Astronomy Flashcard

Front

What phase of the Moon must it be to have a solar eclipse?

Back

New Moon: A solar eclipse occurs when the Moon is positioned between the Earth and the Sun, which happens during the new moon phase.

Front

What are the two parts of a shadow?

Back

Umbra and Penumbra: The umbra is the darkest part of the shadow where the light source is completely blocked, while the penumbra is the lighter part where the light is partially blocked.

Front

What is retrograde motion in planets?

Back

Retrograde Motion: It refers to the apparent backward movement of a planet in the sky, observed from Earth. In our solar system, two planets exhibit this motion.

Front

Who proposed the heliocentric model before Copernicus?

Back

Aristarchus: An ancient Greek thinker who suggested that the Earth moves around the Sun, challenging the geocentric model.

Front

What does red-shifted mean in astronomy?

Back

Red-shifted: It refers to the phenomenon where light from an object moving away from us shifts toward the red end of the spectrum, indicating that the object is receding.

Front

What is the difference between umbra and penumbra?

Back

Umbra is the fully shaded inner region of a shadow, while penumbra is the partially shaded outer region.

Front

How many planets in our solar system rotate backwards?

Back

Two: Venus and Uranus are the two planets that exhibit retrograde rotation.

Front

What is the significance of the Doppler effect in astronomy?

Back

Doppler Effect: It helps astronomers determine whether an object in space is moving toward or away from us based on the shift in the wavelength of light.

Front

What is the main cause of solar eclipses?

Back

Solar Eclipses: They occur when the Moon passes directly between the Earth and the Sun, blocking the Sun's light.

Front

What is the role of gravity in the orbits of planets?

Back

Gravity: It is the force that keeps planets in orbit around the Sun, balancing the inward pull of gravity with the outward motion of the planets.