Lecture #10 -Meteorite Impacts Flashcards

1
Q

How was the solar system formed?

A

Cloud of Gas and dust in space was disturbed by a supernova

4.6 billion years ago

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2
Q

What is Nebular Hypothesis?

A

The explosion made was in space. This caused the formation of a solar nebula ( a flattened cloud of gas and dust)

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3
Q

What is a super nova?

A

Explosion of a star

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4
Q

How were the planets formed?

A

caused from the centre of the solar nebula grew hotter resulting int he formation of the sun
-the edges cooled causing clumps of particles that stick together and form planets

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5
Q

Whats a galaxy?

A

A cluster of billions of stats

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6
Q

Whats a star?

A

A hot glowing ball of gas that generates energy by converting H–>He

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7
Q

How long does it take to travel from one side to the other of the galaxy?

A

~100,000 lightyears

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8
Q

What is the temp in the middle of the sun?

A

15 million Degrees C

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9
Q

What is the photosphere?

A

Outermost part of the sun

-6000 degrees C

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10
Q

What controls the earths climate system

A

energy from the sun

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11
Q

What is the order of the 8 planets?

A

Mercury-Venus-Earth-Mars-Saturn-Jupiter-Uranus-Neptune

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12
Q

Why is Pluto not a planet?

A

Because there are a lot of other bolides that circle the solar system, that are the same size of Pluto and we don’t consider them planets so we took them out

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13
Q

What happens at the end of a stars lifecycle?

A

They grow bigger until they explode and massive amounts of energy is released

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14
Q

What is a bolide?

A

Extraterrestrial bodies that originate in outerspace

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15
Q

What is an Asteroid

A

A rocky metallic material in space 10-100m in diameter originating in the asteroid belt

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16
Q

What is a Meteoroid?

A

Smaller objects in space up to 10m in diameter

17
Q

What is a Meteor?

A

A meteoroid that has entered earths atmosphere

18
Q

What is a Meteorite?

A

A meteor that strikes the earth surface

19
Q

What is a comet?

A

These are distinguishable by a glowing tail of gas and dust

20
Q

What are comets made from?

A

gas and ice and has a rocky core

-they create the light as gases are released

21
Q

What is an air burst?

A

Bolide that travel at velocities of 12-72km/s. They enter the atmosphere and explode at an altitude between 12-50 km above the surface

22
Q

The Tunguska Airburst

A

Destroyed a lot of forest in 1908
-no crater was found so it was deemed and air burst
-asteroid was probably ~25-50m
0shockwave produced the airburst

23
Q

The Chelyabinsk Airburst

A

Feb 15 2013
Meteor exploded over a city in Russia
1500 people injured due to broken glass

24
Q

What is an ejecta blanket?

A

Layers of debris consists of rock fragments that were blow out of the crater on impact

25
Q

Why arent todays craters as deep?

A

Because of erosion and weathering over time

26
Q

Barringer Crater?

A

50 000 years old located in Arizona
Hole filled in over time due to wind and erosion
Shockwaves blew out the material

27
Q

What are simple craters?

A

Less than a few km

Doe not have an uplifted centre

28
Q

What is a complex crater?

A

Rim collapses under extreme faulting
Centre flood that rises following impact
greater than 6km

29
Q

Chesapeak Crater?

A

discovered by surface imaging
Formed 35.5 million years ago
didnt overlain with ocean and sediments

30
Q

Why are craters more common on the moon?

A
  • Most impacts occur in the ocean so no crater is produced
  • most have eroded away
  • smaller bolides burn up in the atmosphere
31
Q

Shoemaker Level comet

A

Entered Jupiters atmosphere in 1994
released massive amounts of energy
-this could happen to us one day too
destroying everything

32
Q

What is the K-T boundary Mass extinction?

A
  • 65 million years ago, an asteroid impacted the earth, ending the dinosaurs
  • Found large amounts of Iridium (uncommon on earth but common in space)
  • Crater discovered in 1991 in yucatan Peninsula Mexico under sediment and ocean
  • asteroid was prob ~10km
33
Q

Where to asteroids have to stay in order for them not to pose a risk to us?

A

Mars and Jupiter Asteroid belts

34
Q

how do we disturb an asteroids path?

A

Blowing it up or hitting it with another asteroid

-nuclear explosions