No one can hear you scream in space. <\/p>\n\n\n\n
They can\u2019t hear you laugh or cough or clap your hands, either.<\/p>\n\n\n\n
Sound is defined as vibrations that travel through a gas, liquid, or solid (e.g. the floor of the apartment upstairs) that is heard when those vibrations \u201cshake\u201d the eardrum of a person or animal.<\/p>\n\n\n
![\"cell](\"https:\/\/mariannedyson.com\/blog\/wp-content\/uploads\/2022\/08\/2022-iphone-1-300x177.jpg\")
So despite the loud booms of spacecraft exploding in movies, explosions in space are silent. However, secondary sound effects may be heard. Debris striking a hull or window of a spacecraft might cause a vibration inside that generates sound. Astronauts onboard the space shuttle reported hearing loud bangs as the metal structure of the vehicle shook during jet firings. A spacewalker banging on the hatch could be heard by those inside. Would touching helmets together work? Probably not much, considering the thickness of the glass, but combined with lip reading, it might help!<\/p>\n\n\n\n
But wait\u2014people on the ground talk to astronauts in space all the time. How can they do that? <\/p>\n\n\n\n
Radio waves are not sound waves. Radio is a band of electromagnetic waves of a frequency between 3 kilohertz to 300 gigahertz [NASA reference<\/a>]. Radio, just like visible light and x-rays and other frequencies of electromagnetic waves, travels at the speed of light in a vacuum.<\/p>\n\n\n\n Humans cannot hear radio waves directly. (Human eyes \u201csee\u201d electromagnetic waves in the visible light 1015<\/sup> Hz range.) But clever humans have learned how to convert the energy in a radio wave into vibrations that create sound waves that human and animal ears can sense.<\/p>\n\n\n\n Humans can generally hear sound waves between 12 Hz and 20 KHz. [Reference<\/a>] Other animals such as dogs, cats, and especially bats can hear higher frequencies, and some, including whales, much lower frequencies than humans. [Reference<\/a>]<\/p>\n\n\n\n The way an astronaut communicates with Mission Control is to speak into a microphone that converts the vibrations in the air made by her voice into radio waves. Those waves are (after being converted to the proper frequency and chopped into bits for transmission by a computer) sent through the vacuum of space, the atmosphere of Earth, and to a receiver on the ground that distributes the waves to the various devices that convert the radio waves back into sound such as flight controller headsets, someone\u2019s cell phone, or amplified speaker boxes in school auditoriums. A response likewise is converted to radio and back into sounds that the astronaut hears in her headset or through a speaker in a spacecraft or spacesuit.<\/p>\n\n\n But even at the speed of light, it takes time for the signals to travel back and forth in space\u2014so be prepared for a time lag between questions and answers. As I noted in a previous blog<\/a>, this time lag almost caused us to hang up on an astronaut who called our house from space!<\/p>\n\n\n\n Because aircraft and spacecraft cockpits are noisy, some sounds, like \u201cd\u201d and \u201ct\u201d are hard to distinguish from each other, especially considering various accents. To avoid confusion, the aviation and space community employ an aviation alphabet<\/a> to spell out each letter of a word. So instead of spelling out \u201cdot\u201d as \u201cdee oh tee\u201d which might sound like DoD or tot or even pot, in aviation\/space speak, it is \u201cDelta Oscar Tango.\u201d<\/p>\n\n\n\n I hope your brain enjoyed this science snack. In case you didn\u2019t hear, that\u2019s Sierra November Alpha Charlie Kilo!<\/p>\n\n\n\n Writing and Speaking About Space<\/strong><\/p>\n\n\n\n I\u2019m happy to announce I have a short story, \u201cThe Power of Apollo (16)\u201d and science article in the September\/October 2022 issue of Analog Science Fiction and Fact Magazine<\/a> (and my name is on the cover!). Single print copies can be found at bookstores and newsstands. Electronic subscriptions are available via Amazon<\/a>.<\/p>\n\n\n\n Want to live in space? Listen to the Big Picture Science podcast (also broadcast on NPR Science Fridays), \u201cBuilding a Space Colony<\/a>.\u201d I\u2019m quoted during the first segment which is followed by a segment with Author Emily St. John Mandel and another with John Adams of Biosphere 2.<\/p>\n\n\n\n Texas friends: I hope to see you at FenCon<\/a> in Dallas September 16-18, 2022. Stop by my autograph table to get signed copies of Shuttle Mission Control<\/em>, Fly Me to the Moon<\/em>, A Passion for Space<\/em>, and my newest children\u2019s title, Up in Space<\/em>. Autographed books can also be ordered through MarianneDyson.com\/orders<\/a>. Thank you for your support!<\/p>\n","protected":false},"excerpt":{"rendered":" August 2022 Science Snacks Newsletter by Marianne Dyson No one can hear you scream in space. They can\u2019t hear you laugh or cough or clap your hands, either. Sound is defined as vibrations that travel through a gas, liquid, or solid (e.g. the floor of the apartment upstairs) that is heard when those vibrations \u201cshake\u201d … Continue reading “Sound Space”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-320","post","type-post","status-publish","format-standard","hentry","category-science-snacks"],"_links":{"self":[{"href":"https:\/\/mariannedyson.com\/blog\/wp-json\/wp\/v2\/posts\/320","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mariannedyson.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mariannedyson.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mariannedyson.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mariannedyson.com\/blog\/wp-json\/wp\/v2\/comments?post=320"}],"version-history":[{"count":3,"href":"https:\/\/mariannedyson.com\/blog\/wp-json\/wp\/v2\/posts\/320\/revisions"}],"predecessor-version":[{"id":331,"href":"https:\/\/mariannedyson.com\/blog\/wp-json\/wp\/v2\/posts\/320\/revisions\/331"}],"wp:attachment":[{"href":"https:\/\/mariannedyson.com\/blog\/wp-json\/wp\/v2\/media?parent=320"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mariannedyson.com\/blog\/wp-json\/wp\/v2\/categories?post=320"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mariannedyson.com\/blog\/wp-json\/wp\/v2\/tags?post=320"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"author](\"http:\/\/mariannedyson.com\/blog\/wp-content\/uploads\/2022\/08\/2022-Headset-691x1024.jpeg\")