Space Flashcards
What is a frame of reference and give an example:
A set of axes of any kind that is used to describe the position or motion of things. e.g. if you are sitting in a bus, you could use the bus as a frame of reference and describe the position and motion of the things around you
What are some observations ancient civilizations made about celestial bodies?
- The stars made unchanging patterns in the sky called constellations
- On each successive day, every star rises and sets approximately 4 minutes earlier. This means that different stars can be seen on different nights, and using these stars, people could be able to tell time and produce the first calendar
- The sun rises and sets at a different rate than the rest of the stars
- The moon rises and sets at a different rate than the rest of the stars, and it displays phases
- 5 other planets, which the ancient civilizations considered special stars, also rises and sets at a different rate than the rest
What were some ancient legends told about celestial bodies?
Jupiter was the king of the gods to the romans, the sun god Ra was carried in a boat in the sky, Ursa major was a bear running from hunters in aboriginal societies, and 3 hunters chasing 4 elk explained the Big Dipper in the Snohomish (another native American group)
How do you measure the coordinates of celestial bodies?
The angle from the north is measured clockwise to the body, using a compass, and this measure is called the azimuth. The star is then measured from the horizon, using an astrolabe, and this measure is called the altitude. These are then taken together to give a celestial body altitude-azimuth coordinates.
How do you measure the movement of celestial bodies?
You use the stars as a frame of reference, because they move very little compared to the earth and planets
What was the Earth-centered/Geocentric model and how was it changed?
Aristotle created a Geocentric model of the universe with a sphere of fixed stars surrounding the planets with Earth in the center and everything revolving around it. However, the largest problem with this model was that the planets sometimes moved in the opposite direction, but Ptolemy corrected that by creating figure 1(see document) with planets that revolved in the path of the epicycle which revolved in the path of the larger circle
What was Copernicus’s Sun-centered model?
It was the earliest form of our current model of the solar system and had a Heliocentric sun in the middle. However, it still contained epicycles
Who invented the telescope and what did Galileo do with it?
Hans Lippershey, a Dutch spectacle maker, invented the telescope in 1608. Then, Galileo made some improvements and observed the night sky with it, finding craters and mountains on the moons, sun spots moving across the sun which he concluded meant the sun was rotating, 4 “stars” going back and forth near Jupiter which Galileo concluded were orbiting Jupiter, and yet no detail at all on the stars, which meant that they were much further away than the planets. These observations, especially the discovery of Jupiter’s moons, proved that the Earth-centered model was not right
How was Ptolemy’s epicycle theory fixed?
Johannes Kepler, a German Mathematician proposed that planets travel in ellipses instead of circles, which would make the calculations correct without needing epicycles based on the observations of astronomer Tyler Brahe
What is universal gravitation?
A law by Isaac Newton that states that there is a gravitational force between anything that has mass that pulls them together
What is resolving power and what can increase it?
The clarity of an image when viewed through a telescope and a larger objective lens can increase it
What are refracting and reflecting telescopes?
They are telescopes that use a lens and mirror as an objective piece (see image 2)
What resulted when Isaac Newton used a prism to refract white light?
The light refracted into a spectrum of colors and he discovered that white light is all light
What is a spectroscope?
A device that turns white light into a rainbow
What did Joseph von Fraunhofer do?
He discovered spectral lines, dark lines that resulted from the spectrum that came from when he pointed a spectroscope at the sun
What were the 3 types of spectrum?
- Bright line spectrum caused when gas is heated under low pressure and it results in (see image 3)
- Continuous spectrum caused when gas is heated under high pressure, liquid is heated or solid is heated and it results in (see image 4)
- Absorption spectrum caused when gas is heated under high pressure, liquid is heated or solid is heated and the light passes through cooler gas. The gas absorbs some of the colors, resulting in (see image 5)
What is spectroscopy and who helped found the study?
Spectroscopy is the study of the spectrums of certain substances and was founded from Gustav Kirchhoff and Robert Bunsen’s discoveries on the different spectra of different elements and the 3 types of spectra
How do diffraction gratings work?
The two-slit experiment by Thomas Young revealed that the crests and troughs of light waves can cancel each other out based on the wavelength(color) of light. This results in a spectrum forming, one more detailed than that of a prism and is used in many spectroscopes today.
What is spectral analysis?
Using the spectrum from an object and comparing it with spectra from various elements to find out what elements are in that object
What discoveries were made with spectroscopes and better telescopes?
William Herschel discovered URANUS and Gerald Kuiper discovered methane gas in Titan and 2 more of Uranus’s moons
What is the doppler effect?
It is when an object is moving, the light/sound wavelengths change. In the case of light, if an object is moving away, it is called red-shifted. If it is moving closer, it is called blue-shifted
How do combining telescopes work?
A computer takes the images from 2 different telescopes to create the equivalent of one telescope the size of the distance between the 2. This technique is called interferometry and was first performed using radio telescopes
What are adaptive optics?
The use of a computer to prevent blurring caused by the earth’s atmosphere while using a telescope
How would an astronomer find the distance to a star?
Triangulation/ parallax technique, where astronomers wait 6 months for another reading for accuracy
What units did astronomers create to handle the size of space?
AU(distance from earth to sun) and light year(distance light travels in a year)
What are the types of electromagnetic radiation?
Radio waves, microwaves, infrared, visible light, UV, x-rays and gamma rays
What did Karl Jansky do?
He discovered radio waves coming from space(by observing the rising and setting of the objects and radio waves at the same time) that would interfere with phone calls
What did Grote Reber do?
He looked further into Jansky’s discoveries and found that particular spots in the sky were giving off more radio waves than others and called these spots radio objects
Why were radio telescopes invented?
Visible light could be blocked by dust clouds in space
How could radio telescopes’ images be transmitted into an actual image?
Needles and dials on the telescope could detect the strength of the wave, and once a computer got hold of all the data, it would assemble the radio waves and color based on intensity
