Astr 121 JMU Sean Scully Exam Review 1

What is scientific notation and provide an example?

Scientific notation is a way to express very large or very small numbers using powers of ten. For example, 1,232,000,000 can be expressed as 1.232×10^9.

What is an astronomical unit (A.U.)?

An astronomical unit (A.U.) is the average distance from the Earth to the Sun, approximately 93 million miles or 150 million kilometers.

What are the steps of the scientific method?

The steps of the scientific method typically include observation, hypothesis formation, experimentation, analysis, and conclusion.

What is the difference between a theory and a hypothesis?

A hypothesis is a proposed explanation that can be tested, whereas a theory is a well-substantiated explanation based on a body of evidence.

What is a Fermi problem?

A Fermi problem is a question that requires estimation and calculation based on known facts to arrive at a rough answer.

Define constellation.

A constellation is a group of stars that form a recognizable pattern in the night sky.

What is the celestial sphere?

The celestial sphere is an imaginary sphere surrounding the Earth onto which all celestial bodies can be projected.

What are Kepler's three laws of motion?

Kepler's three laws state: 1) Planets move in elliptical orbits with the Sun at one focus, 2) A line from the planet to the Sun sweeps out equal areas in equal times, and 3) The square of the period of a planet's orbit is proportional to the cube of the semi-major axis of its orbit.

What does Kepler's third law look like in A.U. and years?

Kepler's third law states that the square of the period of a planet's orbit (in years) is equal to the cube of the semi-major axis of its orbit (in A.U.: P² = a³).

What is Newton's universal law of gravitation?

Newton's universal law of gravitation states that every mass attracts every other mass in the universe, and the force of attraction is proportional to the product of their masses and inversely proportional to the square of the distance between their centers.

What is the difference between weight and mass?

Mass is the amount of matter in an object measured in kilograms, while weight is the force exerted by gravity on that mass, measured in newtons.

Explain how Roemer measured the speed of light.

Roemer measured the speed of light by observing the timing of Io's orbital periods around Jupiter and noticing variations based on Earth's distance from Jupiter.

What is a spectrum?

A spectrum is the range of different colors produced when light is dispersed by a prism or diffraction grating.

What is Wein's law?

Wein's law states that the wavelength of the peak emission of a black body is inversely proportional to its temperature.

What is ionization?

Ionization is the process of an atom or molecule gaining or losing electrons, resulting in a charged particle. It can exhibit specific emission or absorption lines.

How can we identify chemical elements in a spectrum?

We can identify chemical elements in a spectrum by analyzing the specific wavelengths of light absorbed or emitted by the elements present.

What is the Doppler effect?

The Doppler effect is the change in frequency or wavelength of a wave in relation to an observer moving relative to the wave source.

What are the three properties of a telescope?

The three properties of a telescope are light-gathering ability, resolving power, and magnification. Light-gathering ability is the most important.

What are the advantages of CCD cameras over photographic plates?

CCD cameras have higher sensitivity, can capture images with less light, have a wider dynamic range, and can be easily processed.

What is the current state of the art telescope in the U.S.?

The current state of the art telescope in the U.S. is the James Webb Space Telescope (JWST), which is designed to observe deep space and determine the mass of black holes.

What is the sunspot cycle?

The sunspot cycle is the approximately 11-year cycle in which the number of sunspots and solar activity increases and decreases.