Jen took out her Astronomy book and waited for class to begin.

Lee was swinging in the seat on which he claimed as his own at the start of the year. Astronomy really wasn't his thing so he prefered to stare out the window and let everyone ramble on, Llewllyn was bound to get them some points, he was a smart hufflepuff. Lee looekd around for any sign of him, he hadn't arrived yet "okay... looks lik some other hufflepuff will need to be smart since we are only 4 points away from 1000" he said to himself.

Anila walked in to take a seat. She smiled at the humming Professor, and sat down.

Erica shook her head as Professor Dainsie laughed at their questions. This term was doing things to her head, she was sure of it now, if not before. She really needed to lighten up and relax and release all that pent-up tension in her before it did worse things. She forced a small smile and started doodling on her parchment, waiting for class to begin.

Ok, so stars. We know what they look like, we've seen them many times, but what exactly are they? Who can give me a definition?

Jen raised her hand. "A star is any massive gaseous body in space. A star generates energy through nuclear fusion and emits light. All stars appear as shining points in the nighttime sky that twinkle because of the effect of the Earth's atmosphere."

Jamie realized there were many definations. She raised her hand and said, "One could be, a self-luminous celestial body consisting of a mass of gas held together by its own gravity in which the energy generated by nuclear reactions in the interior is balanced by the outflow of energy to the surface, and the inward-directed gravitational forces are balanced by the outward-directed gas and radiation pressures." Jamie then took a breath and said, "Another could any of the celestial bodies visible at night from Earth as relatively stationary, usually twinkling points of light. Or just something regarded as resembling such a celestial body."

"A self-luminous celestial body consisting of a mass of gas held together by its own gravity in which the energy generated by nuclear reactions in the interior is balanced by the outflow of energy to the surface, and the inward-directed gravitational forces are balanced by the outward-directed gas and radiation pressures," Arkee read from her textbook, squinting at the big words.

"That's not very romantic at all," she huffed.

Serena raised her hand. Stars are heavenly bodies that are made of a mass of gas that is held together by its own gravity and where it's energy is generated by nuclear reactions inside and where the energy flows out to the surface. Or simply the shiny or twinkling 'celestial' bodies that we can see from Earth after darkness falls.

Excellent! 5 points.

About 5,000 stars can be seen with the naked eye, although not all of these stars are visible at any given time or from any given place. With a small telescope, hundreds of thousands of stars can be seen. The largest telescopes disclose millions of galaxies, which may each contain over 200 billion stars. Modern astronomers believe there are more than 1 x 1022 stars in the universe (this number is very large, a 1 followed by 22 zeros). The largest stars, if placed at the Sun's position, would easily engulf Earth, Mars, Jupiter, and Saturn. The smallest white dwarf stars are about the size of Earth, and neutron stars are less than about 20 km (about 10 mi) in diameter.

All stars are composed of hot glowing gas. The outer layers of some stars are so empty that they can be described as red-hot vacuums. Other stars are so dense that a teaspoonful of the material composing the outer layers would weigh several tons. Stars are made chiefly of hydrogen and a smaller amount of helium. Even the most abundant of the other elements present in stars-oxygen, carbon, neon, and nitrogen-are generally present in very small quantities.

How far is the sun from the earth?

Kay raised her hand. "The sun varies in its distance from Earth. On average it is 149,000,000,000 meters from the Earth, or 92,600,000 miles."

Tao raised her hand. "The sun is about, on average, 147.5 million km. away from Earth. And an interesting fact since it's this weekend," she added hoping this would be really impressive. "On July 4th, the sun will be 152.6 million km. away from the Earth."

That's right, 3 points.

It appears different from the stars visible in the night sky because it is about 250,000 times closer to Earth than the next closest star.

What is that star?

Tao raised her hand again. "That would be the double star, Alpha Centauri."

Kay raised her hand. "The next nearest star is Proxima Centauri, which is more than 30 trillion km (20 trillion mi) from Earth."

Jen raised her hand. "Proxima Centauri is the next closest star. It's more than 20 trillion miles from Earth."

"Hi professor!"Ash said when he rushed in "Sorry i'm late."

He took a seat and waited for the class to begin.

A girl (previously unoticed by everyone) whispers to Ash "Don't announce late arrivals... you can have points taken off." "By the way, Im Alicia"

OOC:I'm really sorry guys, but due to a sporting committment I am going away for a few days, so I have to shut the class. I will re-open it when I return.

Yes! 3 points.

While light from the Sun takes only about eight minutes to reach Earth, the farthest stars are so distant that their light takes billions of years to reach Earth.

The color of stars-ranging from the deepest red through all intermediate shades of orange and yellow to an intense white-blue-depends directly on their temperature.

Fill this in:
The coolest stars are ____ and the hottest stars are ___.

Jen raised her hand. "The coolest stars are red and the hottest stars are blue."

The coolest are the black dwarfs, the hottest are the red giants (at least in my enciclophedia =P, those it says 'black dwarfs' don't exactly exist )

Serena raised her hand. "According to the Spectral Classification, O type stars are the hottest, and the M type are the coolest."


O - Brightest and live the shortest
B - Blue white burn bright, but not as bright as the O type
A - Less bright, a little larger than our Sun, but still burn hotter
F - Brighter than our Sun and a little hotter
G - Our Sun is a G type star
K - Dimmer than our Sun and burns longer because temperature is lower
M - Dimmest stars burn for a long time

Thats right, 2 points, and 5 to serena.

Most stars make light by several different kinds of thermonuclear fusion, a process in which the nuclei of atoms combine to form a heavier element and release energy. One of the most common thermonuclear fusion processes occurs in stars when four hydrogen atoms combine into a helium atom, releasing energy that is transformed into light and heat.

Astronomers learn about the physical and chemical properties of a star by studying the energy it emits. They can directly observe the atmosphere, or outermost gaseous layer, of the star. Astronomers can infer many of the properties of the star's interior by studying the star's atmosphere, its size, and the energy the star releases. The properties more closely related to the interior structure of the star are its mass and chemical composition. Astronomers also observe the motions of stars to learn more about star and galaxy formation.


The only visible part of a star is its gaseous outer region, or atmosphere.

How thick is the sun's atmosphere?

Anelreas raised her hand. "The region where the gas becomes so dense that it becomes opaque is the photosphere. The photosphere is about 330 km thick and lies 696,000 km from the center of the Sun."