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zrice03
2015-Nov-26, 04:52 AM
I was idly calculating some stuff for Mars and noticed an odd coincidence:

the diameter of the Earth x the orbital period of the Earth = the diameter of Mars x the orbital period of Mars

to within about 0.05%. It's pure coincidence obviously, but I love finding these odd coincidences. Anyone else have one?

KaiYeves
2015-Nov-26, 06:51 AM
I was idly calculating some stuff for Mars and noticed an odd coincidence:

the diameter of the Earth x the orbital period of the Earth = the diameter of Mars x the orbital period of Mars

to within about 0.05%. It's pure coincidence obviously, but I love finding these odd coincidences. Anyone else have one?
On Mars, the sky is brownish-orangish during the day and blue at sunset, on Earth, the sky is blue during the day and can be orange at sunset. I always thought that was a neat reversal.

citpeks
2015-Nov-26, 04:46 PM
The width-to-length ratios of the Carolina Bays have a standard deviation of 0.045

http://cosmoquest.org/forum/showthread.php?157267-The-Carolina-Bays-are-conic-sections

Ross 54
2015-Nov-26, 04:55 PM
The rotation period of Mars is just 40 minutes longer than that of Earth. Earth's day in about 97 percent as long as one on Mars.

Arneb
2015-Nov-27, 04:37 PM
Solar eclipses, anyone? :D

Ken G
2015-Nov-27, 05:57 PM
How about, that the exact DNA code you call "you" ever happened at all?

antoniseb
2015-Nov-27, 07:28 PM
How about, that the exact DNA code you call "you" ever happened at all?
Can we please keep this thread to objects or events where there are multiple instances involved? Calling something singular like that a coincidence is derailing from the OP.

borman
2015-Dec-08, 04:06 AM
A coincidence not commented on is with the trailing quasi annual anomaly after the onset of the Pioneer Anomaly. The magnitude that is swept through is approximately equal to the Milgrom constant, a_0. At this close distance to the sun and lack of variation of orbit, neither the prescription of MOND nor MI (Modified Inertia) would work to explain the back and forth variation of acceleration spanning a_0. However the coincidence could be investigated as a de-screening and re-screening of the a_0 Dark Matter Effect signal. Effects due to gas leaks from small orientation corrections were monitored to last from 3 to at most 21 days.

Early on, there was discussion, based on a_0=cH, that might be responsible for the Pioneer Anomaly Proper but this value is around a factor of 7 too large. The annual anomaly is not a full year but varies and is more like 300 days. There have been a couple attempts to model this length of time. Jan Te Boom looked for where 300 days has orbital significance. Another author who co-wrote a recent paper with Anderson also was able to find a similarity of variation but there remains an order of magnitude problem. Also there may be an issue with the magnitude (12 units) of a suggested anomaly for Ulysses while being 80 degrees out of the ecliptic where the anomaly should be significantly less than 8 units according to the hypothesis' explanation for spiral galaxies. In this paper Anderson reiterates the tension between his 2002 analysis and the more recent Turyshev thermal analysis.

There is a way to resolve the tension. The equations both use for thermal conduction through the HGA are not strictly complete if transition metal oxides are present in the paint. Pseudogaps are known to occur at temperatures as warm as a few hundred degrees Kelvin (around room temperature). An important discovery, the paper published in Nature in 2002, from the branch of physiscs klnown as condensed matter physicis, was made where time symmetry is broken for right circular photons trying to cross a pseudogap. There will be more photons backscattered once the pseudogap transition occurs. The main Pioneer Anomaly would still find a prosaic thermal solution for the 60 watts or so that Anderson might accept. Understandably the discovery paper was not known to Anderson at the time of his 2002 paper publication. In support of this idea is the open unanswered question of how the Pioneers seem to show a late onset past Saturn while both Ulysses, orbiting between Jupiter's orbit and just outside Earth's orbit and Galileo, at Jupiter's orbit, seemed to show the anomaly much deeper inside the solar system. One property that both Ulysses and Galileo shared that is not shared by any of the four Pioneers (two are still on Earth) is that they used black paint, with ITO, rather than white paint on the Pioneers. This opens the question of whether the two closer craft had a warmer pseudogap transition than the Pioneers because of physical differences in the paint on the HGA.

Spacedude
2015-Dec-08, 04:28 AM
Ross 54 :

The rotation period of Mars is just 40 minutes longer than that of Earth. Earth's day in about 97 percent as long as one on Mars.

Add to that Mars' axis tilt is 25 degrees vs Earth at 23.5..............Mars - an abandoned Earth II experiment, nyuk.

Chuck
2015-Dec-08, 05:58 AM
Mars and Mercury have about the same surface gravity.

DonM435
2015-Dec-08, 06:41 AM
Mars and Mercury have about the same surface gravity.

They used to say that about Earth and Neptune, although the concept of "surface" is vague for a gas giant.

Ken G
2015-Dec-08, 05:30 PM
Titan has about 1.2 times the mass of air as Earth has.

LaurieAG
2015-Dec-10, 07:05 AM
It's pure coincidence obviously, but I love finding these odd coincidences. Anyone else have one?

Dark Energy = DE = 68.3%, Dark Matter = DM = 26.8%, Ordinary Matter = OM = 4.9%.

1. Calculated Matter = CM = DM + OM = OM * 31.7/4.9 = OM * 2 \pi within 3%

2. DE + DM + OM = OM * 100/4.8 = OM * 2 \pi^2 within 6%

3. DE + DM = DM * 95.1/26.8 = DM * \pi within 13%

leipzig
2015-Dec-11, 02:37 PM
The moon's rotation period is the same as the time it takes to orbit the earth.

Hornblower
2015-Dec-11, 05:18 PM
The moon's rotation period is the same as the time it takes to orbit the earth.

That's not a coincidence. It is readily explained by gravitational interaction.

tony873004
2015-Dec-11, 07:35 PM
"Back of the envelope" math is easy because of lots of constants that are almost perfect integers, etc:
g = 9.8 m/s/s (~10)
Sun Mass: 1.99e30 kg (~2)
Earth Mass: 5.97e24 kg (~6)
Sun Mass: 1047 Jupiter Mass (~1000)
Coulomb's constant: 8.99e9 (~9)
Speed of light: 2.99e8 (~3e8)

Seconds in a year: 3.15e7 (~pi x 10^7)
Moon mass = .0123 Earth mass (easy to memorize)
Sun and Moon angular size are equal.

Ken G
2015-Dec-12, 04:26 AM
Venus' rotation period is 243 days. Somehow the universe through a knuckleball.

DonM435
2015-Dec-12, 04:35 AM
More like a screwball (isn't the rotation retrograde?)

leipzig
2015-Dec-12, 04:41 AM
That's not a coincidence. It is readily explained by gravitational interaction.

Well how about that.