• First telescope used for observation:

• • Ones used by Galileo.

    • Bad, but allowed to see things such as phases of Venus, sunspots, imperfections on the moon.

• Light Collecting

• The larger the collecting area, the more you can collect.

  • 20x diameter of eyes. Collect 400x as much light. (It's an area, so you use a squared equation. 2squared)

  • Bigger telescopes increase light collecting ability to see fainter things.

     

• Resolving Power

• For example, eyes can't resolve that there are two headlights when a car is farther away. A stronger resolving power can discern detail.

• Two things determine resolving power:

  • Wavelength that you're making the observations at.

    • For example, eyes have different resolving ability, as it can see violet better than other colors. It resolves violet better than other colors due to perceived wavelength.

    • Better resolving power if the wavelength is shorter.

  • Larger Diameter

    • Animals that have larger diameter eyes have better resolving power.

The largest refractive telescope in the world

• University of Chicago. It's called Yerkes. It's a 40 inch refractive telescope.

  • Still used for astronomical research.

• First Reflecting Telescope

• Newton's Original Newtonian Reflecting Telescope was the first reflecting telescope.

 The first modern reflecting telescope

 Mt. Wilson in California. It was 100-inches

 3-meter open tubed reflecting telescope

 Kitt Peak, in Southern Arizona. It's our National Observatory

200 inch telescope

Mt Palomar

Prime focus reflecting telescope! Uses an electronic camera. You're at the focus of the primary mirror. Then you'll have a secondary mirror to bring it to bottom of telescope

6 meter telescope

• take a specialized glass, melt it, and then spin it up, get the right shape, and then cool it down as it spins. It then solidifies into the correct shape (after some cleaning.)

• A lot of telescopes are now in the 6, 7, or 8 meter size, created by spincasting.

• Largest Optical Telescope in the world:

• Keck 10 meter telescope in Mauna Kea, Hawaii.

• A segmented design.

• Create 30 smaller mirror pieces and fit them all together.

Radio detection and ranging

 1000 foot radio telescope

 Arecibo, Puerto Rico. It was built into a depression in the ground

•    Astronomers used this technology to see if astronomical objects would produce radiowaves.

• They wanted to develop a system in which they get a radio picture and see where they're coming from.

•      Visual image (A picture.)

  • Made up of pixels. PIX(picture)EL(element.)

    • A piece of the picture!

    • More pixels; more detail.

    • Pixels are made of...

      • “Color”/Wavelengths

      • Location (X,Y)

      • Brightness/How much light energy?

• Stage 1: Early Solar Nebula

•      Clouds of gas and dust, left over from the galaxies formations, etc...

• The gasses are atomic, and made of atoms and ions. If light passes through gas, VERY specific wavelengths are being absorbed. To detect gas, you need to see absorption lines if there's a source of light behind it.

• Dust is comprised of tiny particles, similar in size to the dust in your room. Dust absorbs broad wavelengths. Red travels better through dust than blue. This is due to the size of the particle relative to the wave of light. Even better with infrared.

• If it's dense enough, self-gravitation will occur. It must collapse inward. Most are being held up by gas pressure, but if self-gravitation occurs, the pressure is not enough. As it collapses down, the gas pressure goes up. The gas law is P= nRt/v.

• Stage 2: Free-Fall Collapse

• Particles move faster and faster. When things get very hot, the hydrogen ionizes, and the electrons fly out. The protons, which all have positive chargers, repel and fly apart and together, etc... Eventually, they hit together and stick. This is called fusion. Energy releases from the process.

  • The cloud uses this energy. What holds these two positives together? The strong nuclear force holds them together. Begins to flatten into a disk as it spins, caused by conservation of angular momentum.

• Stage 3:Helmholtz Contraction

•      Gravitational collapse occurs.

• Internal gas pressure slows contraction.

• Stage 4: Solar Disk

•      Gas atoms fall in.

• Disk starts to rotate rapidly.

• “Protosun” in the center heats up, stopping the collapsing.

 Accrete

•    Particles that are smaller run into smaller particles, making larger particles. These particles run into other big particles and grow bigger and bigger.

Venus

•    Extremely substantial atmosphere.

  • Much thicker than the earths.

  • Much hotter.

•   Something the size of Mars could have slammed into the earth, and the resulting particles would have accreted into the Moon.

• This chaotic period of massive planets hitting each other.

•    Earth, Venus, Mars, Mercury, etc...

  • These planets are rocky.

  • About 5 grams per cubic centimeters.

  • Made of high density materials.

• Jovian Planets:

•    .8 to maybe 2 grams per cubic centimeter.

• The composition of those objects are almost entirely hydrogen and helium.

  • The outer planets are so massive are due to where they formed, which let them be able to hold all the gasses.

• between Mars and Jupiter. Pieces of asteroid collisions in the belt sometimes come to the inner part of the solar system.

•   Objects in the outer region of the solar system (like Pluto – dwarf planet)

• Planetary Rules: (To be a planet...)

•    It must orbit its star.

• They must be massive enough to form itself into a spherical object.

• It's the “big dog” in the neighborhood.

•    Smallest planet in the solar system.

• Discovered by Percival Lowell.

• Slow rotation period.

• No seasons. Straight axis.

• Many craters.

• •    Third brightest object in the sky.

    • You can see it in the daytime sky.

  • Inferior planets go through all phases.

    • “New Venus” will transit across the face of the sun.

    • At superior conjunction, it's at the other side of the sun.

  • Venus is completely covered in clouds at all times.

    • No surface features. Relatively “disappointing” object to observe.

  • About the same size of the earth.

  • At the limit of eye's resolving power. Does not look like a “sphere.”

  • Considered Earth's “twin.”

    • Still in “habitable zone.”

    • Rocky planet. (Terrestrial)

    • Long rotation period. Venus is rotating backwards.

    • The day is actually longer than the year.

    • Axis is almost straight up and down.

    • Doesn't have any moons.

  • Atmosphere is mostly carbon dioxide. Around 3 percent nitrogen gas.

    • Also, contains sulfuric acid droplets.

  • Atmosphere is about 100x denser and more pressure than earth's atmosphere.

  • Temperature at the surface of temperature equilibrium is about 700 degrees Fahrenheit.

  • While it's unlikely that we'd convert the Earth into Venus, there is no doubt that the carbon dioxide we're pumping into the atmosphere is causing a greenhouse effect.

  • Used radio wave imaging to see what the surface looked like. Make use of radar.

    • Delay of waves bouncing back from rocky surface gives idea of surface's image.

    • Used Acrecibo telescope.

  • Sent a telescope TO Venus to get a better idea of its surface. (Magellan)

    • Maps out “strips” of Venus' surface.

  • Planetary Geology:

    • Try to understand the exterior planets, but the interior functions.

  • Lava Domes:

    • The same as the formation of Hawaii.

   

• Mars

•    Similar rotation period to Earth. (24.6 hours.)

• About a 24 degree axis inclination.

  • Experiences seasons.

• Mars has polar caps, like earth.

• Low gravity.

• Very slightly oblate.

• Two martian satellites.

• Mars has an atmosphere of 95 percent carbon dioxide.

• It is 1/100^th the density of Earth's atmosphere.

• Mars has dunes.

• Percival Lowell

  • Around 1900, used one of the largest telescopes to observe Mars.

  • Observed “canals” on Mars.

• Mars has weathering effects, like cyclones and dust storms.

• Mars has HUGE volcanoes:

  • Olympus Mons is the biggest mountain in the solar system.

• Sent a spacecraft to Mars in 1976.

  • Viking (Stayed stationary and sampled)

• 2002 Rover:

  • Pathfinder Mission

• 2005/6 Rovers:

  • Spirit and Opportunity

• 2012 Arrival:

  • Curiosity

  • Powered by radio active decay.

• Martian Moons:

 Phobos and Deimos

• The Titius-Bode Law

•    Take number 4, add 0 and divide it by 10, you get the distance that Mercury is.

• If you take a 4, add 3, and divide it by 10, you get Venus, etc...

• Take four, add 6, divide by ten, etc...

• Only quite worked for planets up to Uranus.

• Ganymede

•    Outer moons have rocks and ice, as opposed to our rocky Moon.

• Impact craters reveal hidden ice.

• Bigger than Mercury.

  Jupiter

• Callisto:

•    Same surface features of Ganymede.

• Io:

•    Size of earth's moon.

  Jupiter

Saturn

•    very extraordinary rings.

• Many pictures taken by the spacecraft Cassini which is in orbit around Saturn.

• Lowest density of any planet in the solar system.

  • Saturn would float in water.

• Experiences differential rotation:

  • Highest rotation speeds are near the equator. Further out, the rotation period is longer.

• Saturn is the most oblate planet in the solar system.

• Tilted about 30 degrees.

• One of the clear divisions of the rings are called “Cassini's Division”

  • Tiny little ring in the middle of a big gap.

    • Due to tugging and pulling of gravity from Mimas, particles are slowly moved out of the rings, creating gaps.

    • This is called 2/1 resonance.

    • Shepherding satellites can go around a thin ring and use the opposing forces to keep it together

•     A moon with a significant atmosphere.

  Saturn

•    Discovered by William Herschel.

• Visible to naked eye, but only if in extreme darkness.

• Made of very light elements.

• Rotates in about 15 hours.

• Uranus is also almost lying on its side. 97 degree tilt.

• Has a ring system.

• When atmosphere occults a star, the light from the star changes the composition and wavelengths of the light passed to the earth.

  • The occultation dips proved that Uranus had rings.

  • Very thin rings. Made of dark material.

• Has several moons.

•    Gallelio probably saw it in 1610.

• Discovered by prediction. Discovered by Mathematicians.

  • Made two almost correct assumptions:

    • Suppose there's a planet LIKE Uranus (Neptune's vitals are similar to Uranus)

    • Used Bode-Titius law.

    • Astronomer found the planet using a prediction in an hour.

    • Discovered by gravitational theory. Effect that it was having on Uranus.

• Has a “Great Dark Spot”

• Blue coloring from Methane.

• Neptune has rings similar to Uranus.