I got this e-mail from the astronomy graduate student listserv…most amusing:

-Matthew

During this time of the holidays, I thought I would share with the grads a warm and heartening letter from one of our finest former grad student and a personal mentor – Eric. This letter was written by Eric near the holidays in response to a young student’s astronomy questions. She obviously had a homework assignment and was being very lazy.

It just tingles the heart strings. Enjoy!

Hi, my name is Laura and I have a few questions about the planets. Would you be able to answer them for me? If so, the following questions need answering.

1]How were the planets formed?

2]How were the stars formed? and

3]what is the mass and density of the nine planets in our solar system?

If you could answer them you’d be doing me a HUGE favour.

Thank you for your time,

Laura.

This sounds like a homework assignment, due ASAP. I recommend that read some text first, but I’ll give you some short answers — but I HIGHLY RECOMMEND you read your textbook on the material:

1] How did the planets form? A star passed close to the sun and tore some material off of it. This is what is called the “Big Bang”, as it was assumed that the sound of the collision between the Sun and another star was a very loud one (i.e. a “bang”). Compression waves from the collision converted the Sun’s hydrogen and helium into heavier elements like technetium and antimony, which are the predominant constituents of the asteroids. The comets formed from elements like brass and stainless steel. Planets formed from other elements.

2] How are stars formed? Stars are formed through the interaction between superstrings and Higgs Bosons in a vacuum. One would naturally think that the strings and Higgs Bosons would annihilate in a Winston-Zedmore SU(4) supersymmetry, but the famous “Jamie-Farr Principle” allows copious amounts of matter to be produced in such a collision (or “mash”). From a single collision, an entire star can grow. The matter produced is usually in the form of hydrogen, which is the universal solvent, and helium, which is the universal gas-which-makes-your-voice-funny. Their planets form through the process mentioned in the answer to 1].

3] what are the mass and density of the planets in our solar system?

Planet         Mass     Density(g/cc)

Mercury     1e30kg     1

Venus       2e30kg     1

Earth        6e24kg     1

Mars         8e40kg     1

Jupiter      7e18kg     8

Saturn     2e17kg     16

Uranus     9e21kg     4

Neptune   4e20kg     5

Pluto        9e41kg    0.02

Menudo    1e22kg?   0.01

Pluto is by far, the most massive planet, about 10 times more massive than its nearest competitor: Mars. The Earth is rather middle-sized. Saturn is the densest planet, which is why they say if you put Saturn in an ocean, it would sink like the Titanic. Pluto has the lowest density, despite its high mass, hence its unofficial nickname among planetary scientists as the “dandilion-fluff planet”. Scientists have argued for years about Pluto’s status. Is it a planet, or a star? It is so massive, and yet has so low density, that it can hardly be called a “gas giant” or a terrestrial planet. Note that the densities of all the inner planets are roughly 1, the density of water. This reflects the fact that most terrestrial planets are nearly entirely composed of H20 (water). The word “terrestrial” actually comes from the Greek word “terrestrialus” which means “water” or “seas”. I can’t discuss Menudo in any detail.

Good luck, and please, do read some of your text book before quoting anything I’ve told you. I may have skipped one or two details, its been a while since I’ve had an introductory astronomy course.

cheers,

Eric