http://stargazer-ellie.livejournal.com/ ([identity profile] stargazer-ellie.livejournal.com) wrote in [community profile] fandomhigh2006-09-13 12:33 am
Entry tags:

Astronomy 101, Moons and Planets -- Class 2 [9/13]

Week 2 -- September 13: The Sun

Syllabus | Class Roster

Handouts:
Starmaps: North | South | East | West | Overhead

Today Ellie is wearing a black t-shirt with "Astronomers like it Messier" on it, and They Might Be Giants song "Why Does the Sun Shine?" is playing.

"The Sun is by far the brightest object in the sky," Ellie began the lecture. "It's so bright that during the day its light drowns out virtually everything else in space. The Sun is so powerful that even from the Earth, its light can damage your eyesight. So never look at the Sun directly or through a telescope.

"Life on Earth is totally dependent on the the energy it receives from the Sun. This energy is produced when hydrogen atoms inside the Sun fuse to form helium. The Sun consumes four million tons of hydrogen every second. Even so, it's so vast that our star has enough fuel to keep it shining for another five billion years. The Sun's energy output is estimated to be 386 billion, billion megawatts. So in 15 minutes our Sun radiates as much energy as mankind consumes in all forms, during an entire year.

"The Sun has been given many names over the course of history. The Greeks named it 'Helios,' the origin of the adjective 'heliocentric' (meaning centred around the Sun). The Romans referred to the Sun as 'Sol,' which is where we get 'Solar System.' Until the Middle Ages it was generally assumed that the Sun orbited the Earth. In the 16th century, Nicholas Copernicus argued that it was the Earth that travelled around the Sun. However, he was not the first person to suggest this -- the Greek Philosopher Aristarchus beat him to it by nearly 2000 years. Copernicus's view of the Solar System wasn't accepted for many years until Newton formulated his laws of motion.

"The Sun is about 4.6 billion years old and is about halfway through its main-sequence evolution, during which nuclear fusion reactions in its core fuse hydrogen into helium. Each second, more than 4 million tons of matter are converted into energy within the Sun's core, producing neutrinos and solar radiation. In about 5 billion years, the Sun will evolve into a red giant and then a white dwarf, creating a planetary nebula in the process."

She went on to talk about the solar winds and solar flares and sunspots, then assigned the handwavey homework assignment.


[ooc: Thanks to [livejournal.com profile] socksofcool for the song! SP is love for me today, since I'm in DC with my family and have no idea what my computer access will be.]

Re: Talk during class

[identity profile] justmisplaced.livejournal.com 2006-09-13 05:38 pm (UTC)(link)
"I think that would traumatise anyone," Shawn said, grinning. "Any particular reason it would affect her any more than your average student?"

Re: Talk during class

[identity profile] untouchableskin.livejournal.com 2006-09-13 05:41 pm (UTC)(link)
"Willow loves school. A lot," Marie said. "I think she'd feel personally betrayed if her school supplies attacked her."

Re: Talk during class

[identity profile] justmisplaced.livejournal.com 2006-09-13 08:32 pm (UTC)(link)
Shawn chuckled, "Well for her sake, I really hope that me saying that doesn't jinx it. Also, a little bit for my sanity, I'd rather my pencils didn't go for me."

Re: Talk during class

[identity profile] untouchableskin.livejournal.com 2006-09-13 08:35 pm (UTC)(link)
"Monster invasions are one thing," Marie agreed. "But if every day items start attacking..."

Re: Talk during class

[identity profile] justmisplaced.livejournal.com 2006-09-13 10:21 pm (UTC)(link)
"I heard about the washing machines, and doors and such acting up," Shawn looked a little weirded by that concept. "That was all pretty safe though."

Re: Talk during class

[identity profile] untouchableskin.livejournal.com 2006-09-13 10:24 pm (UTC)(link)
Marie frowned. "I think I missed all that."

Re: Talk during class

[identity profile] justmisplaced.livejournal.com 2006-09-13 10:28 pm (UTC)(link)
"Yeah, so did I. Someone mentioned it to me when they were playing freak-out the newbie at the beginning of summer." He paused then added, "It worked too... the freaking out that is. I'm so not used to sentient furnishings."

Re: Talk during class

[identity profile] untouchableskin.livejournal.com 2006-09-13 10:30 pm (UTC)(link)
"Yeah, me either," Marie said. "Then again, I've gotten used to talking about magic and demons and things."

Re: Talk during class

[identity profile] justmisplaced.livejournal.com 2006-09-13 11:23 pm (UTC)(link)
Shawn nodded in agreement, "Same here, the last year or so has been an educational experience like that. Weirdly, I still like it here. Don't know how that works."