greengolfballs
greengolfballs t1_j25hdwm wrote
Reply to comment by Bioslug in Every planet in the solar system visible in rare "planet parade" by scot816
Which didn’t include Uranus or Neptune. If you read that article, it was only the planets you can see without a telescope: i.e. Mercury Venus, (Earth), Mars, Jupiter and Saturn. Still reasonably uncommon though, especially in that exact order.
Seeing any three planets in the same part of the sky is trivial. Happens all the time..
But seeing seven (plus earth) is exceptionally uncommon. It will happen again in 2040 and after that 2854.
Neptune and Uranus have the longest orbits (165 and 84 earth years respectively) so most of the time they’re not in sync AND you’ve got to wait for the other giants and inner planets to be on the same side of the sun too, so you can understand the rarity.
A parade is not the same as an alignment by the way. An alignment is when the planets (from earth’s perspective) line up within a narrowly defined margin of one another. If that margin is one degree of arc for example, you could expect all 8 planets to align once every 13.4 trillion years. Which is to say, never, because that’s 1000x the current age of the entire universe. On the plus side, the sun will become a red giant, engulfing Mercury and Venus within that time, meaning fewer planets and thus slightly higher chances of alignment. Then again the earth will be consumed too, so, you know, c'est la mort.
greengolfballs t1_iyzl9kk wrote
Reply to comment by Bacon1884 in I made a website which features positive/inspiring news stories with no ads! by happydazenews
https://futurecrun.ch/ is your friend
greengolfballs t1_j25ibbs wrote
Reply to comment by stanspaceman in Every planet in the solar system visible in rare "planet parade" by scot816
The one earlier this year didn’t include Neptune or Uranus (which the author neglected to mention). Still counts as a “parade”, but 8 together is super uncommon. The next 8-parade (see my other comment) is in 2040 and the one after that is 800 years later.