What are some commonly known facts that are too bizarre for you to believe to be true?
For me it is the fact that our blood contains iron. I earlier used to believe the word stood for some 'organic element' since I couldn't accept we had metal flowing through our supposed carbon-based bodies, till I realized that is where the taste and smell of blood comes from.
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A day on Venus is longer than a year on Venus. One day takes 243 Earth days, while a year takes 225.
Maybe it's not "well known", but still interesting in my opinion.
I mentioned this one to my friends the other day and it took so much convincing before they actually believed me! Definitely an interesting one. Venus also spins the opposite direction to all the other planets in the solar system, meaning the sun rises in the west and sets in the east.
I get people telling me "no, that's impossible" every time I mention this fact.
"Search your feelings, you know it to be true"
Wouldn't spinning in the opposite direction indicate that it's axial tilt is flipped or something?
The leading theory is a moon sized object hit it with enough force to spin it backwards.
The energy used to reverse the existing motion might explain why it's so slow
Ok hold up so the way I'm understanding this is that its tilt (day) is slower than it's rotation around the sun (year). Is that right or am I way off?
Yep, and as a result, the 'movement' of the sun across the Venusian sky during a day seems to change direction (I think?)
You're close. Not the tilt of its axis, but its rotation around its axis (day) is slower than its rotation around the sun (year).
Earth's axis is tilted at about 23 degrees, which causes the seasons. Venus, by contrast, is tilted only about 2.6 degrees, and thus basically doesn't have seasons in a comparable way.
Earth's axis does very slowly wobble around (precession). Over long enough time scales, this affects the seasons, and it means the North Star has not always been aligned with Earth's North - once, North pointed at a patch of black sky and the North Star was just another star appearing to rotate around that arbitrary point.
I'd imagine Venus's axis might also wobble at least somewhat, but I haven't actually looked into this at all.
Thinking about this sent me down a rabbit hole because the day and year lengths are so extremely close to each other, and Venus rotates around its axis clockwise (unlike the other planets) while spinning around the sun clockwise, and its tilt is so slight... so as it spins around the sun, it rotates just enough to keep one side facing the sun almost all the time. I ended up googling whether it was tidally locked, like the moon is to Earth (such that we only ever see one side and it never changes) - and apparently it would be, but its atmosphere is so wild that it prevents tidal locking. But it almost is. It kinda has a dark side, and a light side, like the moon, but there's just enough mismatch between the yearly rotation the axial rotation that the side facing the sun changes slowly. This is the first article I found.
From that article, it seems like the daylight hours you'd experience standing on the surface of Venus would be 117 Earth days of light, before it got dark again. So the sun would rise, and then you'd have about half a Venus year (aka about half a Venus day, too) of daylight before you'd see night again. And then it'd be night for the rest of the year. But still scorching hot because atmosphere.
Anyway this is blowing my mind a bit. I feel like I should have known this - I used to be obsessed with astronomy when I was little. Maybe I knew it once and forgot. I don't know. But dayum. Planets are cool.
Yeah the Venus makes a lap around the sun in less time than it does a rotation around itself relative to said sun's position in its sky.
I've seen this fact somewhere before, but I still am unable to grasp it in my mind
Short: It completes a full 360° of the sun before the planet itself does a full 360° spin.
A few sentences longer:
In planet Earth human terms, we have defined one day as "how long it takes the planet to do a full 360 degree rotation". Example: You spin a basketball on your finger and it does one full rotation.
A year to us is "how long it takes the planet to go around the sun". Example: You hold a basketball out in front of you and you do one full rotation.
Now, to confuse people further, read about the difference between a solar day and a sidereal day.
How does this affect its gravity?
It doesn't. Gravity is caused by mass not spin. The planet's rotation about it's own axis will create a centrifugal effect that offsets gravity, but the effect is negligible for anything rotating as slow as planets.
Interesting.
It doesn't. Gravity is related to its mass, not it's orbit or rotational velocity.
The others already said the core aspect, but to get specific: the difference between your weight on the pole and your weight on the equator differs only by like .5% or something like that. This is the difference between spinning and not spinning (centrifugal force and no centrifugal force). (And also the difference in radius, since the Earth's rotation makes it a tiny bit flatter than a perfect sphere would be)