Unit 5: Possible Alien Life, Asteroids and Comets

Question 1

Fermi’s Paradox (3 Points)

Answer 1

If extraterrestrials are so common…

1. why haven’t they visited?
2. Why haven’t they communicated with us?
3. why haven’t they left behind some residue of their existence, such as heat or light or some other electromagnetic offal?

Question 2

Trying to calculate the probability that extraterrestrial life exists in the universe is quite ____.

Answer 2

Complicated

Question 3

What did Frank Drake create? Was it useful?

Answer 3

He created a mathematical equation to account for the conditions required to enable such civilization to develop. None of his variables, except one (rate of star formation) could be formulated with confidence.

Question 4

SETI

Answer 4

Search for Extra-Territrial Intelligncce –> it is the search for existence through radio waves.

Question 5

Modern issues with SETI

Answer 5

That people are shifting away from telecommunications from radio and into buried fiber optics.

Question 6

If we find a planet that is capable of life 400 light years away, what is the problems…

Answer 6

we are seeing that planet 400 years in the past, by the time we send a message to them, life could have been extinct on that planet.

Question 7

Infinity was invented to account for…

Answer 7

the possibility that in a never-­‐ending universe, anything can happen.

Question 8

According to Prof Watson there is a limit to..

Answer 8

evolution is the habitability of Earth, and any other Earth-­‐ like planets, which will end as the sun brightens.

Question 9

Prof Watson suggests the number of evolutionary steps needed to create intelligent life in case of humans is four. These include:

Answer 9

1. Emergence of Single-Celled Bacteria
2. Complex Cells
3. Specialized cells allowing complex life forms
4. Intelligent life with an established language

Question 10

Why is intelligent life so much less common according to Prof Watson

Answer 10

Complex life is separated from the simplest life forms by several very unlikely steps

Question 11

Seven Reasons why scientists believe that life is out there..

Answer 11

1. Extremophiles on Earth - organisms that can survive extreme heat, cold and even in vacuum
2. Evidence of chemical precursors to life on other planets –> the original chemical reactions that brought about life is proven on other planets.
3. Rapidly expanding # of Earthlike planets–> due to new techniques and better tech.
4. Sheer diversity and tenacity of life on Earth –> there are many different climates and natural disasters that life managed to survive through (ex. the Ice Age)
5. Mystery surrounding origin of earth –> there is still mystery on how the chemical reactions occurred to form life.
6. Growing evidence that oceans and lakes are common –> that are signs of water in our solar system –> mars and saturns moon titan
7. Evolutionary theory –> suggests that life adapts to its environment thus can adapt to outer space.

Question 12

Tardigrades

Answer 12

are tiny creatures that can survive in the vacuum of space.

Question 13

Panspermia

Answer 13

a theory which suggests that life on Earth arose due to life on other planets

Question 14

Why is mars likely for life formation

Answer 14

had water and is in habitable zone

Question 15

Does life need water to come about?

Answer 15

No, earth has carbon-based life so there is a possibility for other life forms to exist.

Question 16

Why do we look for water for other planets?

Answer 16

It acts like a universal solvent.

Question 17

How can you tell when a distant planet transits its host star when you can’t see the star?

Answer 17

You analyze the wavelengths of the beam of light from that star and when you see a dip, it determines an object has crossed it.

Question 18

How can they tell how long it would take a planet from another solar system to orbit its host star?

Answer 18

When you look at it → it goes from redshift to blueshift back to redshift → one orbit

Question 19

What materials are in the Kuiper Belt

Answer 19

frozen volatiles(gases) such as methane, ammonia, nitrogen and water.

Question 20

Difference between short-period and long comets?

Answer 20

Short Period: Kuiper and orbit sun every less than 200 years.

Long Period: Oort Cloud and orbit sun every more than 200 years.

Question 21

___ is the farthest object in the solar system ever to be resolved by a telescope.

Answer 21

Quaoar

Question 22

Shape of Kuiper belt

Answer 22

disk shaped.

Question 23

KBO…

Answer 23

Kuiper Belt Object

Question 24

How do we spot far off worlds if we can’t see?

Answer 24

Star’s wobble → you can see it redshifting/blueshifting

Question 25

Oort Cloud shape and why?

Answer 25

- Outer cloud is spherical, inner cloud is disk shaped | - spherical because objects got too close to planets thus were blasted outward in all directions.

Question 26

Oort cloud's cloud of particles is theorized to be...

Answer 26

the remains of material that formed the Sun and planets.

Question 27

Hale-Bopp

Answer 27

comet that swung near Earth in 1997 and was visible to the naked eye for 18 months. just stood there

Question 28

Asteroids and comets are considered...

Answer 28

remnants from the giant cloud of gas dust

Question 29

Diff between Asteroids and comets? (4)

Answer 29

``` Asteroids: Rocky Formed close to the sun no tail Shorter, more circular orbits ``` ``` Comest: Icy Formed further from the sun Tails Elliptical (egg-shaped) orbits ```

Question 30

Why do comets have tails while asteroids do not?

Answer 30

Because since comets have icey shells, the ice vapourizes when it comes near the sun.

Question 31

Why do comets have icy shells while asteroids do not?

Answer 31

because asteroids form closer to the sun where it is too warm for ice to remain solid.

Question 32

What is the largest known TNO (Trans Neptunian Object)?

Answer 32

Pluto

Question 33

The largest asteroid is...

Answer 33

Ceres

Question 34

Binary Asteroid

Answer 34

two rocky bodies of equal size orbit each other

Question 35

Three types of Asteroids...

Answer 35

1. C Type (Carbonaceous): Made of carbonates and are dark. Furthest from sun 2. S-Type (Silicaeous): made of silicate (stony) material closest to sun 3. M-Type (Metallic): made of nickel-iron in between

Question 36

NEO stands for

Answer 36

Near Earth Object

Question 37

Why do meteors burn up in the atmosphere?

Answer 37

They move so fast, that friction between rock and atmosphere is great.

Question 38

Why is it easier to land on an asteroid than a comet?

Answer 38

Asteroids are closer

Question 39

How does a comet form a tail

Answer 39

When it warms up near the sun, it develops an atmosphere or coma, surface changes to gas as coma gets bigger, forming a tail

Question 40

Two tails of a comet

Answer 40

the dust tail and the plasma tail

Question 41

Meteoroid

Answer 41

small pieces of space debris that are on collision course with earth. smaller than asteroids

Question 42

Meteors

Answer 42

meteoroid that burns up in the atmosphere. Another name is a shooting star

Question 43

Meteorite

Answer 43

Meteoroids that survive the atmosphere and crash into earth

Question 44

Bolide

Answer 44

when the meteor burns up

Question 45

Meteor Shower

Answer 45

a celestial event in which a number of meteors are observed to radiate from one point in the night sky

Question 46

Only ____ meteoroids make craters

Answer 46

only large

Question 47

Chicxulub Crater

Answer 47

destroyed the dinosaurs 65 million years ago

Question 48

Would blowing up an meteoroid prevent damage on Earth?

Answer 48

No because (1) It would amagaliate (get together) within hours, (2) More damage through more debris

Question 49

How would you prevent an asteroid from hitting earth?

Answer 49

Shot a missile to shift it off course (not exploding it)

Question 50

______ are a result of Jupiter's gravitational field.

Answer 50

short-period comets

Question 51

The nucleus of a comet is about ______in radius.

Answer 51

16 km

Question 52

The Barringer meteor crater is a mile wide. The asteroid

Answer 52

10 yards

Question 53

What effect of a meteor impact may have killed the dinosaurs?

Answer 53

the dust blocking sunlight

Question 54

Ceres, the largest asteroid, has a diameter of about

Answer 54

1000km

Question 55

Which of the following killed over 15,000 reindeer, and produced a shock measured around the world?

Answer 55

Tunguska event

Question 56

Ceres is BEST classified as a(n)__________________.

Answer 56

dwarf planet

Question 57

Meteor showers (like the Perseids in August) occur annually when...

Answer 57

when Earth crosses the orbit of a comet.

Question 58

If all the asteroids in the asteroid belt were assembled into a planet, it would have a mass ____ than the earth

Answer 58

much less than

Question 59

The orbits of comets can... (2)

Answer 59

1. Extend far out beyond Pluto's orbit. | 2. Oriented in any direction

Question 60

When does a comet have the longest tail and largest coma?

Answer 60

when it is nearest the sun *Think about when comet’s are the hottest.*

Question 61

Approximately how large must a meteoroid be in order to survive passage through the atmosphere and reach the ground as a meteorite?

Answer 61

as big as a house

Question 62

The particles which produce meteor showers come from

Answer 62

dead comets

Question 63

What is the source of the material that causes meteor showers?

Answer 63

The nuclei of comets gradually disintegrate and spread out along the comet's orbital path.

Question 64

What material is found in asteroids?

Answer 64

hydrocarbons

Question 65

Why are many of the newly detected extrasolar planets called "hot Jupiters"?

Answer 65

Their masses are similar to Jupiter but they are very close to the central star and therefore hot.

Question 66

Why is it highly likely that if life exists elsewhere in the universe that it will be based on carbon chemistry?

Answer 66

Carbon is versatile in forming complex, long-chain molecules.

Question 67

Life on earth is carbon-based. Similar molecules could be formed with

Answer 67

silicon

Question 68

What organisms alive today is likely to be most similar to the first life forms that evolved on the earth

Answer 68

methane-producing bacteria

Question 69

Single-celled organism that thrive in extreme conditions are primarily

Answer 69

bacteria

Question 70

What is a major stumbling block for scientific theories about the origin of life on early Earth?

Answer 70

How life could arise in the hostile environment of the early Earth.