(A) Paper 2 Wrongs Flashcards
What is the temperature of the Sun’s core?
15 Million K
What is the temperature of the Sun’s radioactive and convective zones?
2 million K to 6 million K
What is the role of the corona and what is it’s average temperature?
High velocity solar particles interact with magnetic field and emit X rays. 2 million K
What are other objects orbiting between Jupiter and the Kuiper belt known as?
Centuars
What do scientists believe caused rings around a planet?
May be due to Moon coming too close and being ripped apart by the parent body
Compare convex and concave lenses
Convex lens: enlarge an image + viewed by another convex lens
Concave: mirror can capture light and focus it to a point where it is viewed by a convex lens
Describe a Galilean refracting telescope
- Uses a concave lens as an eyepiece
- fixed focus
- limited FOV
Describe a Keplerian refracting telescope
- Uses a convex lens
- Larger or heavier
- Focusable but photos are inverted
Describe a Newtonian reflecting telescope
- has two mirrors
- concave mirror
- another mirror up the tube at 45 degree angle
Describe a Cassegrain reflecting telescope
- reflects light onto a secondary mirror
- mirror 2 faces the primary mirror + reflects onto it but focused through a small hole behind the primary
Define aperture
The amount of light a telescope receives: diameter of its objective lens or mirror
Why is aperture important?
The larger the size of the aperture, the more light that enters the telescope, making objects brighter
What is used to determine the resolution of a telescope?
- wavelength
- diffraction of light
- quality of telescope
- contrast
- brightness
- observer’s eyesight
How is resolution calculated?
wavelength/ diameter
What is the focal length of a telescope?
How far light travels inside a telescope before it reaches a focus point
How do emission nebulae emit radiation?
Stars inside or near the nebula warm the gas through UV radiation, causing the electrons to ionise + emit radiation
Describe what happens at the red giant stage
- Slows its rate of fusion
- Lacks outward pressure needed to maintain its size
- Increases in size until it starts consuming heavier elements
- When it runs out of fuel it shrinks to a white dwarf
What are the two types of supernova?
1) Star takes mass from a giant then explodes
2) Red giants core with a mass greater than several solar masses collapses in on itself
What are the two formations of neutron stars?
1) Star between 4-25 solar masses will grow into a red supergiant, explode then form a neutron star
2) White dwarf, which can’t contain its mass through electron degeneracy and exceeds 1.4 solar masses will become a neutron star
How are black holes formed?
If the mass of the core of a star is greater than 3 solar masses, gravitational collapse occurs which forms a supernova then collapses some more to form a black hole
What are the two main theories about galaxy formation?
- Vast clouds of gas and dust collapsed gravitationally allowing stars to be formed
- Lumps of matter present in the universe clumped together under their mutual gravitational attraction to form galaxies
Where are star and globular clusters positioned concerning our galaxy?
Globular clusters: surround the halo (dusty area around the galaxy)
Star clusters: near the arms
Describe a Seyfert galaxy
- bright nuclei
- emit strongly in the IR, UV and X ray regions
- typically spiral or irregular
Describe a Quasar galaxy
- emit strongly in radio waves, UV and Xray regions
- extremely large black holes
- furthest + oldest objects we know of
- large redshifts
Why is the value of the Hubble constant significant?
It allows scientists to take accurate measurements of the Universe
Describe Hubble’s law in a sentence
How fast a galaxy moves is proportional to its dsitance
What are quasars?
Astronomical objects with high luminosity found in the centre of some galaxies and powered by gas spiralling at high velocity in a supermassive black hole
What is special about quasars?
Brightest objects in the universe
What is the temperature of CMBR?
2.7 K
What kind of matter we know about could make up what we think might be dark matter
Dark dust, black holes, brown dwarfs, neutrinos
Why do cosmologists believe dark matter and dark energy exist?
The expansion of the universe should’ve decreased after the Big Bang but it is increasing, which is evidence of some other force at play
What is X ray used to observe?
Effects of fast moving particles under a strong gravitational force that surrounds a black hole
Which part of the Sun has the highest temperature?
Corona
Which type of telescope is only found on satellites orbiting the Earth?
X ray
