1 00:00:02,040 --> 00:00:07,080 Speaker 1: Welcome to brain Stuff from How Stuff Works, Hey, brain Stuff, 2 00:00:07,120 --> 00:00:10,479 Speaker 1: Lauren Vogel bomb here. Imagine a comet hurtling through the 3 00:00:10,520 --> 00:00:14,160 Speaker 1: nothingness of space. It smashes into a planet, causing destruction, 4 00:00:14,440 --> 00:00:17,639 Speaker 1: but also bringing life. That's because hitching a ride on 5 00:00:17,640 --> 00:00:20,200 Speaker 1: the surface of the comet were tiny traces of organic 6 00:00:20,280 --> 00:00:24,080 Speaker 1: material or even alien eggs, explaining how life could spread 7 00:00:24,079 --> 00:00:27,880 Speaker 1: across the cosmos and arrive on our planet. Pant Spermia, 8 00:00:28,040 --> 00:00:30,960 Speaker 1: meaning seeds Everywhere, is the name of the theory that 9 00:00:31,080 --> 00:00:34,199 Speaker 1: life on Earth may have cosmic origins, and it's been 10 00:00:34,320 --> 00:00:37,760 Speaker 1: both debated by scientists and featured in works of science fiction. 11 00:00:38,600 --> 00:00:41,520 Speaker 1: Now a group of nearly three dozen scientists from around 12 00:00:41,520 --> 00:00:44,360 Speaker 1: the world are putting a tweak in the theory, suggesting 13 00:00:44,479 --> 00:00:47,680 Speaker 1: not that Earth's earliest life had outer space origins, but 14 00:00:47,800 --> 00:00:52,360 Speaker 1: that panspermia may be responsible for the Cambrian explosion. That's 15 00:00:52,400 --> 00:00:55,160 Speaker 1: a point in Earth's history approximately four hundred and fifty 16 00:00:55,160 --> 00:00:58,560 Speaker 1: one million years ago when most major animal groups appear 17 00:00:58,640 --> 00:01:02,120 Speaker 1: in the fossil record. In their article cause of Cambrian 18 00:01:02,160 --> 00:01:06,200 Speaker 1: Explosion Terrestrial or Cosmic, published in eighteen issue of the 19 00:01:06,280 --> 00:01:10,679 Speaker 1: journal Progress in Biophysics and Molecular biology. Thirty three scientists 20 00:01:10,720 --> 00:01:14,679 Speaker 1: tie the rise of unique animals tartegrades, octopuses, and the 21 00:01:14,800 --> 00:01:17,480 Speaker 1: bevy of other odd and unique animals that flourished at 22 00:01:17,520 --> 00:01:21,240 Speaker 1: that time to pan spermia, suggesting that many of these 23 00:01:21,280 --> 00:01:25,400 Speaker 1: relatively bizarre and never before seeing creatures descend from organic 24 00:01:25,560 --> 00:01:30,160 Speaker 1: alien material. The author's right. It takes little imagination to 25 00:01:30,200 --> 00:01:33,720 Speaker 1: consider that the Precambrian mass extinction event was correlated with 26 00:01:33,760 --> 00:01:37,160 Speaker 1: the impact of a giant lifebearing comet and the subsequent 27 00:01:37,240 --> 00:01:40,759 Speaker 1: seating of Earth with new cosmic derived cellular organisms and 28 00:01:40,880 --> 00:01:44,600 Speaker 1: viral genes. But we haven't cracked the mystery of life's 29 00:01:44,600 --> 00:01:47,720 Speaker 1: origins just yet. This new paper isn't built on any 30 00:01:47,760 --> 00:01:50,840 Speaker 1: new discoveries or research. It's a literature review that, for 31 00:01:50,960 --> 00:01:54,160 Speaker 1: the most part, references the author's own existing work. But 32 00:01:54,360 --> 00:01:57,480 Speaker 1: that's by design. The authors acknowledge. They write, we are 33 00:01:57,520 --> 00:02:00,440 Speaker 1: acutely aware that mainstream thinking on the or gin and 34 00:02:00,560 --> 00:02:03,480 Speaker 1: further evolution of life on Earth is anchored firmly in 35 00:02:03,520 --> 00:02:07,200 Speaker 1: the terrestrial paradigm. Our aim here is to facilitate further 36 00:02:07,240 --> 00:02:13,040 Speaker 1: discussion in the biophysical, biomedical, and evolutionary science communities. Panspermia 37 00:02:13,200 --> 00:02:15,800 Speaker 1: is at this point only a concept, but it dates 38 00:02:15,840 --> 00:02:18,040 Speaker 1: back well before the last hundred years or so of 39 00:02:18,080 --> 00:02:20,600 Speaker 1: modern science fiction. Way back at the turn of the 40 00:02:20,639 --> 00:02:24,400 Speaker 1: eighteenth century, French diplomat and natural historian Benois de May 41 00:02:24,520 --> 00:02:27,520 Speaker 1: proposed that life across the cosmos could have been seeded 42 00:02:27,639 --> 00:02:31,440 Speaker 1: from space, and a few scholars even interpret ancient Greek 43 00:02:31,440 --> 00:02:35,200 Speaker 1: philosopher and Axagorus of Clazomenas musings along the same lines. 44 00:02:35,480 --> 00:02:38,639 Speaker 1: He spoke vaguely of cosmic seeds two thousand, five hundred 45 00:02:38,680 --> 00:02:43,200 Speaker 1: years ago. The paper has already drawn skepticism after biologist 46 00:02:43,280 --> 00:02:46,440 Speaker 1: Francis Westall, for instance, points out that while some forms 47 00:02:46,480 --> 00:02:49,600 Speaker 1: of extremophile life have been observed surviving in the vacuum 48 00:02:49,600 --> 00:02:52,360 Speaker 1: of space for short periods of time, this new paper 49 00:02:52,480 --> 00:02:56,880 Speaker 1: suppositions would require eggs, embryos, or other cells survived thousands 50 00:02:56,919 --> 00:03:00,400 Speaker 1: of years, if not more, in space. West All told 51 00:03:00,480 --> 00:03:03,799 Speaker 1: Newsweek when discussing the paper, Unfortunately, it is all too 52 00:03:03,840 --> 00:03:06,440 Speaker 1: easy to pull information out of the literature to support 53 00:03:06,440 --> 00:03:09,960 Speaker 1: one's hypothesis. Nature is incredible, and I do not think 54 00:03:10,040 --> 00:03:13,040 Speaker 1: it is necessary to call on extraterrestrials to explain it. 55 00:03:14,080 --> 00:03:16,880 Speaker 1: An alternate theory for the Cambrian explosion goes by the 56 00:03:16,960 --> 00:03:20,640 Speaker 1: name Snowball Earth, and it suggests that seven fifteen million 57 00:03:20,720 --> 00:03:23,160 Speaker 1: years ago our planet became encased in ice for a 58 00:03:23,240 --> 00:03:26,480 Speaker 1: hundred and fifty million years, killing most existing life forms, 59 00:03:26,720 --> 00:03:30,360 Speaker 1: and that a massive thought allowed for an explosion of biodiversity. 60 00:03:35,520 --> 00:03:38,320 Speaker 1: Today's episode was written by Christopher Hasseiotis and produced by 61 00:03:38,320 --> 00:03:40,760 Speaker 1: Tyler Klang. For more on this and lots of other 62 00:03:40,840 --> 00:03:43,880 Speaker 1: life affirming topics, visit our home planet, how stuff works 63 00:03:43,960 --> 00:03:55,640 Speaker 1: dot com.