# Astronomy Flash Cards

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1. ANGULAR MOMENTUM
• Energy of a spinning object
• = mass x velocity = radius

Keeps us moving around the sun
2. MASS
How much space i take up
3. WEIGHT
The force that acts on an object

In space you are weightless in free fall you're constantly falling toward the earch and you miss it
4. NEWTON'S FIRST LAW OF MOTION
An object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force.This law is often called "the law of inertia".
5. NEWTON'S SECOND LAW OF MOTION
Acceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object).
6. NEWTON'S THIRD LAW OF MOTION
For every action there is an equal and opposite re-action.
7. DOOMSDAY 2012
On Dec. 21, 2012, many doomsday believers fear the apocalypse — anything from a rogue planet smashing into us to our world spinning end over end.
8. CONSERVATION OF MOMENTUM
Total momentum of interacting objects cannot change unless an external force is acting on them
9. TYPES OF ENERGY
• Kinetice (motion)
• stored (potention)
10. THERMAL ENERGY
The collective kinetic energy, as measured by temperature, of the many individual particles moving within a substance.
11. Mass-Energy
E=MC2
12. UNIVERSAL LAW OF GRAVITATION
The law expressing the force of gravity (fg) between two objects given by the formula:

F=G x ((m m')/r²) Where G is the universal constant of gravitation; m is mass of the first body; m' is the mass of the second body; r is the distance between the two bodies
13. KEPLER'S FIRST LAW
• Law staing that the orbit of each planet about the
• Sun is an ellipse with the Sun at one focus.
14. KEPLER'S SECOND LAW
As a planet moves around its orbit, it sweeps out equal areas in equal times
15. KEPLER'S THIRD LAW
the square of a planet's orbital period is proportional to the cube of its average distance from the Sun, which tells us that more distant planets move more slowly in their orbits
16. WHAT IS ASTROLOGY
the study of how the alignment of the planets and stars contribute to a persons day to day life.
17. ECLIPTIC
The Sun's apparent annual path amon the constellations
Motion that is backward compared to the norm.

Example- we see Mars in apparent retrograde motion during the periods of time when it moves westward, rather than the more common eastward, relative to the stars
19. parallax
the apparent angular displacement of a celestialbody due to its being observed from the surface instead offrom the center of the earth (diurnal parallax or geocentric parallax)  or due to its being observed from theearth instead of from the sun (annual parallax or heliocentric parallax).
20. How can you make parallax easier from earth.
The Earth is 93 million miles from the Sun. Using the parallax method, as the Earth revolves around the Sun (at a speed of 67,000 mph), they measure the angle at one point and then six months later, when the Earth is exactly on the other side of the Sun, they take another measured angle. They then put the 2 angles together which makes a V shape. The point where the 2 angles meet is the distance to the star.If the Earth was say in Saturn's orbit at 900 million miles from the Sun, it would make a wider angle to the stars using the parallax method which would make it easier to estimate more further away stars.The Earth's 6 month parallax angle starts at 186 million miles wide(the totals of 93 million miles on each side of the Sun, 93mil plus 93 mil). If we were using Saturn's distances the angle would begin at 1800 million miles (900 mil plus 900 mol).
21. GEOCENTRIC
The belief that earth lay as the center of the universe
22. HELIOCENTRIC
Having the Sun as the center
23. PHASES OF THE MOON
24. WHAT MAKES POLARIS SPECIAL?
Because in the current era[17] α UMi lies nearly in a direct line with the axis of the Earth's rotation "above" the North Pole—the north celestial pole—Polaris stands almost motionless in the sky, and all the stars of the Northern sky appear to rotate around it. Therefore, it makes an excellent fixed point from which to draw measurements for celestial navigation and for astrometry. The moving of Polaris towards, and in the future away from, the celestial pole, is due to the precession of the equinoxes.[17
25. APHELION
The point at which an object orbiting the Sun is farthest from the sun
26. PERIHELION
The point at twhich an object orbiting the Sun is closes to the Sun
27. CIRCUMPOLAR STAR
A start that always remains above the horizon for a particular lattitude
28. WINTER SOLSTICE
the point on the celestial sphere, opposite thesummer solstice , at which the ecliptic is furthest south fromthe celestial equator.

the solstice on or about December 21st that marks the beginningof winter in the Northern Hemisphere.
29. SUMMER SOLSTICE
the solstice on or about June 21st that marks the beginning ofsummer in the Northern Hemisphere.

the point on the celestial sphere, opposite thewinter solstice,  at which the ecliptic is furthest north fromthe celestial equator.
30. EQUINOX
the time when the sun crosses the plane of the earth'sequator, making night and day of approximately equal lengthall over the earth and occurring about March 21 (vernalequinox or  spring equinox)
31. ROTATION
The spinning of an object around its axis
32. REVOLUTION
The orbital motion of one object around another
33. WHAT IS THE ZODIAC?
The constellations on the celestial sphere through which the ecliptic passes
34. WHAT DID KEPLER DO?
Johannes Kepler was the man who disproved Copernicus' theory that the planets orbit the sun in an circular motion. Kepler proved that the planets orbit in an oval, or elliptical, motion.
35. WHAT DID NEWTON DO?
Sir Issac Newton formulated the universal law of gravitation, which is a formula that describes the behavior of gravity. When Newton was at his apple orchard, thinking about how the moon revolves around the earth, he famously sees an apple fall. When he saw the apple fall, he thought that the moon was also "falling". With this single though, newton was able to unite the behavior gravity on Earth with gravity in space. Hence, Newton discovered that gravity is a universal force that is found throughout the universe
36. WHAT DID GALILEO DO?
Galileo was famous for inventing the thermometer, perfecting the telescope and for experimenting with gravity and pendulums (which influenced Newton's laws of motion).He also dropped all Aristotelian talk of WHY things moved, and thought more about HOW things move, through painstaking observations and measurements. Galileo also thought of things such as time, distance, and acceleration to describe how things move.

Born in Pisa, Italy approximately 100 years after Copernicus, Galileo became a brilliant student with an amazing genius for invention and observation. He had his own ideas on how motion really worked, as opposed to what Aristotle had taught, and devised a telescope that could enlarge objects up to 20 times. He was able to use this telescope to prove the truth of the Copernican system of heliocentrism. He published his observations which went against the established teaching of the Church. He was brought to trial and, although he made a confession of wrong-doing, he was still imprisoned for life. But it was too late to lock away the knowledge that Galileo shared. Other scientists, including Sir Isaac Newton and Johannes Kepler, seized its importance and were able to learn even more about the ways of the world and the heavens beyond.These early scientists' legacy continues to this day. As time goes on, we use our instruments, science, math, reasoning, and creativity to learn more about the secrets of the Universe. In this way, we are directly linked to the astronomers of centuries ago who gave us direction to discover more about the dances of the planets and the nature of the stars.
37. WHAT DID BRAHE DO?
A Danish nobleman, Tycho Brahe (1546-1601), made important contributions by devising the most precise instruments available before the invention of the telescope for observing the heavens. Brahe made his observations from Uraniborg, on an island in the sound between Denmark and Sweden called Hveen. The instruments of Brahe allowed him to determine more precisely than had been possible the detailed motions of the planets. In particular, Brahe compiled extensive data on the planet Mars, which would later prove crucial to Kepler in his formulation of the laws of planetary motion because it would be sufficiently precise to demonstrate that the orbit of Mars was not a circle but an ellipse.
38. WHAT DID ARISTOTLE DO?
He is sometimes called the grandfather of science. He studied under the great philosopher Plato and later started his own school, the Lyceum at Athens. He, too, believed in a geocentric Universe and that the planets and stars were perfect spheres though Earth itself was not. He further thought that the movements of the planets and stars must be circular since they were perfect and if the motions were circular, then they could go on forever. Today, we know that none of this is the case, but Aristotle was so respected that these wrong answers were taught for a very long time. Aristotle, outside of astronomy, was a champion observer. He was one of the first to study plants, animals, and people in a scientific way, and he did believe in experimenting whenever possible and developed logical ways of thinking. This is a critical legacy for all the scientists who followed after him.
39. WHAT DID CAPERNICUS DO?
Well over a thousand years later, Nicolaus Copernicus came up with a radical way of looking at the Universe. His heliocentric system put the Sun (helio) at the center of our system. He was not the first to have this theory. Earlier starwatchers had believed the same, but it was Copernicus who brought it to the world of the Renaissance and used his own observations of the movements of the planets to back up his idea. His ideas, including the revealation that the Earth rotates on its axis, were too different for most of the scholars of his time to accept. They used only parts of his theory. Those who did study his work intact often did so in secret. They were called Copernicans.Galileo
40. EARTH MOON SYSTEM
41. PHASES OF THE MOON
42. WHAT IS THE LATITUDE OF THE NORTH STAR IN OMAHA?
41
Zenith, which has an altitude of 90 degrees
44. WHAT IS A LIGHT YEAR?
The distance that light can travel in 1 year, which is 9.46 trillion km.
45. KNOW THE RELATIVE SIZE OF THINGS
All of it is the size of the planet
46. WHAT IS AN AU?
Astronomical Unit.

is a unit of length equal to 149,597,870,700 metres (92,955,807.273 mi)[1] or approximately the mean Earth–Sun distance.
47. KNOW DIFFERENT TYPES OF ECLIPSE FROM PICTURE
48. HOW OLD IS THE UNIVERSE?
14.6 billion years
49. WHAT IS A BLUE MOON?
A blue moon is full moon that occurs as the second full moon in a given month.