Space Exploration Unit E

Practice flashcards covering Space Exploration Unit E, including historical views of the cosmos, planetary motion models, star lifecycles, solar system objects, and space travel technology.

What is the appearance of the Pillars of Creation in the James Webb Space Telescope's near-infrared view?

The pillars appear as arches and spires rising out of a desert landscape, filled with semi-transparent gas and dust where young stars are forming.

How old is the bone that scientists believe depicts the phases of the moon?

$30000$ years old.

What is the oldest site with definitive astronomical connections, and when does it date from?

Newgrange passage Tomb in Ireland, dating from about $3200\,B.C.$

What occurs at the Newgrange passage Tomb for about two weeks surrounding the winter solstice?

Light passes through a roof box above the entrance passage, causing the entire central passageway to be illuminated.

What is the literal meaning of the word 'solstice'?

Sol (sun) stice (stops).

On which dates do the summer and winter solstices typically occur?

Summer solstice is on June 21 and winter solstice is on December 21.

What astronomical events were the stones at Stonehenge possibly aligned to predict?

Solar and lunar eclipses.

What is the literal meaning of 'equinox' and when do they occur?

Equi (equal) nox (night); occurring on March 21 (spring) and September 22 (fall).

What is the significance of the $28$ spokes in the Medicine Wheel in Wyoming?

They represent the number of days in the lunar cycle.

Which ancient civilization saw the sky as the arched body of the goddess Nut?

The Egyptians.

In the geocentric model proposed by Aristotle, what was at the center of the universe?

The Earth.

When did Nicolaus Copernicus propose the heliocentric model and what did it suggest?

In $1530$; it suggested the Sun was at the center of the universe.

Which scientist invented the first telescope in the $1600s$ and used it to confirm the heliocentric model?

Galileo Galilei.

What did Johannes Kepler discover about the shape of planetary orbits?

They are ellipses and not circles.

What is the definition of an astronomical unit ($AU$)?

The average distance from the center of the Earth to the center of the Sun, which is $149\,599\,000\,km$.

How far is a light-year in kilometers?

$9.5\,trillion\,km$ (based on light traveling at $300\,000\,km/s$).

How long does it take for light from the Sun to reach Earth?

About $8\,min$.

What is a star primarily made of?

Hydrogen.

What does the color of a star indicate about its surface?

Its temperature; very hot stars look blue and cooler stars look red.

At what temperature does hydrogen start to change to helium through nuclear fusion in a protostar?

$10\,000\,000\,^\circ C$.

What is the massive shock wave created when a massive star runs out of fuel and collapses rapidly?

A supernova.

What is a black hole?

A highly dense remnant of a star with gravity so strong that not even light can escape.

How many constellations are officially recognized by the Astronomical Union?

$88$.

What are unofficial constellations, such as the Big Dipper, called?

Asterisms.

Which model is used to explain the birth of solar systems?

The Protoplanet hypothesis (also called nebular theory).

What are the four inner, or terrestrial, planets?

Mercury, Venus, Earth, and Mars.

Which planet is known as the hottest in our solar system with a temperature of $480\,^\circ C$?

Venus.

Where does the asteroid belt lie within our solar system?

Between Mars and Jupiter.

How often is Halley's comet visible from Earth?

Every $76\,years$.

What is the difference between a meteor and a meteorite?

A meteor is the streak of light caused by a meteoroid heating up in the atmosphere; a meteorite is the fragment that actually reaches the ground.

What is the coordinate for the highest point directly overhead in the sky?

The Zenith ($90^\circ$ altitude).

What percentage of a rocket's mass is typically comprised of fuel?

$91\%$.

What gas is used as propellant in an Ion Drive?

Xenon gas.

What was Canada's first satellite, launched in $1962$?

Alouette I.

How does microgravity affect the bone density of astronauts?

Astronauts can lose up to $1.5\%$ of their bone mass each month.

What process is used on the International Space Station to produce oxygen from recycled water?

Electrolysis.

What is a geosynchronous orbit?

An orbit where a satellite rotates in-sync with the Earth, enabling it to stay in one position above the ground.

How many GPS satellites are in orbit to ensure at least three are above any location at any time?

$24$.