Rock me gently, rock me slowly - Part 3

It is generally attributed that Homer wrote the epic poem "the Iliad". Basically, it's a story of the Trojan war, with its many heroes and their many exploits.

At Lagrangian points L₄ and L₅, in the Jupiter-Sun system, there exist groups of asteriods that are called the Jupiter Trojans. These asteroids are broken up into either of two camps; the Trojan camp (L₄) or the Greek camp (L₅).

One thing you notice going down the list of asteroids is the lack of names of heroines of the Trojan war, and there were many. I guess that it's that it's a continuation of "the Cassandra effect".

Rock me gently, rock me slowly - Part 2

When two celestial bodies of vastly different masses, say the Earth and the Sun, attract each other there are five Lagragian libration points, in space, were gravitational and orbital forces are in equilibrium.

  These points are abbreviated as L₁ through to L₅.



L₁ to L₃ are in direct line with the heavenly bodies. Whereas L₄ and L₅, the most stable, are on a plain of sixty degrees leading and trailing the orbit of the smaller body. Bearing this fact in mind, depending on the purpose of the mission, one of the most appropriate places to position an artificial satellite would be on or close to one of these libration points.

L₁ and L₂ are being, or will be, utilized by a number of man made probes. The Gaia mission and the Webb Space telescope are some of the projects planned to take advantage of the L₂ libration point.

As L₁ to L₃ are unstable (i.e., it tends to drift) any craft would be require a propulsion system to maintain their position. To get around the problem of how much propellant will be carried, a Lissajous orbit (click on the magnifying glass, in the link, to get a good visual) is utilized to counter this particular requirement.

My guess is that with the price of fuel and the frequency of available service stations, that an alternative method of improving mileage had to be found.

TE - Rock me gently, rock me slowly

I can only assume that Andy Kim wasn't thinking about librations when he sang "Rock me gently".

Libration is derived from the Latin, which means scales. There are many types of scales but one of most accurate for weighing is the balance scale. Nowadays, the the balance scale is mostly seen as a blindfolded maiden holding in one hand the "scales of justice"

Although "Justice is blind", there are many examples were cases are miscarried.

Rock me gently, rock me slowly

The gentle rocking back and forth of the moon, over a given time period, is called libration. Even though, the front of the Moon is tidally locked to always face towards Earth, this phenomena allows an observer on Earth to see close to 60% of the lunar surface.

The ancient Greek Deity for the moon was Selene; hence selenology, the study of the geology of the Moon. Whereas her brother, Helios, was the personification of the other celestial body, the Sun.

Since the the second lightest and the second most abundant element in the observable Universe was first discovered using a mass spectrometer on sunlight, it's only fitting that it would have the name Helium.