Astronomy Final Exam

What is a star?

A large, glowing ball of gas that generates heat and light through nuclear fusion.

What defines a planet?

A moderately large object that orbits a star and shines by reflected light, which may be rocky, icy, or gaseous in composition.

What is an asteroid?

A relatively small and rocky object that orbits a star.

What characterizes a comet?

A relatively small and icy object that orbits a star and has a tail of light caused by the sun.

What causes the tail of a comet?

The sun's heat causes the comet's tail.

How long does it take for a comet to reappear?

It takes about 100 years for a comet to be seen again.

Where do comets originate?

Comets come from the Kuiper belt.

What is a galaxy?

A great island of stars in space, held together by gravity and orbiting a common center.

What role does Earth's axis tilt play in seasons?

Earth's axis is tilted by 23.5 degrees, influencing seasonal changes.

What is the significance of the summer solstice?

It is the longest day of the year.

What is the winter solstice?

The shortest day and longest night of the year.

What is an equinox?

A time when day and night are approximately equal in duration.

What is an emission line spectrum?

A thin or low-density cloud of gas that emits light at specific wavelengths based on its composition and temperature, producing bright lines in a spectrum.

What is the ozone layer?

A thin protective layer of oxygen in the atmosphere.

How does light behave?

Light is a wave that travels at the speed of light.

What types of light are produced by the sun?

Gamma rays, X-rays, ultraviolet light, visible light, infrared, microwaves, and radio waves.

What does the greenhouse effect do?

It traps IR light in the atmosphere, warming the Earth.

What is the purpose of adaptive optics in telescopes?

To change the shape of a telescope to compensate for atmospheric distortion.

Who was Galileo Galilei?

The first scientist to discover the moons of Jupiter and to use a telescope to study the sky.

What is Kepler's First Law?

The orbit of each planet around the Sun is an ellipse with the sun at one focus.

What does the Doppler Effect measure?

Shifts in the wavelengths of spectral lines to determine movement.

What is tidal locking?

When the moon rotates at the same speed as it orbits the Earth, causing one side to always face the planet.

Why is Mars considered to have had a warmer and wetter past?

Evidence from ancient water channels and drainage suggests it once had rivers, lakes, and possibly oceans.

What are the two types of nuclear energy?

Fusion and fission, which involve changing atoms to release energy.

What is the significance of E=MC2?

It shows that all mass has a significant amount of energy stored within it.

What is the primary composition of the Earth's atmosphere?

79.1% Nitrogen, 20.9% Oxygen, and small percentages of Argon and Carbon Dioxide.

What causes Earth's seasons?

The tilt of the Earth's axis and its orbit around the sun causes seasonal changes.

What are the main properties of terrestrial planets?

They are low mass, have high density, are slow rotators, and have few satellites.

What is the significance of a telescope's diameter?

A larger diameter increases the resolution of the images captured.

What is the structure of the Earth's interior?

Includes a solid iron core surrounded by a liquid iron outer core.

What is the greenhouse effect's relationship with CO2?

CO2 is a greenhouse gas that helps regulate Earth's temperature.

How can we measure the mass of a star?

By observing the gravitational influence on other objects, such as planets.

What is the Roche zone?

A region around a planet where tidal forces prevent the formation of moons from particles.

What is the Giant Impact theory regarding the Moon's formation?

It posits that a Mars-sized object collided with the early Earth, ejecting material that formed the Moon.

What is the main characteristic of Jupiter?

It has a large rocky core with gaseous hydrogen and helium surrounding it.

What are comets composed of?

Comets are composed primarily of ice and dust, forming tails when near the sun.

How do heavy and light gases behave in a planet's atmosphere?

Heavier gases remain closer to the surface, while lighter gases can escape more easily.

What is the Albedo effect?

The reflectivity of planetary surfaces, impacting the temperature and climate.

What is the process of planetary formation?

Dust and gas from former stars contract, leading to the growth of planets.

What caused the warming of Venus?

A runaway greenhouse effect caused by high levels of CO2.

What is an example of a planet detection method?

The transit method, which looks for the shadow of a planet crossing a star.

What is the role of gravity in shaping planetary surfaces?

Gravity pulls matter together, influencing impacts, volcanism, erosion, and tectonics.

Why are Mercury and Venus considered terrestrial planets?

They have solid surfaces, are rocky, and are comparatively small.

What makes Io unique among moons?

Io is known for its intense volcanic activity, making it very geologically active.

What distinguishes Europa from other moons?

Europa has an icy crust covering a subsurface ocean, suggesting potential for life.

Why is Titan significant?

It is the largest moon of Saturn and has a dense atmosphere rich in hydrocarbons.

What is interstellar reddening?

The phenomenon where stars viewed through dust clouds appear redder due to shorter wavelength light being blocked.

How do stars evolve?

Stars change over time due to internal processes such as nuclear fusion.

What is the importance of studying moons and rings?

They provide insights into the history of planetary formation and dynamics.

What is the density of water?

1 gram per cubic centimeter.

What is visible light?

Light that can be seen by the naked eye, part of the electromagnetic spectrum.

What defines a dwarf planet?

A celestial body orbiting the sun that is not a satellite and has not cleared its orbit.

What is the primary function of a radio telescope?

To detect radio waves from astronomical objects.

What does solar wind interact with on Earth?

The Earth's magnetic field, leading to phenomena like the Northern Lights.

What is Earth's magnetic field?

A magnetic field generated by movements in the Earth's liquid outer core.

What is thermal radiation?

Radiation emitted by objects based on their temperature.

What are the phases of matter?

Solid, liquid, and gas, each characterized by different properties.

What role did volcanic activity play in Earth's early atmosphere?

Volcanism released gases that contributed to the formation of a stable atmosphere.

Why does Mars have a thin atmosphere?

Due to its low gravity and lack of a magnetic field, it cannot hold onto gases effectively.

What is the significance of sedimentary rock on Mars?

It may contain evidence of past water flow and possible life.

What is the primary greenhouse gas that regulates Earth's temperature?

Carbon dioxide (CO2).

What is the difference between regular and irregular moons?

Regular moons have circular orbits in the equatorial plane, while irregular moons have highly elliptical orbits.

What evidence supports Mars having had liquid water?

Ancient drainage channels and signs of past water flow on the surface.

What defines a binary star system?

A system where two stars orbit around a common center.

What are some of the key factors affecting a planet's atmosphere?

Gravity, temperature, and the presence of volcanic activity.

What historical event is associated with a comet impact?

The extinction of the dinosaurs, caused by a comet or asteroid impact.

What influences the brightness of a star?

Both its distance from Earth and its luminosity.

What were the main discoveries of Clyde Tombaugh?

Clyde Tombaugh discovered Pluto and contributed to our understanding of the outer solar system.

What is unique about Pluto's orbit?

Pluto's orbit is highly elliptical and tilted compared to the orbits of the other planets.

What are the main components of a star's internal structure?

Core, radiation zone, and convection zone.

What is the astronomical significance of Jupiter's Great Red Spot?

It is a gigantic storm that has persisted for at least 350 years.

What implications does studying the phosphine on Venus have?

It raises questions about potential microbial life in Venus's atmosphere.

What are tides and how are they caused?

Tides are caused by the gravitational pull of the moon and the sun on Earth's waters.

What does the term 'luminosity' refer to?

The actual brightness of a star, independent of its distance from Earth.

What is a black hole?

A region of space where gravity is so strong that nothing can escape from it.

What is the primary method used to study the surface of Venus?

Radar mapping through atmospheric clouds.

How do we define a planet's habitability?

By assessing its potential to support life, considering aspects like water availability.

What is the primary distinction between giant planets and terrestrial planets?

Giant planets are massive, gas-rich, and lack solid surfaces, while terrestrial planets are rocky and smaller.

What is the significance of the Van Allen radiation belts?

They trap charged particles in Earth’s magnetosphere, protecting the planet from solar and cosmic radiation.

What mechanisms do scientists use to detect exoplanets?

Methods include the transit method and the Doppler effect.

What makes Jupiter's moon Europa a candidate for containing life?

Its subsurface ocean beneath an icy crust may harbor conditions suitable for life.

What do the terms 'absolute magnitude' and 'apparent magnitude' refer to?

Absolute magnitude is the intrinsic brightness of a star, while apparent magnitude is its brightness observed from Earth.

What role does the sun play in the formation of the solar system?

The sun's gravity helped to form planets and other bodies through the solar nebula theory.

How is Earth's carbon cycle currently disrupted?

Through human activities that increase CO2 levels, influencing climate change.

What are the major features of Saturn's rings?

They are composed of millions of ice particles, ranging in size from tiny grains to large chunks.

What differentiates the Kuiper Belt from the Oort Cloud?

The Kuiper Belt is a region of the solar system beyond Neptune, while the Oort Cloud is a hypothetical shell of icy objects much farther out.

What unique characteristics does Titan have compared to other moons in the solar system?

Titan has a thick atmosphere and stable surface liquids, likely including lakes of methane and ethane.