For general discussion of topics that don't have a specific theme, questions or suggestions for research.

Moderator: daniel

Post Reply
User avatar
Posts: 126
Joined: Mon Feb 18, 2013 3:07 pm
Location: Chicago suburbs


Post by PHIon » Tue Jul 28, 2015 11:17 am

I have tried to apply daniel's method of scaling down exoplanets to moons (as demonstrated in his paper "The Colonization of Tiamat") to Kepler-452b. Here is some of the data we've been given:

The orbital period of Kepler-452b is supposed to be around 385 days. I looked around for moons in our solar system with a similar period and found Nereid, which has an irregular orbit around Neptune of about 360 days:

If you haven't read "The Colonization of Tiamat," here is daniel's method of scaling what are reported to be exoplanets going around stars down to what may actaully be moons:
11.The extreme orbital speeds of exoplanets become scaled down to moons orbiting Jupiter-like planets at the normal speeds observed in our own solar system.

As an example to item #11, we can take a conventional star with known exoplanets, such as Kepler-101, a single sun with two planets, 101-b and 101-c. 101-b orbits this star in 3.49 days, and 101-c in just 6.03 days. The fastest planet we have in our solar system is Mercury, taking 88 days. That’s a big difference. But what if we scale the star Kepler-101 down to a Jupiter-size planet? Jupiter has a bunch of moons and if it is a Jupiter-size planet, 101-b and 101-c should show similar orbital properties as some of Jupiter’s moons.
Jupiter is roughly 1/10th the size of the sun, so we can just adjust the orbital distance by a factor of 10:
101-b: 0.045 AU / 10 = 0.0045 AU.101-c: 0.0648 AU / 10 = 0.00648 AU.
So, we are looking for a couple of moons at these distances, with similar orbital periods (the period is not scaled as it is time, not spatial distance):
101-b: 0.0045 AU, 3.49 days.101-c: 0.00648 AU, 6.03 days.
Lo and behold…
Europa: 0.0045 AU, 3.55 days. Almost an exact match to Kepler 101-b.Ganymede: 0.00716 AU, 7.15 days. Just a little further out than Kepler 101-c.

To paraphrase Obi-Wan Kenobi, “that’s no planet, it’s a moon!”
"just down the road a little way, turn left, cross the drawbridge, and you will be my guest tonight."
-- directions to the grail castle

Post Reply