The Cellar  

Go Back   The Cellar > Images > Image of the Day

Image of the Day Images that will blow your mind - every day. [Blog] [RSS] [XML]

Reply
 
Thread Tools Rate Thread Display Modes
Old 09-26-2007, 09:11 AM   #1
Undertoad
Radical Centrist
 
Join Date: Jan 2001
Location: Cottage of Prussia
Posts: 31,423
September 26, 2007: Geostationary satellites



This was an Earth Science Pic of the Day a few days ago.

This is 8 and a half hours of an open shutter pointed at the sky. Now,
that makes clear what the trails are - stars, captured as they move
across the sky while the earth rotates. But then, the dots that don't
have any trail are geostationary satellites, in geostationary orbit.

They don't have any trail because they move along with the rotation
of the Earth. They orbit at exactly the equator. That means stationary
dishes on Earth can "see" them at all times, which is why there are so
many of them. People don't want to move their dishes!

So if you follow: the camera is stationary on Earth, except that it's not
stationary at all; it's moving with the rotation of the Earth. The
satellites appear to be stationary in the picture, but that's only
because they are moving in exact harmony with the motion of the
camera. And the things that appear to move completely across the
image are stars, entirely stationary.

Well, except that they probably aren't -- but with our short span of
attention, our 70 years, we can't sit around long enough to notice
that motion... we can't perceive it.

So why does XM Radio have three satellites while Sirius appears to
have none? Sirius' satellites use a different type of orbit, a Tundra orbit.
This allows two of their three satellites to be visible to all of North
America at any given time.
Undertoad is offline   Reply With Quote
Old 09-26-2007, 09:43 AM   #2
theotherguy
no not that other guy, the other one
 
Join Date: May 2007
Location: TN
Posts: 640
We need more Directv satellites.
theotherguy is offline   Reply With Quote
Old 09-26-2007, 11:27 AM   #3
barefoot serpent
go ahead, abbrev. it
 
Join Date: Jun 2005
Location: Lawrence, KS
Posts: 2,623
Now I know why XM radio is always playing ZZ Tops LaGrange.
__________________
Chooses rowing vs. wading
barefoot serpent is offline   Reply With Quote
Old 09-26-2007, 12:04 PM   #4
Trilby
Slattern of the Swail
 
Join Date: Jul 2004
Posts: 15,654
This is too complicated and 'boy' looking for me to know or care what it is. It's some kind of "graph" that employs the ugliest green color in the world so it is not worth my attention.

How come there are no GIRL-focused IotD stuff like shoes or diamond rings or self-tanning products on the Cellar? Ever ask yourself that, UT?
Trilby is offline   Reply With Quote
Old 09-26-2007, 12:08 PM   #5
Flint
Snowflake
 
Join Date: Mar 2006
Location: Dystopia
Posts: 13,136
Actually, Brianna, that's a close-up of the skidmarks you left when you dragged your butt across the carpet.

The labels pinpoint different things you've had for dinner recently.
__________________
******************
There's a level of facility that everyone needs to accomplish, and from there
it's a matter of deciding for yourself how important ultra-facility is to your
expression. ... I found, like Joseph Campbell said, if you just follow whatever
gives you a little joy or excitement or awe, then you're on the right track.

. . . . . . . . . . . . . . . . . . . . . . . . . . Terry Bozzio
Flint is offline   Reply With Quote
Old 09-26-2007, 12:30 PM   #6
Trilby
Slattern of the Swail
 
Join Date: Jul 2004
Posts: 15,654
Oh! Thanks, Flint! I knew it was something you'd know about!
Trilby is offline   Reply With Quote
Old 09-26-2007, 12:45 PM   #7
BigV
Goon Squad Leader
 
Join Date: Nov 2004
Location: Seattle
Posts: 27,063
Quote:
Originally Posted by Brianna View Post
This is too complicated and 'boy' looking for me to know or care what it is. It's some kind of "graph" that employs the ugliest green color in the world so it is not worth my attention.

How come there are no GIRL-focused IotD stuff like shoes or diamond rings or self-tanning products on the Cellar? Ever ask yourself that, UT?
Did you just volunteer for IotD-er of the month duty? Cause we're looking for one.
__________________
Be Just and Fear Not.
BigV is offline   Reply With Quote
Old 09-26-2007, 12:52 PM   #8
spudcon
Beware of potatoes
 
Join Date: May 2007
Location: Upstate NY, USA
Posts: 2,078
Has anyone noticed several of the star tracks suddenly winked out? Is the sky falling?
spudcon is offline   Reply With Quote
Old 09-26-2007, 04:19 PM   #9
hampor
Colloquialist
 
Join Date: Jul 2003
Location: SiliValley
Posts: 75
End of the Star

Quote:
Originally Posted by spudcon View Post
Has anyone noticed several of the star tracks suddenly winked out? Is the sky falling?
That's just where the star happened to be when the exposure started or stopped.
hampor is offline   Reply With Quote
Old 09-26-2007, 04:49 PM   #10
BeltNah
Regulator of Squalor
 
Join Date: Feb 2007
Location: Sydney, Australia
Posts: 37
Help

Where do you put suggestions for IotD?
BeltNah is offline   Reply With Quote
Old 09-26-2007, 05:18 PM   #11
Undertoad
Radical Centrist
 
Join Date: Jan 2001
Location: Cottage of Prussia
Posts: 31,423
Send as links or attachments with all relevant info to undertoad @ cellar dot org.
Undertoad is offline   Reply With Quote
Old 09-26-2007, 05:46 PM   #12
BeltNah
Regulator of Squalor
 
Join Date: Feb 2007
Location: Sydney, Australia
Posts: 37
Thanks
BeltNah is offline   Reply With Quote
Old 09-26-2007, 07:47 PM   #13
Sarasvati48
Mystical Miscreant
 
Join Date: Sep 2006
Posts: 46
Damn...there are still women who play that "I'm too dumb to understand because I'm a girl..." game? I truly hope that was sarcasm...
Sarasvati48 is offline   Reply With Quote
Old 09-26-2007, 07:51 PM   #14
Trilby
Slattern of the Swail
 
Join Date: Jul 2004
Posts: 15,654
Quote:
Originally Posted by Sarasvati48 View Post
Damn...there are still women who play that "I'm too dumb to understand because I'm a girl..." game? I truly hope that was sarcasm...
um...what do you mean by that?
Trilby is offline   Reply With Quote
Old 09-26-2007, 10:09 PM   #15
aero geek
Guest
 
Posts: n/a
Where are the GPS satellites?
  Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes Rate This Thread
Rate This Thread:

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 -5. The time now is 10:55 AM.


Powered by: vBulletin Version 3.8.1
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.