Wikipedia:Reference desk/Archives/Science/2017 November 13

= November 13 =

Planet Venus and Jupiter conjunction.
How far apart are these two planets as we see them today. Their apparent closeness looks amazing but what's the truth. Richard Avery (talk) 08:52, 13 November 2017 (UTC)
 * Stellarium tells me that the separation right now is about 15 arcminutes, about half the angular diameter of the moon. --Wrongfilter (talk) 09:10, 13 November 2017 (UTC)
 * About 833,500,000 kilometres: they have lined up because Venus is between Earth and the Sun, and Jupiter is roughly on the opposite side of the Sun to both Venus and Earth. . They are not really close - just in line with each other. Wymspen (talk) 09:32, 13 November 2017 (UTC)


 * Thank you Wymspen, exactly what I wanted. Sorry Wrongfilter I did not make my question quite clear enough. Richard Avery (talk) 15:08, 13 November 2017 (UTC)


 * The Daily Telegraph feature Night Sky in November mentioned the distance "half the diameter of the moon" but didn't mention the arcminutes - but then the moon is half a degree wide and it moves through a distance equal to its own diameter every hour.  It was a cloudless morning, and the moon was up for comparison.   I have a wide uninterrupted view down to the eastern horizon and I was out an hour before sunrise - but I forgot to look.   As far as separations go, every so often there is an occultation of a bright star by the moon (occultations of planets are far rarer).   The latest was of Aldebaran between 02:30 and 03:21 (GMT) on 6 November.   The distance here is many light years.   It happened to be cloudy, but even if it hadn't been I would have missed it because although the feature covers the whole month it is published on the first Monday. 82.13.208.70 (talk) 15:31, 13 November 2017 (UTC)


 * One of the most spectacular sights I have seen was a conjunction some 10+ years ago of Venus, Jupiter, and the crescent Moon shortly after sunset. Since you knew the focus of the crescent moon was the sun, by definition, and that Venus, the Earth, and Jupiter were all in the plane of the Zodiac ecliptic you could actually see the solar system in three full dimensions, rather than just as dots on a field.  It was awe-inspiring. μηδείς (talk) 22:44, 13 November 2017 (UTC)


 * Sorry to nitpick but technically the zodiac's the band where the planets can be (+/-8+°) and the plane's the ecliptic. Sagittarian Milky Way (talk) 03:46, 14 November 2017 (UTC)


 * Not at all, that's an important and highly relevant correction, thanks. μηδείς (talk) 03:55, 14 November 2017 (UTC)


 * Ha!  I see Jupiter and Venus rose at six o'clock, which explains why I didn't see anything.   Small nitpick:  Medeis is referring to this .   An added bonus is that the moon passed in front of Venus at 16:15 (GMT) on the Monday night, 8 December 2008.   Now, if the three luminaries really had all been on the ecliptic they would have been in a straight line.   The moon is only on the ecliptic when eclipses occur (hence the name).   You can see from List of solar eclipses in the 21st century that she wasn't there on that occasion. 82.13.208.70 (talk) 11:35, 14 November 2017 (UTC)


 * I did also see the 2008 conjunction, but the crescent moon was not between and above the two on that occasion. The conjunction I am thinking of was in 2003 or 2004 IIRC and definitely not in Decemeber, and the moon was visible between but above the two planets, i.e., above the ecliptic. μηδείς (talk) 16:36, 14 November 2017 (UTC)


 * The moon is only on the ecliptic when eclipses occur (hence the name). Not quite. The ecliptic is where eclipses can happen. The moon crosses the ecliptic twice a month; an eclipse happens if that crossing coincides with a syzygy. —Tamfang (talk) 08:35, 15 November 2017 (UTC)


 * Whats so special about planetar "conjunctions"? They already happened a million times and they are not even interesting for a Hohmann Transfer. The only "profession" that finds interest in them is Astrology aka Pseudoscience. --Kharon (talk) 13:35, 14 November 2017 (UTC)
 * They are beautiful. ←Baseball Bugs What's up, Doc? carrots→ 15:11, 14 November 2017 (UTC)
 * [ec] μηδείς has already explained that to you. HenryFlower 15:12, 14 November 2017 (UTC)
 * Humans have emotions and an appreciation of aesthetic concerns. That's why they are special.  -- Jayron 32 15:27, 14 November 2017 (UTC)
 * Humans have emotions -  Tigraan Click here to contact me 15:32, 14 November 2017 (UTC)


 * Of course I have seen conjunctions many times, and they are not beautiful in the sense of a flower or a colorized Hubble image, but this one was spectacular. I am a particularly visual thinker, and given one could see the Earth, Venus, Jupiter, (and the sun which had set), but whose position was obvious, defined a plane, and the moon was above that plane, instead of some dots on the flat sky, it was immediately clear to me that I was seeing a portion of the solar system in three dimensions, which is not normally obvious, and is a very rare event. μηδείς (talk) 16:36, 14 November 2017 (UTC)