APOD: Moon over Makemake (2022 Dec 31)

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APOD: Moon over Makemake (2022 Dec 31)

Post by APOD Robot » Sat Dec 31, 2022 5:05 am

Image Moon over Makemake

Explanation: Makemake (sounds like MAH-kay MAH-kay), second brightest dwarf planet of the Kuiper belt, has a moon. Nicknamed MK2, Makemake's moon reflects sunlight with a charcoal-dark surface, about 1,300 times fainter than its parent body. Still, in 2016 it was spotted in Hubble Space Telescope observations intended to search for faint companions with the same technique used to find the small satellites of Pluto. Just as for Pluto and its satellites, further observations of Makemake and orbiting moon will measure the system's mass and density and allow a broader understanding of the distant worlds. About 160 kilometers (100 miles) across compared to Makemake's 1,400 kilometer diameter, MK2's relative size and contrast are shown in this artist's vision. An imagined scene of an unexplored frontier of the Solar System, it looks back from a spacecraft's vantage as the dim Sun shines along the Milky Way. Of course, the Sun is over 50 times farther from Makemake than it is from planet Earth.

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Re: APOD: Moon over Makemake (2022 Dec 31)

Post by orin stepanek » Sat Dec 31, 2022 2:47 pm

Makemakemoon100mile.jpg
Makemake! The first time I saw about this planet; I thought it was
pronounced Make make like I'm gonna make a pie! :lol2: I like Ma-ke
ma-ke better! I don't know if I marked the pronunciation correctly!
To see it has a moon is interesting! JMHO; but I would like see more
exploration of Kuper belt objects! I find this section of the solar
system to be very interesting!💫
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Re: APOD: Moon over Makemake (2022 Dec 31)

Post by GoatGuy » Sat Dec 31, 2022 2:56 pm

It is worth noting that even 50× further from Sol, the surface isn't anywhere near the temperature of the Cosmic Background radiation, either. Since temperature in kelvin is proportional to radiation to the ¼th power, we can pretty easily estimate from Earth's statistics alone. Earth receives about 1360 W/m² nominally. Makemake receives ¹⁄₂₅₀₀th that. Earth is nominally 300° K (ignoring all the rotational / diurnal bits, because we CAN say the same about Makemake in whole), and ¹⁄₂₅₀₀ to the ¼ power is ⅐th, so ³⁰⁰⁄₇ is about 42° K.

And while that's pretty darn cold, it still is a LOT hotter than the 3.2° K of the CMBR.
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Re: APOD: Moon over Makemake (2022 Dec 31)

Post by De58te » Sat Dec 31, 2022 4:31 pm

Something doesn't add up. If the Hubble Space Telescope "Spacecraft" took this picture, and as far as I know the Hubble is still in orbit around the Earth, then how can it take a picture of the night side of the mini planet when it is even farther away than Pluto?

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Re: APOD: Moon over Makemake (2022 Dec 31)

Post by Chris Peterson » Sat Dec 31, 2022 4:34 pm

De58te wrote: Sat Dec 31, 2022 4:31 pm Something doesn't add up. If the Hubble Space Telescope "Spacecraft" took this picture, and as far as I know the Hubble is still in orbit around the Earth, then how can it take a picture of the night side of the mini planet when it is even farther away than Pluto?
Hubble didn't take this picture. To the HST, these objects are just point sources. This is a piece of astronomical art.
_
hst_makemake.png
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Re: APOD: Moon over Makemake (2022 Dec 31)

Post by Fred the Cat » Sat Dec 31, 2022 4:41 pm

Who says nothing travels faster than light? Through animation you could go anywhere, as fast as you want.

Might need a pretty big computer but the sky isn’t the limit. From the comfort of your living room, I could see ever larger data sets enabling your virtual ship to sail anywhere your imagination desires. 8-)
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Re: APOD: Moon over Makemake (2022 Dec 31)

Post by orin stepanek » Sat Dec 31, 2022 5:03 pm

Fred the Cat wrote: Sat Dec 31, 2022 4:41 pm Who says nothing travels faster than light? Through animation you could go anywhere, as fast as you want.

Might need a pretty big computer but the sky isn’t the limit. From the comfort of your living room, I could see ever larger data sets enabling your virtual ship to sail anywhere your imagination desires. 8-)
Thanks for the video! but I would like to stop and explore along the way! :mrgreen: :lol2:
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Re: APOD: Moon over Makemake (2022 Dec 31)

Post by pferkul » Sat Dec 31, 2022 6:08 pm

Very nice rendering. Do we have any sense of how the sun and background starts would actually appear to a human at that location? I think our pupils would shut down because of the sun's brightness (the apparent magnitude of the sun at that distance is around -18). However, it would be easy to block the sun with your hand, and since there is essentially no scattering medium (or is the dust in our solar system enough?), would the background stars then become visible as our pupils opened up? Could the Apollo astronauts shield the sun and see background stars?

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Re: APOD: Moon over Makemake (2022 Dec 31)

Post by Chris Peterson » Sat Dec 31, 2022 6:21 pm

pferkul wrote: Sat Dec 31, 2022 6:08 pm Very nice rendering. Do we have any sense of how the sun and background starts would actually appear to a human at that location? I think our pupils would shut down because of the sun's brightness (the apparent magnitude of the sun at that distance is around -18). However, it would be easy to block the sun with your hand, and since there is essentially no scattering medium (or is the dust in our solar system enough?), would the background stars then become visible as our pupils opened up? Could the Apollo astronauts shield the sun and see background stars?
The size of our pupils only plays a small role in our accommodation to varying brightness. Most of what's going on is retinal. The problem with blocking the Sun with a hand is that it still scatters off the glass in front of you - window or helmet. But if you can fully shield yourself, you should see the stars just fine. The Apollo astronauts could see stars, but it was limited by the fact that their visors were basically dark glasses.

To the eye, the stars and Milky Way from space would look very similar to how they appear to us on the the Earth from a dark location.
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Re: APOD: Moon over Makemake (2022 Dec 31)

Post by pferkul » Sat Dec 31, 2022 7:02 pm

Chris Peterson wrote: Sat Dec 31, 2022 6:21 pm
pferkul wrote: Sat Dec 31, 2022 6:08 pm Very nice rendering. Do we have any sense of how the sun and background starts would actually appear to a human at that location? I think our pupils would shut down because of the sun's brightness (the apparent magnitude of the sun at that distance is around -18). However, it would be easy to block the sun with your hand, and since there is essentially no scattering medium (or is the dust in our solar system enough?), would the background stars then become visible as our pupils opened up? Could the Apollo astronauts shield the sun and see background stars?
The size of our pupils only plays a small role in our accommodation to varying brightness. Most of what's going on is retinal. The problem with blocking the Sun with a hand is that it still scatters off the glass in front of you - window or helmet. But if you can fully shield yourself, you should see the stars just fine. The Apollo astronauts could see stars, but it was limited by the fact that their visors were basically dark glasses.

To the eye, the stars and Milky Way from space would look very similar to how they appear to us on the the Earth from a dark location.
Neat! So if all parts of your viewing window or visor were in shadow, and there were no other bright objects in view (like the Lunar surface), then you could see the Milky Way while looking in the general direction of the sun. Also I suppose the zodiacal light would be easy to see.

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Re: APOD: Moon over Makemake (2022 Dec 31)

Post by ptahhotep » Sat Dec 31, 2022 7:32 pm

I have one criticism of the picture: MK2 is not big enough to be spherical, as depicted, it should just be a rocky body.

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Re: APOD: Moon over Makemake (2022 Dec 31)

Post by johnnydeep » Sat Dec 31, 2022 8:45 pm

Fred the Cat wrote: Sat Dec 31, 2022 4:41 pm Who says nothing travels faster than light? Through animation you could go anywhere, as fast as you want.

Might need a pretty big computer but the sky isn’t the limit. From the comfort of your living room, I could see ever larger data sets enabling your virtual ship to sail anywhere your imagination desires. 8-)
That's one impressive "warp factor"! This calculator - http://www.anycalculator.com/warpcalculator.htm - says it must beat warp factor 9.999999999999999 (using the TNG scale) by a sizeable amount, since even at that impressive warp (the highest precision it can calculate) it still takes 92 days to travel 13 Gly:

warp factor calculator.png
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Re: APOD: Moon over Makemake (2022 Dec 31)

Post by kingam6@msn.com » Sun Jan 01, 2023 3:28 am

Isn't MK2 so small that it is unlikely to be spherical as illustrated?

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Re: APOD: Moon over Makemake (2022 Dec 31)

Post by johnnydeep » Sun Jan 01, 2023 2:03 pm

kingam6@msn.com wrote: Sun Jan 01, 2023 3:28 am Isn't MK2 so small that it is unlikely to be spherical as illustrated?
Another poster above also mentioned that, so it deserves an answer, which is "yes":
https://arxiv.org/ftp/arxiv/papers/1004/1004.1091.pdf wrote:Summary: Gravitational and electronic forces produce a correlation between the mass and
shape of objects in the universe. For example, at an average radius of ~ 200 km – 300 km, the
icy moons and rocky asteroids of our Solar System transition from a rounded potato shape to
a sphere.
We derive this potato-to-sphere transition radius -- or “potato radius” -- from first
principles. Using the empirical potato radii of asteroids and icy moons, we derive a constraint
on the yield strength of these bodies during their formative years when their shapes were
determined. Our proposed ~200 km potato radius for icy moons would substantially increase
the number of trans-Neptunian objects classified as “dwarf planets”.
So, MK2, at a mere 160 km diameter (80 km radius) would seem to be much too small to be spheroidal, but I suppose it isn't impossible.
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