '338.320', 'text': "evidence, we still don't know what dark"}, {'start': '335.039', 'end': '340.160', 'text': 'matter really is. Is it a particle, a'}, {'start': '338.320', 'end': '342.639', 'text': "force, something we haven't even"}, {'start': '340.160', 'end': '345.039', 'text': 'imagined yet? Scientists are building'}, {'start': '342.639', 'end': '347.759', 'text': 'elaborate traps underground, hoping to'}, {'start': '345.039', 'end': '349.840', 'text': 'catch a glimpse of dark matter. While'}, {'start': '347.759', 'end': '351.600', 'text': 'ordinary matter is made up of atoms,'}, {'start': '349.840', 'end': '354.479', 'text': 'dark matter is thought to consist of'}, {'start': '351.600', 'end': '356.560', 'text': 'exotic particles not yet identified.'}, {'start': '354.479', 'end': '360.400', 'text': 'Candidates include weakly interacting'}, {'start': '356.560', 'end': '362.720', 'text': 'massive particles, WIMPs, and axion.'}, {'start': '360.400', 'end': '364.720', 'text': 'WIMPs are hypothetical particles that'}, {'start': '362.720', 'end': '367.120', 'text': 'would be completely different from the'}, {'start': '364.720', 'end': '369.280', 'text': 'type of matter we know. They would only'}, {'start': '367.120', 'end': '371.360', 'text': 'interact with regular matter through'}, {'start': '369.280', 'end': '373.520', 'text': 'gravity and the weak nuclear force,'}, {'start': '371.360', 'end': '376.800', 'text': 'which would explain why they are largely'}, {'start': '373.520', 'end': '378.720', 'text': 'invisible in space. If wimps exist,'}, {'start': '376.800', 'end': '380.720', 'text': 'mathematical modeling shows there must'}, {'start': '378.720', 'end': '383.520', 'text': 'be about five times more of these than'}, {'start': '380.720', 'end': '385.600', 'text': 'normal matter, which coincides with the'}, {'start': '383.520', 'end': '387.680', 'text': 'abundance of dark matter that we observe'}, {'start': '385.600', 'end': '389.520', 'text': 'in the universe. This means we should be'}, {'start': '387.680', 'end': '391.520', 'text': 'able to detect them through their'}, {'start': '389.520', 'end': '394.000', 'text': 'collisions, as this would cause the'}, {'start': '391.520', 'end': '396.240', 'text': 'charged particles on Earth to recoil,'}, {'start': '394.000', 'end': '398.880', 'text': 'producing light that we can observe in'}, {'start': '396.240', 'end': '401.039', 'text': 'experiments. Axons are low mass,'}, {'start': '398.880', 'end': '403.199', 'text': "slowmoving particles that don't have a"}, {'start': '401.039', 'end': '406.240', 'text': 'charge and interact weakly with other'}, {'start': '403.199', 'end': '408.800', 'text': "matter, so they're hard to detect. Only"}, {'start': '406.240', 'end': '410.960', 'text': 'these special axons would explain dark'}, {'start': '408.800', 'end': '413.759', 'text': "matter, lighter or heavier, and we'd see"}, {'start': '410.960', 'end': '416.639', 'text': 'them. If axons do exist, they could'}, {'start': '413.759', 'end': '418.880', 'text': 'decay into a pair of light particles,'}, {'start': '416.639', 'end': '422.080', 'text': 'which means we could detect them by'}, {'start': '418.880', 'end': '424.720', 'text': 'looking for these pairs. The Axion dark'}, {'start': '422.080', 'end': '427.400', 'text': 'matter experiment is searching for axons'}, {'start': '424.720', 'end': '429.680', 'text': 'by trying to detect these pairs of light'}, {'start': '427.400', 'end': '432.880', 'text': 'particles. But the suspect remains'}, {'start': '429.680', 'end': '435.039', 'text': 'elusive, silent, invisible, patient.'}, {'start': '432.880', 'end': '437.360', 'text': 'Despite numerous experiments, these'}, {'start': '435.039', 'end': '439.680', 'text': 'particles have yet to be detected,'}, {'start': '437.360', 'end': '442.070', 'text': 'leaving the true nature of dark matter'}, {'start': '439.680', 'end': '442.390', 'text': 'an open question.'}, {'start': '442.070', 'end': '445.120', 'text': '[Applause]'}, {'start': '442.390', 'end': '447.919', 'text': '[Music]'}, {'start': '445.120', 'end': '450.880', 'text': 'Stars are organized into galaxies which'}, {'start': '447.919', 'end': '453.599', 'text': 'in turn form galaxy groups, galaxy'}, {'start': '450.880', 'end': '456.080', 'text': 'clusters, superclusters and filaments'}, {'start': '453.599', 'end': '459.039', 'text': 'which are separated by immense voids'}, {'start': '456.080', 'end': '461.680', 'text': 'created by vast foamike space, the'}, {'start': '459.039', 'end': '464.400', 'text': 'cosmic web. These filaments act as'}, {'start': '461.680', 'end': '466.160', 'text': 'highways for galaxy information guiding'}, {'start': '464.400', 'end': '469.520', 'text': 'the distribution of matter in the'}, {'start': '466.160', 'end': '471.759', 'text': 'universe. So far, these filaments seem'}, {'start': '469.520', 'end': '474.160', 'text': 'to be the best explanation of where the'}, {'start': '471.759', 'end': '477.599', 'text': "dark matter is hiding and how it's"}, {'start': '474.160', 'end': '480.000', 'text': 'connected to the regular visible matter.'}, {'start': '477.599', 'end': '482.440', 'text': 'The case of dark matter is still open.'}, {'start': '480.000', 'end': '485.039', 'text': 'Clues are everywhere, and the hunt'}, {'start': '482.440', 'end': '487.400', 'text': 'continues. One day, we may finally shine'}, {'start': '485.039', 'end': '489.919', 'text': "a light on the universe's darkest"}, {'start': '487.400', 'end': '492.879', 'text': 'secret. In the meantime, want to learn'}, {'start': '489.919', 'end': '496.759', 'text': "about black holes? Click here, and we'll"}, {'start': '492.879', 'end': '496.759', 'text': 'see you next time.'}, {'start': '497.640', 'end': '501.500', 'text': '[Music]'}]