Astro Final Extra (6/6/23) Flashcards
(46 cards)
1
Q
moons of jupiter: number
A
95 moons orbiting Jupiter
2
Q
moons of jupiter: Galilean moons
A
4 largest: Io, Europa, Ganymede, Callisto
3
Q
moons of jupiter: Io
A
- bigger in size to our moon
- Voyager 1 discovered 8 active volcanoes in 1979, later over 150 were discovered
- surface is the youngest in the solar system since its continually being remade by volcanoes
- Pele Volcano: spews lava 200 miles above the surface of Io
4
Q
moons of jupiter: Europa
A
- the surface is mostly water ice a few km thick, beneath the crust is a layer of liquid water (maybe 100 km deep)
- Ice Floes: jumbled surface
- Lake Vostok, Antarctica: 2-mile thick ice covering liquid water that has been untouched for millions of years
5
Q
moons of jupiter: Ganymede
A
- largest moon in the solar system (larger than Mecury)
- Nicholson Regio: diagonal band in a cratered surface form a flow of ice like a river
6
Q
moons of jupiter: Callisto
A
- dark and dusty surface is the oldest among the Galilean satellites
- mostly made of ice and most heavily cratered surface in the solar system
- white ice indicates there is water ice under the surface
- Valhalla Crater: impact from a crater and if it had hit faster it would have split Callisto apart
7
Q
moons of saturn: number
A
85 confirmed moons and now has 145 (as of May 12, 2023)
8
Q
moons of saturn: Phoebe
A
rotates and orbits backwards
9
Q
moons of saturn: Iapetus
A
bright white snow surface, brown parts are dust and debris around Saturn
10
Q
moons of saturn: Enceladus
A
small enough to fit comfortably in within the length of the UK, has geyers that spew jets off its surface in water-ice
11
Q
moons of saturn: Titan
A
- has its own atmosphere because it’s so cold
- a pressure of 1.5 times higher than the Earth’s
- 10x more gas, 10x higher in altitude than the Earth’s
- sunlight reflecting from a lake of methane
- Huygens lander: took 2.5 hours to descend through the thick atmosphere and then only survived for another 70 minutes
12
Q
rings of Saturn
A
- made up of tiny particles of water ice (similar to snowballs)
- extremely thin
- only 200 million years old
- Roche limit: all the jovian planets have rings
13
Q
moons of Uranus
A
- 6 moons
- unstudied
- Miranda: primarily water, hydrocarbon, methane and ammonia ices
14
Q
moons of Neptune
A
- triton: orbiting the wrong direction
15
Q
asteroid belt
A
over 700,000 asteriods between Mars and Jupiter
Lucy & Trojans: lucy is a spacecraft heading to Jupiter, go through the asteroid belt and then reaches the Trogan
16
Q
asteroid belt: main types
A
S-type: silicate - 15%
C-type: carbonaceous - 75%
M-type: metallic - 10%
17
Q
asteroid belt: former planets
A
4 Vesta & 1 Ceres
Ida
18
Q
asteroid belt: Orisis-Rex
A
- studied the asteroid Bennu, grabbed a piece of the asteroid and brought it back to earth
19
Q
asteroid belt: Widmanstatten pattern
A
- found in space rock, only found if the metal cools very slowly so after 10 million years these crystals form
- unable to be replicated in the lab
20
Q
comets: tails
A
- dust tail: curves as the comet gets ahead of it in its orbit
- gas tail: always points away from the sun
- devlops as it approaches the sun and disappear as it moves away from the sun
21
Q
meteor shower
A
- always cross paths with the earth’s orbit at the same time
22
Q
pluto
A
- discovered in 1930
- New Horizons 2015: not a lot of craters meaning there is a geological process covering the older craters
- mostly ices
- not considered a planet because it crosses Neptune’s orbit and a planet has to have its own distinct orbit
23
Q
orion nebula
A
- protoplanetary disks
- solar nebulas forming around other stars
24
Q
parallax
A
- Friedrich Struve discovered parallax when he measured a parallax of 0.125 arcsec from Vega in 1873
- Friedrich Bessel measured the parallax of 71 Cygni in 1838
- these two measurements are the first distances measurements every made to objects outside our solar system
25
astrometric technique
- barycenter: center of mass
- sun also orbits the center of mass every 12 years
- Juptier actually orbits the center of mass every 12 years but appears to orbit the sun because the center of mass is so close to the sun
26
GAIA
- Global Astrometric Interferometer for Astrophysics
- measuring the Doppler shifts of 1 billion stars
- confirmed astrometric exoplanet discovers: 2
27
GAIA's method
- using the spectral lines of each element
- sun's spectrum
28
radial velocity method
- spectral lines shift back and forth allowing astronomers to see if there is gravitational pull on a star
- P = 4π^2/G(M+m)*a^3 : used to calculate an unseen planet's orbit
Limitations
- better for finding large-mass planets in smaller orbits
- cannot determine the radius of the planet and orbit must be somewhat aligned with earth
29
radial velocity method: successes
51 Pegasi - extremely close to its star, 1/2 mass of Jupiter, hot enough to melt lead
- considered a "hot jupiter": 300 others have been discovered
- found 1036 planets around other stars
30
transit method
- uses the brightness and light curves over time
- confirmed discoveries: 4093
Limitations:
- favors finding large-radius planets in smaller orbits
- orbit must be perfectly aligned to earth to transit cannot be observed
31
TESS
- transiting exoplanet survey satellite
- launched in April 2018
- observing the entire sky
- discovered 333 confirmed planets and 6586 candidates
32
HL Tau
- dust ring around a young star
- reveals multiple rings and gaps that indicate the presence of emerging planets
33
qualifications looking for life: stability and orbit
- must be stable, fairly circular orbit around its star
- must orbit within a "habitable zone": not too hot, not too cold
- highly elliptical orbits result in extreme temperature vibrations
34
qualifications looking for life: time for life to evolve
- massive stars "live" only a few million years
lifetime of a star
- one-solar mass star "lives ten billion years
- 2 solar mass star = 3 billion years
- 16 solarmass star = 10 million years
- but a 0.4 solar mass star could live 200 billion years
- higher mass, shorter lifetime
stellar census
- low mass = high temp
- high mass = high temp
35
qualifications looking for life: liquid water
- habitable zone: region where liquid water could exist (Goldilocks zone)
- Kepler 452b: a little bigger than the earth and orbits its star every 385 days (cousin planet)
- other planets have been found in the habitable zone
36
miller-urey experiment
recreating the conditions for life:
- ball of glass chamber
- sucked all the air out and then replaced it with air of gasses similar to the composition of the early earth: water, methane, ammonia and molecular hydrogen (no oxygen)
- added energy using ultraviolet light or electric sparks and let it cook
- found the building blocks for amino acid proteins
- suggests that life came from the basic gasses with energy
37
the drake equation
Nciv = NHp x flife x fciv x fnow
- NHp: number of habitable planets in the solar system
- flife: how many actually have life (algae, microbes)
- fciv: how many have civilization (technologically advanced ones)
- fnow: lifetime of the civilization
38
drake equation estimates
- 200 billion stars in the milky way
- 5419 confirmed planets
- 361 exoplanets found in habitable zones
39
Trappist-1
- much smaller version of our sun
- a little bit larger than Jupiter
- mass of 9% of our sun
- 40 light years away from the earth
- age estimate: 7 1/2 billion years (3 billion years older than our sun)
- found using a light curve, dims and brightens
- Trappist-1planets: found planets b-h, orbit 1 every day and a half, 4 then 6 and 9
- d and e are in the habitable zone
- extremely close to the star
40
extremophiles
- no ozone layer because there isn't oxygen
- uv from the sun penetrates to the surface
- forms of life under the water and in extreme life conditions like Yellowstone Park or the desert
41
extremophiles: spain's rio tinto
red river with a pH of 2
very acidic
but some microbes thrive in this space
42
extremophiles: H pylori
responsible for stomach ulcers
lives in the acid found in your stomach
43
extremophiles: D radiodurans
survives cold, vacuum and radiation spaces in excess of 1500 times the amount that would kill a human
43
extremophiles: D radiodurans
survives cold, vacuum and radiation spaces in excess of 1500 times the amount that would kill a human
44
extremophiles: tardigrades
half a millimeter in size
found in fresh water
45
black smokers
undersea "black smokers"
volcanic vents erupt from under the crust of the earth and emit black clouds of gasses
