Class 3 The Universe And everything else…

Are there explosions in space? Are there explosions in space? If, so, what do you think causes them? If, so, what do you think causes them?

Universe: Everything that exists anywhere. Universe: Everything that exists anywhere. Observable Universe: The part of the Universe that we can see using the largest telescopes. Observable Universe: The part of the Universe that we can see using the largest telescopes. Most scientists think the whole universe is much bigger than the observable universe. Most scientists think the whole universe is much bigger than the observable universe.

Static: inactive: not in physical motion Static: inactive: not in physical motion Theory: The Universe does not grow or shrink over time and has always existed. Theory: The Universe does not grow or shrink over time and has always existed. Originally favored by Einstein. Originally favored by Einstein.

As early as 1918 though astronomers noticed that parts of the universe seemed to be moving away from us. As early as 1918 though astronomers noticed that parts of the universe seemed to be moving away from us. In 1929 Edward Hubble came up with a formula the showed that the farther some was away from Earth, the faster it was moving away. In 1929 Edward Hubble came up with a formula the showed that the farther some was away from Earth, the faster it was moving away.

The doppler effect is a change in frequency of a wave because the source is moving. The doppler effect is a change in frequency of a wave because the source is moving. A source moving away lengthens the wave. A source moving away lengthens the wave. A source moving closer shortens the wave. A source moving closer shortens the wave.

The sound is higher pitched as the vehicle approaches you and lower as it goes away. The sound is higher pitched as the vehicle approaches you and lower as it goes away.

Hubble saw that the further away an object was in the universe. The more its light was shifted toward the red end of the spectrum. Hubble saw that the further away an object was in the universe. The more its light was shifted toward the red end of the spectrum. Scientist could now tell how far away something was just by checking its red-shift. Scientist could now tell how far away something was just by checking its red-shift.

If everything is expanding, some scientists suggested that every at some early time must been altogether. If everything is expanding, some scientists suggested that every at some early time must been altogether. Then suddenly started expanding, something that continues even today. Then suddenly started expanding, something that continues even today.

Expansion of the universe. Expansion of the universe.

Many scientists were skeptical of the “big bang” until two scientists in 1965 stumbled across a mysterious level of background radiation while testing a new radio telescope. Many scientists were skeptical of the “big bang” until two scientists in 1965 stumbled across a mysterious level of background radiation while testing a new radio telescope. This was the leftover heat from the “big bang.” This was the leftover heat from the “big bang.”

Best estimate is between 13.5 and 14 billion years old. Best estimate is between 13.5 and 14 billion years old.

After about 300 million years after the “Big Bang” gravity started to pull the hydrogen gas together. If a large enough ball of hydrogen formed it would ignite into a star though fusion. After about 300 million years after the “Big Bang” gravity started to pull the hydrogen gas together. If a large enough ball of hydrogen formed it would ignite into a star though fusion.

Just like people, stars are born and die. Just like people, stars are born and die.

What happens to a star when it dies? What happens to a star when it dies?

A medium sized star like the sun will burn through all of its core hydrogen (in about 9.5 billion years), then shift to fusion in the outer shell. A medium sized star like the sun will burn through all of its core hydrogen (in about 9.5 billion years), then shift to fusion in the outer shell. This will cause the Sun to grow to a “Red Giant” star in about 5 billion years. This will cause the Sun to grow to a “Red Giant” star in about 5 billion years.

The sun will eventually shed its outer layers and end its life as a white dwarf star. The sun will eventually shed its outer layers and end its life as a white dwarf star. This will happen to 99 percent of all stars. This will happen to 99 percent of all stars. The outer layers will form a planetary nebula. The outer layers will form a planetary nebula.

Has a diameter that is the same as Saturn’s orbit. Has a diameter that is the same as Saturn’s orbit.

If a star is a large “blue supergiant,” like Rigel, it will end its life with a giant explosion called a supernova. If a star is a large “blue supergiant,” like Rigel, it will end its life with a giant explosion called a supernova. The remains of the star will be crushed down into a “blackhole” The remains of the star will be crushed down into a “blackhole”

A black hole is an object with such high gravity that when anything gets too close, it cannot escape and will be pulled in. This even includes light. A black hole is an object with such high gravity that when anything gets too close, it cannot escape and will be pulled in. This even includes light.

Scientists believe there are super massive black holes (perhaps a billion times the mass of the sun) at the center of most galaxies, including the Milky Way. Scientists believe there are super massive black holes (perhaps a billion times the mass of the sun) at the center of most galaxies, including the Milky Way.

At about the same time the first stars lit up. Large formation of matter were pulled together to form galaxies. At about the same time the first stars lit up. Large formation of matter were pulled together to form galaxies.

A galaxy is a collection of matter including hydrogen gas, dust and stars. A large galaxy can include a trillion stars. (That’s 1,000,000,000,000 stars) A galaxy is a collection of matter including hydrogen gas, dust and stars. A large galaxy can include a trillion stars. (That’s 1,000,000,000,000 stars)

We live in the Milky Way Galaxy. We live in the Milky Way Galaxy. We can see the edge of it in the sky. It appears as bright path called the “Milky Way.” We can see the edge of it in the sky. It appears as bright path called the “Milky Way.”

Has about 400 billion stars. Has about 400 billion stars.

Galaxies are pulled into groups by gravity. Our local group contains 30 galaxies including two other spirals. Galaxies are pulled into groups by gravity. Our local group contains 30 galaxies including two other spirals. Galaxy groups are also part of “superclusters” of galaxies. We live in the Virgo Super cluster which contains about 100 groups. Galaxy groups are also part of “superclusters” of galaxies. We live in the Virgo Super cluster which contains about 100 groups.

For decades scientists wondered if the universe would continue to slowly expand forever, or if there was enough gravity to pull it back together into a “Big Crunch.” For decades scientists wondered if the universe would continue to slowly expand forever, or if there was enough gravity to pull it back together into a “Big Crunch.”

Most recent calculations surprised scientists as neither was the case. The expansion is accelerating. Most recent calculations surprised scientists as neither was the case. The expansion is accelerating. This leads some to speculate about a “Big Rip.” This leads some to speculate about a “Big Rip.”

We will have a few minutes for you to work on your presentations then we will start. We will have a few minutes for you to work on your presentations then we will start.