Talk:Gravitational keyhole

message: Wait- I know it's just a crappy stub right now, and needs love, but this was a red link that I thought deserved at least a stub for now. (Frankly, I'll never understand why an article that has links to it would get elected for deletion, but, then, I'm an inclusionist...) - This is a genuine term used in scientific articles to refer to a physical phenomena - why delete it? Eric 09:27, 31 October 2007 (UTC)
thread_title: Speedy Deletion

message: Why is a reference to the Little Boy bomb required under the Torino Scale section? Surely the article linked to before the note is sufficient without asking the reader to perform mental arithmetic? --Rfsmit (talk) 20:11, 4 August 2008 (UTC)
replies: text: Really doesn't make sense, and disagrees with the linked article: the Megaton article lists the energy as 15 (fifteen) kt, not 13 as in this article's note; while the Little Boy article uses a range: "It exploded with a destructive power equivalent to between 13 and 16 kilotons of TNT (estimates vary) [...]". Because of the inappropriateness and the lack of agreement, this note was deleted.--Rfsmit (talk) 21:09, 4 August 2008 (UTC)
thread_title:  Little Boy reference 

message: I'd like to see someone providing the origin of the term. It would appear to refer to the keyhole-like shape of the volume of influence; but the reference could be more vague, i.e. an object passing through a region of space "like a key into a keyhole"; or it could be even more vague, i.e. "this event unlocks a future event" (akin to a computer gaming term). --Rfsmit (talk) 20:52, 4 August 2008 (UTC)
thread_title:  Etymology 

message: I would like to see a picture.  Do keyholes appear to be arbitrarily placed?  Also, are keyholes the best spots to attempt an orbit change?  Or are keyholes  merely good locations to accurately calculate future orbits?  E.g., it may be easier to monitor a ~400 meterish region close to earth even though there might be a larger keyhole much farther away.  —Preceding unsigned comment added by 131.252.223.59 (talk) 13:42, 26 August 2008 (UTC)
replies: text: Where exactly the Keyhole is depends on the orbit/trajectory of the object. So for different objects, the Keyholes have different size, shape and location. And yes, these would be the perfect places to change an orbit, lowest energy requirement. If you have the orbit of an object and add a little bit of uncertainty and make a diagram of all possibilities in space, you have something like a ribbon or a tube going through space, getting larger as you go further away from the object. (A close flyby of another massive object will greatly increase that uncertainty, after the flyby the tube will be spreading outwards at a larger angle). If that tube hits earth, you calculate in the opposite direction, and you will get a much smaller tube that is always surrounded by your original bigger tube, and it will get smaller as you get closer to the object. Keyholes then are these locations where the rate of change in the circumference of the tube is biggest, keyholes will always be right in the middle of a close encounter with another object. The article http://en.wikipedia.org/wiki/Interplanetary_Transport_Network has a nice image that helps to visualize it, and adds some helpful background. Maybe we could use that image here, but i think we might need a more fitting one. 188.104.102.52 (talk) 15:10, 7 November 2011 (UTC)
thread_title:  Pictures 

message: I came to this entry linked from the 99942 Apophis main page and found the information in the Apophis section to be incorrect...  It was listed as a 1 in 50 chance of striking the earth in 2029 as opposed to the current estimate listed on the main 99942 Apophis page and later in the section as 1 in 45,000.  As the first and fourth paragraphs are somewhat redundant, it seems to me that the section could use some cleanup.
Vargob (talk) 17:45, 19 March 2009 (UTC)
replies: text: Done. --Rainald62 (talk) 12:33, 25 September 2012 (UTC)
thread_title:  99942 Apophis 

message: WELL WHAT IS IT? Has this article explained anything at all? The mechanics or physics of what a gravitational keyhole actually is or how it arises in terms of gravity and science? This is ridiculous.  —Preceding unsigned comment added by 81.141.147.41 (talk) 13:41, 12 February 2011 (UTC)
replies: text: I agree and have written and added a new section to the article, titled "Explanation," to clarify the concept.  Feel free to improve Jedwards01 (talk) 06:55, 23 April 2011 (UTC)
thread_title:  WHAT IS A GRAVITATIONAL KEYHOLE????? 

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thread_title:  External links modified