EAPS 106 Exam 3
Why the International Astronomical Union (IAU) did not want Pluto to be a planet.
"If pluto could stay, you logically have to let the number of planets rise to 24 or 25, with the possibility of 50 or 100 within the next decade. Do we want schoolchildren to have to remember so many? no, we want to keep the numbers low." -Gareth Williams, associate director of the IAU's Minor Planet Center.
Basic facts about the Lafayette Meteorite.
- "Discovered" in a drawer at Purdue in 1929; nobody knows how it got there - Identified in 1929 as a meteorite based on its fusion crust - Identified as Martian in the 1980s - From a 1.3 billion-year-old lava flow - 670 million years ago it was exposed to salty water - 11 million years ago it was ejected from the surface of Mars - 2900 years ago it landed on Earth - Determined from radiogenic age dating - Ended up in separate pieces in the Field Museum and the Smithsonian
Good fire safety practices for evacuations and for your home.
- Have an evacuation plan: Escape route, housing, supplied, medicines, and copies of important papers ready to go - Practice how you will communicate with your family - Know how to stay informed - set up text or email alerts, monitor weather reports, buy a weather radio
What is wrong with this depiction of smoke jumpers?
All of the above (smoke jumpers do not free-fall from airplanes, do not land within a fire, and do not jump to rescue people)
Where meteorites are most easily found.
Antarctica, where flowing glaciers collect and deposit them, where they are easily seen on the ice.
The definitions of meteoroids, meteors, and meteorites.
Asteroid is a larger rock in space Meteoroids: Small rocks (less than a few meters across) travelling through space Meteor: Small rocks from space that light up in the night sky as they burn up the earth's atmosphere Meteorites: Small pieces of space rock that survive passage through the atmosphere to be picked up the surface.
Whether the asteroid belt is crowded (can we easily fly through it).
Average distance between asteroids 1 km in diameter is 500,000 km. Average distance between an estimated 10^14 asteroids greater than 1 meter is 5,000 km. So no it is not crowded
The purpose of a fireline and a backburn.
Backburn: controlled burns that eliminate the fuel of incoming wildfires in order to prevent them continuing in that specific direction Fireline: a break in fuel made by cutting, scraping or digging Limits the direction the fire can move Dig into the dirt (so no underbrush fires) and also "limb up" the trees on both sides (cut off the lower, often dead, limbs so there can be no ladder fires) You construct a fireline before performing a blackburn in order to limit the direction of the blackburn
Why fire retardants dropped from air tankers are colored red.
Dyed so that they can see where they've already dropped
Where most impact ejecta lands.
Ejecta (rock thrown out of the crater during impact) mostly lands within one diameter of the crater rim
Why Haley's comet is the most famous of all comets.
Because it is a short-period comet that comes into view about once in a lifetime (~75 years) Only short-period comet visible to the naked eye Last appeared in 1986 will next appear in 2061 Its passage has been recorded since at least 240 B.C.E
Why are the highest percentage of human ignited fires in the southeast?
Because the southeast is hot and densely populated
Why comets are referred to as dirty ice balls.
Because they are mixture of ice and rock
How we can simulate gravity on a spacecraft.
By rotating the spacecraft, generating a centrifugal force that simulates gravity. "Down" always points outwards from the center of rotation
Why the Space Shuttle Challenger and Columbia disasters occurred.
Challenger- An o-ring in the solid rocket boosters gets frozen and doesn't perform as expected due to the cold weather, allowing the pressures it's supposed to contain to escape and cause catastrophic problems. The aft joint failed upon ignition, then took 70 seconds to burn through a strut attaching the booster to the external tank. The detached booster then crushed the external tank releasing oxygen and hydrogen, which mixed and ignited. Columbia- Foam for insulating the external tank broke off and damaged tiles on the orbiter wing, leading to the shuttle disintegrated during reentry and the death of another 7 astronauts.
The fate of all comets.
Comets lose mass with each pass of the sun. After too many passes, the fate is that they break up. When this happens, comet debris continues along the same orbit, forming comet groups, until the pieces eventually fall into the sun.
the best way to search for ancient or current life on Mars.
Examining the surface of Mars with rovers Spectrometers to determine mineral composition and detect organic compounds Radar to image buried layers
What New Horizon's found when it visited Pluto.
Expected to find a dead planet, but found wispy atmosphere, tectonics, different ice types. Sputnik planum is a giant impact Also has a tenuous atmosphere that snows nitrogen flakes.
Why is Mars the most explored planet?
Extraterrestrial life
What was the US Forest Service's original policy regarding fighting wildfires?
Fight them whenever and wherever they occur
The original policy of the U.S. Forest Service toward fighting wildfires
Fight them whenever and wherever they occur, following the disastrous great fire of 1910 their original response to wildfires was to aggressively fight all wildfires.
The three stages of a wildfire.
Fire Triangle: Heat, Oxygen, Fuel. Preignition: Heat of fuels causes them to lose moisture, making them more combustible. Combustion: Hotter temperatures cause fuels to release gases that combine with oxygen in a chemical reaction that releases more heat, leading tot a chain reaction. Smoldering: Ash cover leads to slow, low temperature burning and inhibits new fuels from lighting
The difference between a fire weather watch and warning.
Fire Weather Watch: Potentially dangerous fire weather conditions are possible over the next 12-72 hours. Hot/dry/windy conditions with some thunderstorms. When there are the right conditions to start a fire but there is NOT an actual fire Fire Weather Warning: Wildfires are occurring in the general area or will occur in the next 24 hours.
What is the most common reason why houses in subdivisions catch fire due to wildfires?
Flammable roofs catch on fire from burning embers (firebrands)
The most common reason why houses in subdivisions catch fire due to wildfires.
Flammable roofs catch on fire from burning embers (firebrands) carried by winds Inflammable roofs are expensive
That there are more estimated Earth-like planets than grains of sand on Earth.
For every grain of sand on earth, there are 50 Earth-like planets. Estimated 500 stars for every grain of sand on Earth, 500 times 8x10^18
Where iron meteorites originate from.
From impacts that break up big asteroids that have differentiated into an iron core and a stony mantle
Why do iron meteorites exist?
From impacts that break up big asteroids that have differentiated into an iron core and a stony mantle.
Why Mars is the most explored planet.
It holds the greatest chance of finding evidence of past or present extraterrestrial life
That comet dust jets do not turn on and off with the comet's sunrise and sunset.
Jets are unrelated to sunrise and sunset debris Turn on Sporadically and last short time periods. They can turn on and off in 10s of minutes even though the rotation time is much larger Not sure what initiates them, but could be landslides pushing debris into gas jets
What other planets are disqualified by the IAU's criteria.
Jupiter because it has not cleared the neighborhood of the Trojan asteroids and Neptune because it has not cleared its orbit of pluto
What the definition being proposed by Planetary Scientists to define a planet is based on.
Considers the intrinsic physical properties of planetary bodies, not the nature of their orbits Excludes stars or stellar objects such as white dwarfs, neutron stars, and black holes. As with every other animal, vegetable, or mineral that is defined as dwarf but is still of that species, terrestrial planets, giant planets, dwarf planets, and moon planets, should all simply. "A planet is sub-stellar mass body that has never undergone nuclear fusion and that has sufficient self-gravitation to assume a spheroidal shape regardless of its orbital parameters" - With this "round" definition of a planet, there are at least 110 known planets in our Solar System
The kind of plane first used as an air tanker to fight a wildfire.
Crop duster called a SEAT (single engine air tanker)
Why the Kentland Crater in Indiana does not look like an impact crater
Kentland Crater is about an hour northwest of Purdue, 13 km diameter. Glaciers removed the surface topography 12000 years ago. The newton county quarry is in the craters central peak, where raised, smashed rocks are easy to mine. The kentland quarry is the only place in Indiana where rock layers do no lie horizontal. Shatter cones found throughout the quarry are evidence of the passage of a high pressure shock wave
How we know that the Oort Cloud is a sphere.
Long period comets come form the oort cloud, a spherical collection of billions of small icy objects. We know it's a sphere because long period comets come at us from all directions.
What space junk is.
Man made debris in orbit around Earth. Collisions of satellites, ejection of booster engines. Currently tracking over 750000 pieces of orbiting space junk traveling up to 17500 miles per hour
Where meteor showers originate from.
Meteor showers are created when the earth passes through the remnants of a broken up comet. The Perseid meteor shower comes from a partial breakup of Comet Swift-Tuttle
Where asteroids are found.
Most are found in the main asteroid belt between Jupiter and Mars
What criteria the IAU created to demote Pluto to dwarf planet status.
Must orbit the Sun - Designed to rule out moons Nearly-round in shape - Designed to rule out objects smaller than ~700 km in diameter Clear the neighborhood - Designed to rule out everything in the asteroid and Kuiper belts
The reasons why fires started by lightning tend to burn more acres.
Occurs in more remote areas, goes longer before being noticed, more difficult to fight, often left to burn as a natural process, Human-lit fires have equipment nearby (typically)
Where air tankers usually drop their loads.
On the fuel in front of or next to the fire If the retardant is dropped directly on the fire, it may evaporate from the heat before it reaches the fire
What the Voyager Spacecraft golden records are.
Phonograph record, a 12-inch gold-plated copper disk containing sounds and images selected to portray the diversity of life and culture on Earth. Hoped to be picked up by an alien civilization. Contains data for being read by aliens, 21 cm wavelength and frequency of hydrogen gas sets the scale for other figures. Solar system location relative to pulsars (rapidly rotating neutron stars), spacecraft's origin (3rd planet from the sun). Shows humans relative to the spacecraft. The golden records are phonograph records containing sounds and images from earth. Has directions for playing record
That planet size also matters for a planet to be considered potentially habitable.
Planet size can affect the atmosphere it can hold, too small and can't hold enough, too big and it'll hold things like hydrogen. Needs to be relatively Earth sized .8 - 1.5 Earth's radius
What's wrong with this scene from Red Planet? (probably not going to be on the exam)
Spinning a spacecraft does not actually create a gravity field, so floating objects will not fall
What cause fires to spread faster by directing flames to new fuels.
Strong winds and steep topography can cause fires to spread faster by directing flames to new fuels.
the best strategy to survive an extinction level size asteroid or comet on an intercept course with Earth.
The best collision avoidance strategies involve deflection. Kinetic impact: crash a heavy spacecraft into it to alter trajectory. Spacecraft propulsion: create a small sustained thrust to alter trajectory. Focus solar heat onto a comet surface to create thrust from the resulting vaporization of material and alter trajectory. Solar sail: attach a large solar sail enabling solar pressure to shift the object's trajectory Nuclear weapons: direct hit to vaporize (better not leave big chunks) - detonate a series of devices alongside to alter trajectory
What causes comets to have tails.
The dust and gas molecules are ionized by ultraviolet light from the sun making it emit blue light.
That cryovolcanoes on Saturn's moon Enceladus dumps material from its subsurface ocean into Saturn's E-ring.
The erupted water freezes and feeds Saturn's E-ring. Subsurface ocean revealed by water geysers
Which wildfire was the largest to occur in United States history.
The great fire of 1910 burned 3 million acres in the northwest in two days, killed 87 people, 78 of whom were firefighters, prompting the National Forest Service to start fighting all wildfires, Caused by lightning storms, strong winds.
Why are there more impact cheaters on the moon today than on the earth?
The moon has no erosional processes to erase old impact craters
Why there are more impact craters on the Moon than on the Earth.
The moon has no erosional processes to erase old impact craters.
What influences the potential for a wildfire to spread.
The potential for a wildfire to spread depends on the type of vegetation (some fuels burn more easily), topography (fires burn faster uphill), and weather (hotter and dryer means faster burn).
The general relationship between the size of an asteroid and the size of the crater it produces.
The resulting crater is 15-30 times bigger than the impactor.
Why the highest percentage of human ignited fires occur in the southeastern U.S.
The southeast is hot and densely populated.
Whether all that mass of the asteroid belt would add up to a planet's mass.
The total mass of the asteroid belt adds up to just 4% of the mass of the Moon or .05% the mass of the Earth. Ceres, the largest asteroid, accounts for ⅓ of the mass of all asteroids
Why the surface of many lunar impact basins are black and smooth.
They are large basins filled with lava. The absence of craters within the lava shows it to be much younger than the rest of the lunar surface.
About how fast asteroids hit the Earth.
They generally travel at around 15km/s (32000 mph) this causes asteroids to explode like a bomb on impact. The slowest Earth can be hit is about 11 km/s
What a fusion crust on a meteorite is.
Thin crust that surrounds the meteorite, caused by melting when it passed through the atmosphere
Why ancient hunters set fires to grasslands.
To maintain grasslands, to prevent trees and shrubs from taking over, and to scare prey out from areas for hunting. Grasses can survive fire because they can regrow from the roots while the trees and shrubs cannot
The history and current status of water on the surface of Mars.
Today, the surface of Mars is cold, dry, dusty, and shows no signs of water or life Billions of years ago, there was water in river channels, lake beds, and possibly an ocean basin (can tell from evidence today)
How the Kepler spacecraft detects exoplanets.
Transit method of exoplanet detection- It finds planets crossing their stars by the slight dimming of the star's light.
The outer extent of the orbits of ultra-short-period, short-period, and long-period comets.
Ultra-short-period: <10 years, from within Jupiter Short-period: < 200 years, from the Kuiper Belt (around Pluto) Long-period: > 200 years to orbit, from Oort Cloud
The hazard a spacesuit will and will not protect an astronaut from.
Will protect against micrometeroids: tiny pieces of space rock (millimeters or less) traveling at very high rates of speed (measured in kilometers per second) that can cause a lot of damage. Suits use a layer of kevlar to protect from micrometeoroids. They have several layers of insulation to protect astronauts from the extreme cold (-250F) and extreme heat (250F) of space. Spacesuits have no radiation protection, as that requires much thicker and denser material.
What kind of plane was the first air tanker?
crop duster
What is our best strategy to survive an extinction level size asteroid or mocet on an intercept course with Earth?
deflect it
Which of the following will a spacesuit not protect an astronaut from?
radiation
How far to the closest potentially habitable planet is.
4.2 light years (Proxima Centauri b)
How many stars are out there?
500 times the number of grains of sand on Earth
There are an estimated 1 million asteroids > 1 km in diameter. How far is the average distance between them?
500,000 km
Whether lightning or humans start more wildfires.
85% of all wildfires in the US are caused by humans (the rest by lightning)
What a crater ray is.
A crater ray is a line of ejecta that can extend for 10s of crater diameters.
What killed the Apollo 1 and almost killed the Apollo 13 astronauts.
A fire broke out during a test and spread very rapidly due to using a pure oxygen environment in the capsule, killing 3 astronauts. The liquid oxygen tank on the Apollo 13 stratified and the process of mixing it caused the tank to explode and almost killed the astronauts as well.
What regolith is.
A layer of loose dust and small particles left over from many impacts found on asteroids and other airless bodies
The advantage that a helitankers have over air tankers.
Air tankers - with wheels have to return to some airport to refill their tanks, although seaplanes are able to refill in lakes or reservoirs - Have a higher capacity of water or fire retardant Helitankers - can refill on the go from a pond, lake, pool, etc. - smaller bodies of water than planes - can perform more targeted drops - can also carry water cannons similar to fire trucks - Shorter range to drop - Smaller capacity
Which of the following statements about the IAU's decision to demote Pluto's status is true?
All of the above
About how many Near-Earth Asteroids ≥1 km in diameter are currently being tracked.
1000
The ingredient for s'mores.
2 Graham crackers Chocolate Melted marshmallow
the evidence that a large impact killed off the dinosaurs.
- Iridium, shocked quartz, and soot are found all over the world. Thin layer of these materials separate the Cretaceous period from the Palogene period - All those materials were indicative of giant impact and global fires. The extinction of the dinosaurs was believed to have been caused (at least in part) by a 10 km diameter impact. The cretaceous (dinosaur ruled)-Paleogene (Mammal ruled) (K-P) extinction even occurred 65 million years ago, killing off ~75% of all species on Earth. The thin layer that separates Cretaceous from Paleogene sediments all over the world contains a lot of iridium, shocked quartz, and soot, indicative of a giant impact and global fires. In 1990, the 65 million year old, 180 km diameter Chicxulub crater was identified, buried 1 km under sediments off Mexico's Yucatan Peninsula. Chicxulub was revealed by mapping the gravity signature and dated of cores drilled through the sediments. - Heating of ejecta reentering the atmosphere caused global wildfires. - Dust suspended in the atmosphere blocked sunlight and caused global cooling for many years. - Ejecta disrupted the ozone layer leading to increased UV radiation. - Sulfate-rich marine rocks blasted into the atmosphere transformed into sulfuric acid that rained down on the oceans causing them to become very acidic.
What fire shelters are designed to do and not designed to do.
- Last resort when trapped by wildfires - Designed to reflect heat and trap breathable air against the cool ground - Not designed to protect against direct, sustained contact with flames -- Radiant heat gets reflected, convective heat gets absorbed
The lesson of The Legend of Coyote in terms of wildfires.
- Produced a tale about life coming from death and destruction? - The destruction being fire that renews the earth - The coyote symbolizes wisdom
What surface and crown fires are.
- Surface fires involve grasses, pine needles, and shrubs. The large surface area to volume ratio of these fuels allow them to burn more easily and spread more rapidly. - Crown fires are those in which flames reach the top (crown) of trees where fine branches and needles can burn very rapidly. They are the hottest and fastest moving of all wildfires and extremely difficult to fight.
The factors that contributed to the deaths of the Granite Mountain Hotshot crew.
- They decided to descend from a safe, "in-the-black" area, but as they descended the mountain (from safe spot to safe spot) the fire made an unexpected turn to come up in front of them. They couldn't see the fire coming (because of the steep topography) until it was too late to escape, so they were forced to deploy fire shelters. Because the wind was so strong, the flames were blown directly onto them, and the fire shelters weren't able to protect them. - A sudden downdraft, which changed the direction of the fire -- Due to the incoming thunderstorm - Air tanker didn't see them because of the smoke and miscommunication -- No GPS to relay their exact coordinates - Fire was too hot for their fire shelters to protect them - Nobody knows why they descended from the area of safety
The main function of a smoke jumper.
- To be the elites of the hotshot crews - Firefighter paratroopers jumpers - Jump from a plane and fight the fire in the thick of things - Roads were inaccessible because of the fire, so they traveled by air instead - If a Hotshot crew can't get close enough, fast enough, send in the smoke jumpers
The direction of the gas and dust tails relative to the Sun and the direction of motion of the comet.
Gas tail is pushed directly away from the sun by the solar wind (charged particles streaming from the Sun), composed of molecules ionized by ultraviolet light from the Sun, causing it to emit blue light. Dust tail is swept by pressure from sunlight and falls behind the motion of the comet, separating it from the gas tail. Head of comet faces the Sun
How the Philae lander attempted to land on the surface of Comet Churyumov-Gerasimenko.
Harpoons were deployed to grab onto the surface
The most common cause of death by wildland firefighters.
Heart attacks due to level of exertion involved in being a wildland firefighter
Why fighting smaller fires lead to much bigger ones.
If there are no smaller fires to remove the underbrush and fuel that builds up, they can lead to massive fires due to the built up fuel. In typical forests, every year without fire adds the equivalent of 300 gallons of gasoline per acre.
Why impact craters are almost always round.
Impact craters are almost always round because the impact shock wave travels outward equally in all directions regardless of the impact angle.
How we are protected on this planet from solar flares.
Radiation: The solar wind is a continuous flow of charged particles from the sun. Solar flares are sudden, large energy releases from the sun that carry especially high doses of radiation. Spacecraft are very vulnerable to radiation blasts from solar flares, could overload electrical systems. Earth's magnetic field deflects much of the radiation from the sun and the atmosphere absorbs most of the rest. The absorption in the atmosphere causes the aurora lights
The difference between simple craters, complex craters, and multi-ring basins.
Simple crater - small, bowl shape - Few km impactor Complex crater - medium, central peak, terraced walls - 10s of km impactor Multi-ring basin - large, multiple rings - 100s of km impactor
the mascot used by the U.S. Forest Service to promote fighting all forest fires.
Smokey the Bear. This lead to a generation of massively destructive fires.
What smoke jumpers have at their disposal to fight remote wildfires.
Worn on their bodies: - Chute - Jump Jacket and Pants made of Padded Kevlar - Rope in leg pocket (for accidental tree landing) - High Collar for Tree Landings - Parachute Harness - Reserve Parachute - Personal Gear bag - Wire Mesh face mask - Helmet Also, the plane makes a drop of supplies for actually fighting the fire which includes: Chainsaws, Pulaski axes, shovels for firelines Hoses and pumps to use rivers and other natural sources for water
That there are other objects of similar size to Pluto in the Kuiper Belt.
Yes there is, started to discover other objects in the Kuiper belt in the 1990's with better telescopes. Eris, about the same size as Pluto, is named for the Greek goddess of chaos, strife, and discord, appropriate since it kicked off the debate about the definition of a planet and the demotion of Pluto.
What it means for an exoplanet to exist in the "habitable zone" and what it depends on.
Zone where liquid water can exist on the surface, distance from the sun for the planet. Distance range of the habitable zone depends on the size (temperature) of the star.
In general, how do planetary scientists classify Pluto?
a planet
