space unit two

Why does Mercury have so many old craters compared to Earth?

Mercury has no atmosphere to burn up space debris and very little geological activity to erase or reshape its surface.

Which planet is actually hit by space debris more often: Earth or Mercury?

Earth. It is hit about 10 times more frequently than Mercury, but its active geology continuously erases the craters.

What are the four major geological processes that shape planets and moons?

Impact Cratering (collisions from space), Volcanism (volcanoes/lava), Tectonism (crust movement), and Gradation (erosion/deposition).

What are lunar "Maria" and how did they form?

Dark, flat plains formed when ancient impact basins filled with dark basaltic lava.

Why can Lunar Highlands reach greater heights than mountains on Earth?

The Moon has less gravity and no atmosphere to erode them down.

What are "Rilles" on the Moon?

Long, trench-like valleys found on the lunar maria.

What are "Rays" on the Moon?

Long trails of debris radiating outward from impact craters.

What is the largest crater on the Moon, and how wide is it?

The Aitken Basin, measuring 2,100 km across.

What is "Regolith"?

Lunar "soil" made of a mixture of grey-brown rock fragments and fine dust.

What did Nicolaus Copernicus correctly propose, and what mistake did he make?

He correctly proposed the heliocentric model (Sun-centered), but incorrectly assumed planetary orbits were perfect circles.

What was Tycho Brahe's major contribution to astronomy?

He collected exceptionally precise quantitative measurements of planetary motion (especially Mars).

How did Johannes Kepler solve the mystery of planetary orbits?

He used Tycho Brahe's data to discover that planetary orbits are elliptical, not circular.

What is Kepler's First Law of Planetary Motion?

The Law of Ellipses: Planetary orbits are ellipses with the Sun at one focus.

What is Kepler's Second Law of Planetary Motion?

The Law of Equal Areas: A line connecting a planet to the Sun sweeps out equal areas in equal time (planets move faster closer to the Sun).

What is Kepler's Third Law of Planetary Motion?

The Harmonic Law: The square of a planet's orbital period (T^2) is directly proportional to the cube of its average distance from the Sun (r^3).

Define Perihelion vs. Aphelion.

Perihelion: Closest point to the Sun (moves fastest). Aphelion: Farthest point from the Sun (moves slowest).

Define Perigee vs. Apogee.

Perigee: Closest point of a moon to its parent planet. Apogee: Farthest point of a moon from its parent planet.

What giant planet acts as a gravitational shield to protect Earth from cosmic threats?

Jupiter.

What causes ocean tides on Earth?

The gravitational pull of the Moon and the Sun.

What is a Spring Tide and when does it happen?

A higher-than-normal tide that happens when the Sun and Moon line up (on opposite or the same sides of Earth) and pull together.

What is a Neap Tide and when does it happen?

A lower-than-normal tide that happens when the Sun and Moon are at a 90-degree angle, counteracting each other.

Where are the largest tides in the world located?

The Bay of Fundy in Canada.

What is the difference between a lunar eclipse and a solar eclipse?

Lunar Eclipse: Earth's shadow falls on the Moon. Solar Eclipse: The Moon blocks the Sun, casting its shadow on Earth.

What is Solar Wind and what everyday infrastructure can it disrupt?

A stream of charged particles from the Sun's corona that can cause magnetic storms, disrupting satellites, cell service, and power grids.

Name three benefits and one hazard of solar radiation.

Benefits: Warms the planet, drives food chains, aids Vitamin D synthesis. Hazard: Excess UV radiation causes skin cancer.

What are the three primary ethical/practical debates surrounding space exploration?

Speed & Safety (high human risk), Cost vs. Value (massive financial cost), and Environmental Impact (space debris/junk).

What was the first artificial satellite, who launched it, and when?

Sputnik 1, launched by the USSR on October 4, 1957.

Which two tragic space missions resulted in the loss of 14 total crew members during launch/re-entry?

Challenger (exploded 73 seconds after liftoff in 1986) and Columbia (broke apart during re-entry in 2003).

Who were the first two humans to walk on the Moon, and when?

Neil Armstrong and Buzz Aldrin on July 21, 1969 (Apollo 11).

What was the purpose of having the space shuttle Endeavour on standby during the 2008 Hubble mission?

To serve as an immediate rescue vehicle if the primary shuttle was damaged by orbital space debris.

Who built the first liquid-fueled rocket?

Robert Goddard.

Which German rocket scientist developed the V-2 rocket in Nazi Germany and later helped the US space program?

Wernher von Braun.