Final Flashcards
Ptolemaic Model
Each planet moves around Earth on a small circle (epicycle) that turns upon a larger circle (deferent).
Convection
Transportation of energy through the rising of hot plasma and the sinking of cool plasma.
Proton-Proton Chain
Nuclear fusion reactions by which stars convert hydrogen to helium. These reactions produce solar neutrinos.
Gravitational Equalibrium
The condition of a star in which the weight of overlying layers at each point is balanced by the total pressure at that point.
Oort Cloud
Second cometary region. The Outer limit of the Oort cloud defines the cosmographical boundary of the Solar System and the region of the Sun’s gravitational dominance. (1/4 the way to the nearest star).
Asteroid Belt
A region of asteroids located between the orbits of Mars and Jupiter.
Fusion
A union caused by heat. The merging of different elements into an ion. Nuclei combine to form more massive nucleous with the simultaneous release of energy.
Fission
The splitting of something into two parts. The nucleus of an atom splits into smaller parts, releasing a very large amount of energy.
Asteroid
Rocky leftovers from the era of planet formation that orbit the sun.
- Meteorite
- Primitive Meteorite
- Processed Meteorites
- Meteor
- A rock from space that falls
through Earth’s atmosphere. - Remnants from solar nebula.
- Fragments of larger bodies that underwent differentiation.
- The bright trail left by a meteorite.
Comet
Formed beyond the frost line, comets are icy
counterparts to asteroids. Only the ones that pass into the solar system grow trails from the sun melting them.
Hot Jupitar
A class of extrasolar planets whose characteristics are similar to Jupiter, however, with high surface temperatures because they orbit very close to their parent stars.
Trojan Asteroids
A large group of objects that share the orbit of the planet Jupiter around the Sun.
Extrasolar Planet
A planet outside the Solar System.
Doppler Effect
The change in frequency of a wave (or other periodic event) for an observer moving relative to its source. We can messure the speed of a distant object using this; by messuring the blue/redshift
Solar Neutrino
They are electron neutrinos that are produced in the Sun as a product of nuclear fusion, mainly contributed by proton-proton chain reactions.
Astronomy
Science that deals with the study of celestial objects; the physics, chemistry, and evolution of such objects; and phenomena that originate outside the atmosphere of Earth.
Sunspots
Temporary phenomena on the photosphere of the Sun that appear visibly as dark spots. They’re caused by intense magnetic activity, which inhibits convection, forming areas of reduced surface temperature.
Solar Wind
a stream of charged particles released from the upper atmosphere of the Sun. It mostly consists of electrons and protons with high energies.
Habitable Zone
The region around a star within which it is theoretically possible for a planet with sufficient atmospheric pressure to maintain liquid water on its surface.
Comet Plasma Tail
Comets sometimes exhibit two tails, one being the grey and the other usually blue. The grey one is caused by light refecting off dust that the comet is releasing, and is not always present. The blue is the PLASMA TAIL and is caused by CO2 ion emission from the melting by the sun.
Ratioactive Dating
A technique used to date materials such as rocks, usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates.
Greenhouse Effect
a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases.
Greenhouse Gases
Gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. The primary greenhouse gases in the Earth’s atmosphere are water vapour, carbon dioxide, methane, nitrous oxide, and ozone.
Io
The innermost of the four Galilean moons of the planet Jupiter and the fourth-largest moon in the Solar System. 400 active volcanoes made it the most geologically active object in the Solar System due to the tidal heating from friction in the interior as it is pulled between Jupiter and its other moons.
Planetary Rings
Rings of cosmic dust and other small particles orbiting around a planet in a flat disc-shaped region.
Ocean Ridges
Submarine mountain chains.
Kepler’s Laws
- The orbit of every planet is an ellipse with the Sun at one of the two foci.
- A line joining a planet and the Sun sweeps out equal areas during equal intervals of time.
- The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.
More distant planets orbit the Sun at slower average speeds: p^2 = a^3
p = orbital period in years
a = avg. distance from Sun in AU
(Nicolaus) Copernicus
A 1500’s Renaissance astronomer and the first person to suggest Earth was not the center of the Universe (heliocentric cosmology).
Polaris
The brightest star in the constellation Ursa Minor. It is very close to the north celestial pole, making it the current northern pole star. It’s a multiple star consisting of 3 close stars.
Retrograde Motion
Motion in the direction opposite to the movement of something else, and is the contrary of direct or prograde motion. Venus and Uranus are examples of this, orbiting in the same direction as the rest of the galaxy but turning in the opposite direction.
Apparent retrograde motion is the motion of a planetary or other body in a direction opposite to that of other bodies within its system as observed from a particular vantage point. All the planets at one time exhibit apparent retrograde motion from earth because they travel from west to east due to the spinning of Earth.
Ecliptic
The Sun seems to move against the background stars as seen from the orbiting Earth. The ecliptic is the path the path the Sun appears to be traveling through the stars in the background.
CCD
A charge-coupled device is a device for the movement of electrical charges, usually from within the device to an area where the charge can be manipulated. Used in cameras; the camera focuses light like an eye and captures the image with a detector (CCD).
Radio Interferometry
It refers to a family of techniques in which waves, radio waves, are superimposed in order to extract information about the waves; linking two or more telescopes so that they have the angular resolution of a single large one
Celestial Sphere
An imaginary sphere. All objects in the observer’s sky can be thought of as projected upon the inside surface of this sphere.
Redshift Of Light
This happens when light seen coming from an object that is moving away is proportionally increased in wavelength, or shifted to the red end of the spectrum. The light from objects traveling away from us is stretched and begins to form a hue of red.
Galactic Orbit
We make one full rotation around the center of our galaxy every 230 million years.
Precession Cycle
Earth has a
26,000 year precession cycle that slowly and
subtly changes the orientation of the Earth’s
axis.
Cylce Of Moon
29.5 days;
new (no picture)
crescent
first quarter
gibbous
full
gibbous
last quarter
crescent
(crescent to full: waxing, gibbous to crescent: waning)
Synchronous Rotation
Rotates exactly once with each orbit. The Moon does this.
- Mass
- Weight
- The amount of matter in an object.
- The force that acts upon an object.
Wavelength
The distance between two wave peaks.
Frequency
The number of times per second that a
wave vibrates up and down.
Electromagnetic Spectrum
The entire range of wavelengths of light.
What makes up atoms?
Electron clouds with a nucleus in the center.
What make up a nucleus?
Nucleoi are made of protons and electrons.
- Atomic Number
- Atomic Mass Number
- # of protons in nucleus.
- # of protons + neutrons
Phases Of Matter
- Solid (ice)
- Liquid (water)
- Gas (water vapor)
Dependent on temperature and pressure.
Three Basic Types Of Spectra
- Emission Line Spectrum
- Continuous Spectrum
- Absorption Line Spectrum
Refraction
Refraction is the bending of light when it passes from one substance into another.
Focal Plane
Where light from different directions
comes into focus.
Two Types Of Telescopes
- Refracting telescopes focus light with lenses.
- Reflecting telescopes focus light with mirrors. (most prominent)
Radio Telescope
It’s like a giant mirror that reflects radio waves to a focus.
Required Space Telescopes
- Infrared telescopes
- Ultraviolet-light telescopes
- X-ray telescopes
- Gamma ray telescopes
What are the major features of the Sun and planets?
– Sun: Over 99.9% of the mass.
– Mercury: A hot rock.
– Venus: Same size as Earth but much hotter.
– Earth: Only planet with liquid water on surface.
– Mars: Could have had liquid water in past.
– Jupiter: A gaseous giant.
– Saturn: Gaseous with spectacular rings.
– Uranus: A gas giant with a highly tilted axis.
– Neptune: Similar to Uranus but with normal axis.
– Pluto: An icy “misfit” more like a comet than a planet.
Two Main Planet Types
- Terrestrial planets are rocky, relatively small, and close to the Sun.
- Jovian planets are gaseous, larger, and farther from Sun.
Flybys
A flyby mission flies by a planet just once, cheaper than other mission but have less time to gather data.
Orbiters
Go into orbit around another world. More time to gather data but cannot obtain detailed information about world’s surface.
Probes or Landers
They land on the surface of another world and explore the surface in detail.
Sample Return Missions
Land on the surface of another world and gather samples. Spacecraft designed to blast off other world
and return to Earth.
The Nebular Theory
Our solar system formed from the gravitational collapse of a giant interstellar gas cloud—the solar nebula.
Galactic Recycling
Elements that formed planets were made in stars and then recycled through interstellar space.
Conservation Of
Angular Momentum
Rotation speed of the cloud from which our solar system formed must have increased as the cloud contracted. Solar nebula spun faster as it contracted because of conservation of angular momentum
Flattening
Collisions between particles in the cloud caused it to flatten into a disk.
Magnetic Fields
A world can have a magnetic field if charged particles are moving inside, which requires 3 things: molten interior, convection, and moderately rapid rotation.
Terrestrial Interiors
Core, mantle, crust in that order. Denser materials are found deeper.
Sun Radiation Zone
Energy transported upward by photons.
Sun Core
Energy generated by nuclear fusion.
