Topic 11 - Exploring the Solar System Flashcards
What is the nucleus of a comet?
- The centre of the comet
- Rocky/dusty ice
What is the coma of a comet?
It surrounds the nucleus and is very thin
What are the tails of a comet?
- Ion tail, made up of charged particles, pushed by solar wind, points away from Sun
- Dust tail, made up of comet debris, very large
Where did short-period comets likely originate from?
The Kuiper Belt
Where did long-period comets likely originate from?
The Oort Cloud
Where is the Kuiper Belt located, and what is it?
It is a doughnut shaped ring of icy objects beyond the orbit of Neptune (35AU - 50AU)
Where is the Oort Cloud located, and what is it?
It is a spherical shell of billions of icy objects and could be anywhere from 10 000 AU to 100 000 AU
Where is a meteoroid found?
In space
Where is a meteor found?
In Earth’s atmosphere
Where is a meteorite found?
On Earth
What is the Frost Line?
Beyond the Frost Line, gases can condense - between Mars and Jupiter
What are the three types of meteoroid?
- Stony, silicon and oxygen
- Iron, iron and nickel
- Stony-iron
Where do meteoroids come from?
Comets, asteroids, planets, moons
How does the Transit of Venus allow us to calculate the AU?
- The transit appears at different positions on the Sun depending on viewers location
- Using the distance between the viewers, and the angle between observed transits and Venus you can find the AU
What is a parsec?
The distance at which a star would have a parallax of 1 arc second
How did water get to Earth?
From comets or asteroids
Why is the human eye limited in astronomical observations?
- It’s small aperture
- Limited sensitivity in low light
What is the purpose of the objective element of the telescope?
Captures and focuses light so that the image can be magnified by the eyepiece.
What is a Galilean telescope?
An objective convex lens and a concave eyepiece lens
- Fixed focus
- Limited FOV
- Upright images
What is a Keplerian telescope?
Two convex lenses
- Is focusable
- Inverted images
- Larger then Galilean
What is a Newtonian telescope?
A concave mirror and a plane mirror
- Eyepiece on the side of the telescope
What is Cassegrain telescope?
A concave mirror and a secondary convex mirror
- Eyepiece on the end of the telescope
What is the light grasp directly proportional to?
- The area of the objective element
- The square of the diameter of the objective element
What is the Field Of View (FOV)?
The circle of sky visible through the eyepiece, measured in degrees or arcmin
The resolution of a telescope is:
- proportional to the diameter of the objective element
- reduced by observing at a
longer wavelengths
Reflectors are better than refractors because…
- No chromatic aberration
- Focal lengths
- Long focal lengths are
best and large mirrors
are better than large
lenses
- Long focal lengths are
- Reflectors can have larger apertures than reflectors
What is an advantage of a flyby?
Sensors can measure features of bodies and send detailed images
What are disadvantages of a flyby?
They don’t return to their target so further analysis can’t occur
What is an example of a flyby?
New Horizons (Outer Solar System)
What is an advantage of an Orbiter?
Can observe the same area multiple times
What is a disadvantage of an Orbiter?
They only tell us so much.
Fuel is required to slow the probe.
What is an example of an Orbiter?
Juno (Jupiter)
What is an advantage of an Impactor?
We can analyse materials
What is a disadvantage of an Impactor?
An observation craft is needed which is more expensive
What is an example of an Impactor?
Deep Impact (comet Tempel 1)
What is an advantage of a Lander?
Can study the environment in depth.
What is a disadvantage of a Lander?
Must be built in sterile conditions and may have limited movement.
What is an example of a Lander?
Philae
