Astronomy

What does Newton's 1st Law state?

An object at rest stays at rest, and an object in motion stays in motion unless acted on by a force.

How does gravity relate to planetary motion according to Newton's 1st Law?

Gravity acts as the force keeping planets in orbit, changing their path.

What is the difference between mass and weight?

Mass is the amount of matter in an object; weight is how much gravity pulls on it.

How does surface gravity vary between two planets of the same mass?

The planet with a larger radius has weaker surface gravity because distance from the center is greater.

What is escape velocity?

The speed needed to break free from a planet’s gravity.

What is the electromagnetic spectrum?

The range of all types of light waves, from radio waves to gamma rays.

What properties of light vary across the electromagnetic spectrum?

Wavelength; longer wavelengths have lower energy and shorter wavelengths have higher energy.

What is a blackbody in physics?

An object that absorbs all light and gives off radiation depending on its temperature.

How is color related to wavelength?

Shorter wavelengths (like blue) have higher energy and longer wavelengths (like red) have lower energy.

What is a photon?

A tiny particle of light that carries energy.

What is the Doppler shift?

The change in light or sound waves due to motion.

What shape is Earth and why does it bulge at the equator?

Earth is almost a perfect sphere but bulges slightly at the equator due to its spin.

What layers exist in Earth's crust?

The continental crust (thicker) and the oceanic crust (thinner and denser).

What is the cause of Earth's hot center?

Leftover heat from its formation and radioactive decay inside the core.

What does Earth’s differentiation refer to?

The separation of layers of Earth based on density.

What drives convection currents in Earth's mantle?

The movement of hot, less dense material rising and cool, dense material sinking.

What can be formed at plate boundaries?

Mountains, earthquakes, and volcanoes, depending on how the plates move.

What happens during subduction?

One tectonic plate is forced under another into the mantle, creating volcanoes and trenches.

What is the atmosphere's structure?

It has layers: troposphere, stratosphere, mesosphere, thermosphere, and exosphere.

Why is ozone important in Earth's atmosphere?

It absorbs harmful UV radiation from the sun.

What creates Earth's magnetic field?

The movement of molten iron in the outer core.

Why does the Moon's density differ from Earth's?

The Moon has no iron-rich core like Earth.

How did the Moon likely form?

When a Mars-sized object hit Earth, and debris came together to form it.

What are maria on the Moon?

Flat, dark plains on the Moon.

How do tides on Earth relate to the Moon?

The Moon's gravity pulls on Earth's oceans, causing tides.

What are the main layers of the Moon?

The crust, mantle, and core.

What is the celestial sphere?

An imaginary sphere of stars surrounding Earth.

What do constellations represent?

Groups of stars forming patterns in the sky.

What is the ecliptic?

The path of the Sun which corresponds to a band of constellations, where eclipses occur.

What is the difference between rotation and revolution?

Rotation is spinning around an axis; revolution is orbiting around another body.

What causes the seasons?

The tilt of Earth's axis as it orbits the Sun.

What are the phases of the Moon in order?

New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Third Quarter, Waning Crescent.

Who proposed the geocentric model of the universe?

Aristotle, along with Ptolemy.

Who is known for proposing the heliocentric model?

Aristarchus and Copernicus.

Who developed laws of planetary motion?

Kepler.

What significant observations did Galileo make?

He supported heliocentrism with telescopic observations.

Who formulated the laws of motion and universal gravitation?

Newton.

What is the significance of Tycho Brahe's work?

He made precise observations of planetary motions.

What is Eratosthenes known for?

Calculating Earth's circumference.

What is the definition of planetary motion?

The movement of planets around the Sun due to gravitational forces.

What is the role of inertia in motion?

Inertia is the tendency of an object to resist changes to its state of motion.

What happens to the force of gravity as distance increases?

The force of gravity decreases with increased distance between objects.

What is Kepler's 1st Law of Planetary Motion?

Planets move in elliptical orbits with the Sun at one focus.

What is the difference between a comet and an asteroid?

Comets are icy bodies that develop tails when close to the Sun; asteroids are rocky bodies without tails.

What factors affect the strength of gravity between two bodies?

The masses of the bodies and the distance between their centers.

What is the significance of the axial tilt of a planet?

The axial tilt affects the climate and leads to seasonal changes.

What does a light-year measure?

The distance light travels in one year.

What phenomenon is caused by Earth's rotation?

The day-night cycle.

What happens during a solar eclipse?

The Moon passes between Earth and the Sun, blocking the Sun's light.

What is a supernova?

A powerful explosion of a dying star.

What are exoplanets?

Planets that orbit stars outside our solar system.

How does fusion power the Sun?

Fusion of hydrogen into helium releases energy in the Sun's core.

What type of galaxy is the Milky Way?

A barred spiral galaxy.

What is the significance of cosmic background radiation?

It provides evidence for the Big Bang theory.

What are pulsars?

Highly magnetized rotating neutron stars that emit beams of electromagnetic radiation.