RSS iconTwitter iconFacebook icon

The Trek BBS title image

The Trek BBS statistics

Threads: 148,440
Posts: 5,878,614
Members: 26,314
Currently online: 422
Newest member: CaptainRodrigue

TrekToday headlines

Retro Review: Tattoo
By: Michelle Erica Green on Oct 3

Evaluation Ordered For Lien
By: T'Bonz on Oct 2

Shatner To Receive Award
By: T'Bonz on Oct 2

New Star Trek Beyond Pictures
By: T'Bonz on Oct 1

Star Trek Beyond Dubai Press Conference
By: T'Bonz on Sep 30

October-November 2015 Trek Conventions And Appearances
By: T'Bonz on Sep 29

The Red Shirt Diaries: The Conscience Of The King
By: T'Bonz on Sep 28

Couple Marries In Trek-themed Wedding
By: T'Bonz on Sep 28

Elba’s Star Trek Beyond Villain
By: T'Bonz on Sep 28

Star Trek Online: Help Design A Ship
By: T'Bonz on Sep 25

Welcome! The Trek BBS is the number one place to chat about Star Trek with like-minded fans. Please login to see our full range of forums as well as the ability to send and receive private messages, track your favourite topics and of course join in the discussions.

If you are a new visitor, join us for free. If you are an existing member please login below. Note: for members who joined under our old messageboard system, please login with your display name not your login name.

Go Back   The Trek BBS > Star Trek TV Series > The Next Generation

The Next Generation All Good Things come to an end...but not here.

Thread Tools
Old June 15 2013, 10:13 PM   #1
21 cm of Galaxy's Child

What the hell were those 21 cm wave length that all matter should resonate/fluctuate with??? I never understood that one. Is there any real scientific bearing/equivalence?
Reeborg is offline   Reply With Quote
Old June 15 2013, 11:35 PM   #2
Rear Admiral
GalaxyX's Avatar
Location: Canada
Re: 21 cm of Galaxy's Child

I'd have to watch the episode again, but from my understanding, it had to do with the frequency of the energy being absorbed by the creature.

All energy has a wavelength, as you can see in a chart of the Electromagnetic Spectrum.

the 21cm wavelength in real life has something to do with the wavelength of energy detected from hydrogen gas in interstellar space.

Not sure how that ties into the episode. I'm actually curious to watch it now.
Top Gear America: Jay Leno, Adam Carolla, Tim Allen. DONE!
GalaxyX is offline   Reply With Quote
Old June 15 2013, 11:37 PM   #3
Christopher's Avatar
Re: 21 cm of Galaxy's Child

It's a very, very bad misinterpretation of something that does have a legitimate scientific basis.

When the electrons around atoms are excited (i.e. absorb energy), they jump up to higher energy states, and then emit photons of light/electromagnetic radiation when they jump back down to a lower state. Since their states are quantized, the photons they emit always have certain specific amounts of energy, which correspond to different wavelengths of light -- the more energy, the shorter the wavelength (i.e. the higher the frequency). One of the main emission lines for neutral hydrogen atoms has a wavelength of 21.106 cm, which is in the microwave band (i.e. radio waves that are shorter than shortwave) and happens to be a wavelength that can pass through interstellar gas and dust easily as well as being able to penetrate the Earth's atmosphere. So it was the first wavelength that could be used for radioastronomy: using radio or microwaves to observe things about outer space that we couldn't detect with visible light. And since hydrogen is the most common (non-dark-matter) element in the universe, it let us discover a great deal about the shape of the galaxy and the universe beyond.

So that line about how "all matter in space vibrates in a specific radiation band" sounds like a case where the show's writers completely misunderstood what their science advisors were telling them. Yes, neutral hydrogen gives off radiation in that band, and most matter in space is hydrogen, but it's certainly not all matter, it's not the only wavelength it emits, and it's got nothing to do with vibration (that's confusing sound wavelengths with light wavelengths). I winced the first time I heard that line, and I've winced every time I've heard it since.
Written Worlds -- Christopher L. Bennett's blog and webpage
Christopher is offline   Reply With Quote
Old June 15 2013, 11:45 PM   #4
Rear Admiral
GalaxyX's Avatar
Location: Canada
Re: 21 cm of Galaxy's Child

^^^ Cool that clears up the question in my mind.

The whole vibration thing is hard for people to understand, because, exactly as you explained it, there really is no vibration in electromagnetic energy because it's not disrupting any medium, as in the case of sound waves.
Top Gear America: Jay Leno, Adam Carolla, Tim Allen. DONE!
GalaxyX is offline   Reply With Quote


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT +1. The time now is 06:32 AM.

Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
FireFox 2+ or Internet Explorer 7+ highly recommended.