Fun Space facts.

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ThirstyBarbarian

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-Venus rotates in retrograde, very slowly. Its sidereal rotation period is longer than its year at 243 and 225 earth days, respectively. The solar day as viewed from the surface is 117 earth days and the sun would rise in the west and set in the east if it was visible from the surface.

-Jupiter and Saturn have rotation periods of only about 10 hours. All that mass rotating so rapidly makes them noticably ovoid, squashed at the poles and bulging at the equator.

-Uranus was discovered entirely by accident by English astronomer William Herschel in 1781, and after realizing he had discovered a new planet, wanted to name it George's Star after George III, King of England and his patron. This didn't sit well with the international astronomical community and the planet was officially named Uranus, since he was the father of Saturn, who was the father of Jupiter. Some English organizations kept calling it George's Star until 1850.

-Astronomers pronounce Uranus "YER-ah-nus," with the stress on the first syllable and short a sound in the second syllable. I have habitually used this pronunciation after months working at Space Camp teaching kids about the solar system.

-Neptune was actually first spotted by Galileo as it moved near Jupiter relative to Earth. He was observing the moons of Jupiter and noted a faint star behind Jupiter. Whether Galileo thought it was just a star or recognized it as a planet is not known for sure, but reading his notes reveals that Galileo did notice that Neptune moved relative to the background stars.
I heard that Herschel wanted to name the new planet George’s Star, but the astronomical community said, “You can’t name it after Mad King George. He’s an a-hole!”

And Herschel objected, “Well, I can’t name it the A-Hole Planet!”

So astronomical community suggested, “Ok, how about you name it after Uranus, and people can just figure it out? Plus, this will be great fun at Space Camp, as long as no one tries to get too serious with the pronunciation. They can pronounce it yer-AY-nus and talk about the gaseous emissions coming from Uranus, the rings around Uranus, the Klingons on Uranus, sending a probe to plunge into the depths of Uranus, and so on.”

And Herschel thought that was a great idea.

Well, the next time Herschel saw King George he told him, “Hey, by the way, I discovered a new planet.”

And George asked him, “Did you name it after me?”

So Herschel told King George, “I named it after Uranus.”

”You named it after my butthole?”

And Herschel spent the next 10 years in The Tower.

Fun Space Fact!
 

Nathan

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The atmosphere on Mars is so thin that flying the Ingenuity helicopter on Mars is like flying a helicopter on Earth at an altitude of 100,000 ft.
 

kentsarff

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The Earth not only rotates, but
  • over 41 000 years, its axis of rotation oscillates between 22.1 and 24.5 degrees, and
  • over 26 000 years, its axis of rotation precesses (wobbles) a full circle (base of a cone).
If anyone knows where I can find a desk globe displaying this (like a gyroscope with an Earth model as a rotor), I want one. Why? Because for too long I was mislead by regular globes into thinking the axis of rotation was fixed in space and it irks me.
Let's talk about planning horizons.

When the Nassar High Dam was being built near Aswan Egypt, the new Lake Nassar was going to flood the temple of Abu Simbel, on the Nile near the Sudanese border. So a UNESCO-funded mega project sawed the temple into blocks and rebuilt it in a human-made "mountain" about 500 yards up the bank. The innermost rooms of the temple are properly lit at sunrise only two days a year (equinoxes, 'natch), and when the temple was rebuilt, it was positioned to be correct 5000 years in the future, based on the known procession of the earth's axis of rotation.

That's a long-term planning horizon...
 

Blast it Tom!

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I saw all of the launches from Mercury to Apollo. When 2001 came out I looked at it as a prediction of the future. As we got closer in time to the real 2001 I became more and more sure it wouldn't happen in my lifetime. I am bummed. The only hope I have left is that ET comes for a visit in my lifetime. I'm 65.
Oh, no, I'm 65 as well and I think we'll be back before then... Of course, there are some issues with the Senate err.. Space Launch System's timetable...

@Funkworks, is there some kind of right-hand rule or other convention going on there? Why couldn't Pluto be 60° and Uranus 82°??? North Pole orientation reLative to...?

Boy, that Mercury is a straight-up kind of guy!
 

mach7

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I was going to post "just like it's inhabitants" But you beat me to it!
 

Blast it Tom!

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I just did some fiddling in Mathcad, and figure again with our basketball-sized Earth, we can only live (without aid) in the first 15,000 ft or so of elevation. Which translates to .0034 inches or .085 mm. The height of Everest is probably less than the dimples on the ball.
 

boomtube-mk2

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Earth has the highest density of any known object in our solar system.
Meanwhile, Saturn would float if placed in water, some speculate that Saturn might not even have a solid core.
And I believe it was Arthur C. Clarke who conjectured that it might be possible for Jupiter's core to be a diamond the size of Earth.

The Sun has an atmosphere; an incredibly hot atmosphere but an atmosphere none the less.
Now sound can travel within an atmosphere and being that the Sun is an enormous and ongoing thermo-nuclear explosion, imagine how loud it must be.

We're talking Spinal Tap loud.
 

Blast it Tom!

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Meanwhile, Saturn would float if placed in water, some speculate that Saturn might not even have a solid core.
And I believe it was Arthur C. Clarke who conjectured that it might be possible for Jupiter's core to be a diamond the size of Earth.

The Sun has an atmosphere; an incredibly hot atmosphere but an atmosphere none the less.
Now sound can travel within an atmosphere and being that the Sun is an enormous and ongoing thermo-nuclear explosion, imagine how loud it must be.

We're talking Spinal Tap loud.
There's an XKCD for that:
1632412461207.png
 

Funkworks

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@Funkworks, is there some kind of right-hand rule or other convention going on there? Why couldn't Pluto be 60° and Uranus 82°??? North Pole orientation reLative to...?
Yes exactly. If you point your right thumb in the direction of a straight arrow... oh... there should be an arrow on each axis - and most of them would point upwards - your fingers will indicate the direction of rotation.

All angles in the figure are measured from the top vertical (from the 12 o'clock position)

I think the figure would be a notch better if the curving arrow for Venus had been drawn at the bottom. Then you'd have a neat visual trend of increasing angle from Saturn, to Neptune, to Uranus, to Pluto, and to Venus.
.
main-qimg-66a2ec05ec63b7375627853c3ea93a94.jpeg
 
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Funkworks

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Since Earth's rotational axis has an oscillation and a precession, I submit the same goes for all other planets. Maybe I'll look up these number and make them into a fun fact. I assume there's a table somewhere.
 

Grog6

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I never found that xkcd; I'm printing that. I used to sell that " upgrade" from my electronic shop.My "kit " was a potentiometer plate, labelled 11 to 20, depending on the option and a 3 cent capacitor to make it sound a bit different. :)
 

Grog6

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For really strange planetary interactions, check out James P Hogan, Cradle of Saturn, and "the Anguished Dawn"
Both awesome.
 

MetricRocketeer

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Ə ə are called "schwa", and are pronounced like a soft grunt. Like the double 'o' in "good".
Hi @jqavins and everyone else.

Actually, the vowel sound in the English-language word good does not describe the schwa sound well. A better example is the vowel sound in the English-language word but.

Stanley
 

Funkworks

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The axial tilt of Mars seems to vary from about 15 to 35 (or 45 deg, not sure yet) over a 125 000 (earth-year) cycle.

Not yet sure these numbers can be seen as "factual", but I'll try to do a little more digging soon enough.

obl_orig.jpg

6044p.jpg


This sounds important if you're going to look for water and such.

Edit: the NASA link below seems to represent the state-of-the art in efforts to determine Mars's obliquity variations. Basically: an ongoing area of research, and likely/possibly chaotic from 10 to 60 degrees, rather than a small oscillation around a few degrees like Earth. Difficult to condense into a conventional "fun fact".

 
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boomtube-mk2

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The Milky Way galaxy is so vast that there could currently be 10,000 sentient cultures thriving within it and yet they could be 10,000 light years distant from each other, including us.

It has been determined, through computer modeling, that common radio and TV signals will become so degraded in just a dozen or so light years that they will be indistinguishable from the Cosmic White Noise.
We could be receiving "Signals" from dozens of intelligent civilizations* via radio telescopes and not know it.

*Though if the first of my comments is true, then those signals would be tens-of-thousands of years old.
 
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jqavins

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Hi @jqavins and everyone else.

Actually, the vowel sound in the English-language word good does not describe the schwa sound well. A better example is the vowel sound in the English-language word but.

Stanley
From readingrockets.com, examples of the schwa sound include:
  • a: balloon
  • e: problem
  • i: family
  • o: bottom
  • u: support
  • y: analysis
From Wikipedia:
An example in English is the vowel sound of the ⟨a⟩ in the word about.
From Merriam Webster:
1: an unstressed mid-central vowel (such as the usual sound of the first and last vowels of the English word America)
2: the symbol ə used for the schwa sound and less widely for a similarly articulated stressed vowel (as in cut)
(underline added)

The 'u' in but and in cut is a "short u", denoted by ŭ.
 

boomtube-mk2

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The atmosphere on Mars is so thin that flying the Ingenuity helicopter on Mars is like flying a helicopter on Earth at an altitude of 100,000 ft.
And yet, due to Mars' low gravity Mars' atmosphere is 300+ miles deep, which is why it is slowly being reduced even more as the solar wind strips it away.
 

Adam3836

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Thought this was cool

Neutron stars are one of the possible evolutionary end-points of high mass stars. They're born in a core-collapse supernova star explosion and subsequently rotate extremely rapidly as a consequence of their physics. Neutron stars can rotate up to 60 times per second after born. Under special circumstances, this rate can increase to more than 600 times per second.

F4332698-6285-4870-B403-A76A2B2E3C16.jpeg
 

Rocketjunkie

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-Venus does not have tectonic plates. Every 10,000 years or so (IIRC, that number might be wrong) the pressure from the mantle under the crust reaches a point where the crust cracks all over the place and the planet explodes in volcanism for a while before it hardens again.
Happens 1-2 times per billion years. No water, no plate tectonics.

-The base of Olympus Mons on Mars is about the size of Arizona.
The height is also 3 times the height of the largest on Earth, Mauna Kea at about 40k feet. If both were any higher, they would exceed the strength of the rocks and slump. Mars' gravity is also 1/3 (.38) x the Earth's.

-Jupiter's magnetosphere is the largest thing in the solar system. If it was visible, it would be 2-3 times the size of the sun/moon as seen from Earth.
The sun's magnetosphere extends well beyond Pluto and the Voyagers are just passing through the Heliopause at the edge of the Sun's magnetic field.

-Saturn's rings are only 100 million years old and they will slowly fade away until they are gone in 300 million years.
They should last as long as the geysers on Enceladus keep the G ring replenished. Then the particles drift inward.

-Uranus's moon Miranda has the highest vertical cliff in the solar system at 33,000 feet, and the gravity of Miranda is low enough that you could jump off it and safely land on a cushion at the bottom.
Looks like Miranda was disrupted by impact and gently reassembled. Too small to round out so the chunks are still visible.
[/QUOTE]
 

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