Karteikarten
Astronomy
Karten in diesem Stapel (48)
- 1What is a Globular cluster?A group of old stars in the halo of the milky way (exam wants inside bulge)
- 2What stars are found in the centre of galaxies?Densely packed stars futher along in their life cycle than those in the spiral arms, but younger than stars in globular clusters.
- 3What stars are found in the spiral arms of galaxies?Very young stars being formed from gas and dust formed at the end of other stars' lives.
- 4How wide is the milky way?30kpc
- 5Label this Hubble tuning fork diagram
- 6What is an irregular galaxyA galaxy which does not conform to the other classified types.
- 7What type of galaxy would an SBb classified galaxy be?A Spiral-bar galaxy with relatively tight spiral arms.
- 8What are active galaxies?Galaxies which are giving off radiation. They have an Active galactic nucleus (AGN). Their different behaviours allow them to be classified into different groups.
- 9Give properties of Quasars and Blazars.Quasars are the brightest objects known in space, starlike in appearance, these Active galaxies emit extremely bright light from the nucleus. Blazars are like Quasars, but closer and less emittant of light.
- 10Which AGs emit Radio frequencies?Quasars and Blazars.
- 11Which AGs emit X-rays?Seyfert galaxies and Quasars.
- 12Which AGs emit Gammar rays?Some Blazars with powerful emissions.
- 13Describe the structure of an active galaxy.Galaxies with a black hole at the centre which is far bigger than normal. The black holes produce jets of high energy particles along the axes of the super-massive black hole at the centre.
- 14What is a cluster?A group of galaxies- usually around 30- relatively close together.
- 15What is a supercluster?A large group of galaxies which are very far apart but are still in range to interact gravitationally.
- 16What is an absorption line? How do we use them to classify distant objects?An absorption line is a gap of no colour when light from distant objects is refracted on Earth. The gaps are caused when gasses in an object's atmosphere absorb some of the wavelengths of light in the electromagnetic spectrum, and since we know how different gasses absorb different wavelengths, we can classify the different objects and their composition.
- 17How can absorption lines be used to show the radial velocity of a distant object?The light from distant objects is slightly blue or red shifted, depending on the speed it's moving and the direction it is moving in. When refracting the light from distant objects, the absorption line may be left or right of where they are expected to be in the spectrum. If the line is further right, the light is red shifted- showing the object is moving away. Further right from the expected position the line is, the more red-shifted, and therefore moving faster. Left is the same, but for blue-shifting.
- 18What do the letters in this equation represent? (Give measurements)λ = new wavelength (nm)
λ0 = normal wavelength/ not moving (nm)
v = radial velocity (km/s)
c = speed of light (300,000 km/s)
- 19What is dark matter?Matter which gives off no light or radiation, and is the reason we cannot see infinitely into the distance of space.
- 20What is the observer's zenith?An imaginary line going directly overhead of the observer.
- 21To what angle is the Earth's axis tilted from the ecliptic?66.5° (23.5 away from 90°)
- 22What is culmination?The highest point in the orbit of an object around Earth relative to the position of the observer. (The time at which the object crosses the observer's meridian)
- 23What is the observer's meridian?An imaginary line going from the north to south pole, through the observer marking their longitude.
- 24What are the latitudes of the two tropics?Cancer: 23.5°N
Capricorn: 23.5°S - 25Give sources of light pollution.Floodlights, street lamps, security lamps, lights above car parks and shopping centres.
- 26What is the observer's horizon?The imaginary plane that meets the observer at a tangent to the earth's surface. (A line that meets the land/sea over the horizon relative to the user's position.)
- 27Outline key points for Eratosthenes.Stick in ground in Syene did not cast shadow, but at the same time a stick in Alexandria did cast a shadow. At
Alexandria, the sun's position at noon was 7° overhead- 1/50th of a circle. Syene was 790km further south than Alexandria. 790*50 (*50 for 360°)= 39500km- Earth's circumference. - 28Give composition of gasses in Earth's atmosphere.78% nitrogen, 21% oxygen, 1% argon and water vapour and 0.04% carbon dioxide.
- 29What does the atmosphere do to protect us/ help us?It absorbs harmful solar UV radiation, and harmful X-rays and gamma rays. It also regulates the temperature, provides oxygen for us to breathe, and protects us from asteroids in part- the majority of them burn up before hitting the ground.
- 30What problems to astronomers does the atmosphere cause?It refracts light from stars coming in making them appear to twinkle and reducing the resolution, causes the selective scattering of blue light making the sky blue and making daytime observing impossible, and it absorbs the majority of electromagnetic radiation from space making distant observations harder.
- 31What is infra red radiation absorbed by?Water vapour, CO2 and methane
- 32What is UV radiation absorbed by?Ozone and oxygen.
- 33What are X-rays and gamma rays absorbed by?Oxygen and nitrogen.
- 34Explain the relationship between the difference in size of the mirror/lens of two telescopes and the difference in the amount of light they collect e.g. 10-meter and 2-meter telescopes(Size of larger telescope(m) / size of smaller telescope)^2 is how many times greater the amount of light the larger telescope collects
e.g. 10/2=5 5^2=25 the 10 meter telescope collects 25x more light that the 2 meter. - 35Explain the discovery of the Van Allen belts.Inner: The Geiger counter on explorer 1 picked up readings of radiation around Earth. These readings were confirmed by sputnik 3.
Outer: similar process on the pioneer 3 probe and confirmed by pioneer 4. - 36Describe the nature of the Van Allen belts.Two doughnut shaped rings of spiralling high-energy particles held in place by the Earth's magnetic field.
- 37Describe the formation of Rilles and wrinkle ridges.Rilles are straight or smoothly curved trenches caused by lava flows. Winkle ridges are ridges formed when the molten lunar surface cooled and buckled, contracting and forming long ridges.
- 38What is an inferior planet?A planet which is closer to the sun than Earth.
- 39What is a superior planet?A planet which is further form the Sun than Earth
- 40What is greatest eastern/western elongation and which planets are best observed at these points?When the planets are furthest from the sun in the sky. The planets best observed at this time are Venus and Mercury.
- 41What is opposition and which planets are best observed at these positions?Opposition: When planets are directly opposite the sun in the sky and at their closest to Earth. Superior planets such as Mars are best observed at opposition.
- 42What is conjunction?Conjunction is when planets are on the opposite side of the Sun to Earth
- 43What is Occultation?When an the view of an object in space is blocked by another object.
- 44What is transit?When a planet's orbit causes it to go in a path over the Sun.
- 45Describe the structure and composition of comets.Balls of rock and ice that form tails in the course of their highly-elliptical orbits around the Sun.
- 46Give purposes of ALSEPs on the moonTo analyse and monitor: the structure of the moon's interior; the composition and pressure of the lunar atmosphere; the intensity and direction of the solar wind; minute changes in lunar gravity; lunar dust and thermal and electrical properties of the lunar sub-surface.
- 47Describe the giant impact hypothesisYoung Earth was struck by a Mars-sized object (Theia) in an off-centre collision. Theia and a large portion of Earth melted and merged, and a huge amount of debris was thrown out into Earth's orbit. This cooled and became the moon.
- 48Give support for the giant impact hypothesisOxygen isotopes found in Moon rock had a similar relative abundance to Earth rocks- showing they formed at similar distances from the sun. Also the lack of water on the moon supports a high energy impact which would vaporise the water, and moon rocks were rich in minerals which would be found in magma predicted by the giant impact hypothesis.
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- Karteikarten am Astronomy, erstellt von Ben Levett am 12/02/2015.
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- Ben Levett
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