By Patrick Dennis (not verified) on 27 Jan 2015 #permalink
@Patrick Dennis #1: Parallax? I guess you mean effective parallax for observers on opposite sides of the Earth; clearly single-observer parallax is infinitesimal. At opposition, Jupiter is a minimum of 4 AU (6e+8 km) from Earth, which is where any parallax would be maximized. Using a baseline of 12,800 km, the parallax is 0.213 mrad or 0.73 arcminutes. At opposition, Jupiter s angular diameter is 50 arcseconds, or 0.83 arcminutes, comparable to the parallax.
What is more significant is the speed of light! The difference in distance to Jupiter between opposition (4 AU) and conjunction (12 AU) is 1.2e+9 km. That corresponds to a light travel-time of about 4000 seconds, or more than an hour! If you used ephmerides derived at opposition, you could (near conjunction) be off by an hour in your calculation of time, or as much as 1000 km in distance!
What Happened Before the Big Bang? with Ethan Siegel Ph D bendsource.com - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from bendsource.com Daily Mail and Mail on Sunday newspapers.
Nasa s House Place – lewisboroledger com lewisboroledger.com - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from lewisboroledger.com Daily Mail and Mail on Sunday newspapers.
By Issam AhmedAgence France-PresseWASHINGTON Discovering there’s intelligent life beyond our planet could be the most transformative event in human history but what if scientists decided to collectively ignore evidence suggesting it already happened?That’s the premise of a new book by a top astronomer, who argues that the simplest and best explanation for the highly
Harvard astronomer argues that alien vessel paid us a visit jordantimes.com - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from jordantimes.com Daily Mail and Mail on Sunday newspapers.