test 2 astronomy 4,5,6

Speed

rate at which an object is moving

Velocity

speed in a certain direction

Acceleration

change in velocity (change in either speed or direction)

Units of acceleration

m/s^2

Acceleration of gravity

acceleration of a falling object

Freefall

an object is in freefall when there is nothing that prevents an object from falling.

Newton's first law

an object maintains a constant velocity if there is no net force acting upon it.

Newton's second law

force equals mass times acceleration.

Newton's third law

for any force there is always an equal and opposite reaction force.

Kinetic energy

energy of motion.

Radiative energy

energy carried by light.

Potential energy

stored energy.

Law of universal gravitation

every mass attracts every other mass.

Bound orbit

an object that goes around another object over and over again.

Unbound orbit

an object that brings another object close just once.

Orbital shapes

possible shapes include unbound hyperbolic orbit, unbound parabolic orbit, and bound elliptical orbit.

Escape velocity

the speed needed to break free from a gravitational field.

Tidal force

the stretching force created by the gravitational interaction between the Earth and the Moon.

Inverse square law

gravity follows the inverse square law.

Mass

the amount of matter in an object.

Weight

the force exerted by gravity on an object.

High tides and low tides

occur due to the gravitational pull of the Moon and the Sun.

Gravitational potential energy

the energy held by an object because of its position relative to a gravitational field.

What are the four major ways light interacts with matter?

Emission, absorption, transmission, and reflection/scattering.

What is an example of emission?

A light bulb emitting visible light.

How does absorption occur with light?

When your hand absorbs energy from a light bulb.

What is transmission in the context of light?

Glass transmitting light, allowing it to pass through.

What is reflection/scattering?

When light bounces off a surface, as seen in a mirror.

Why is light considered an electromagnetic wave?

Because it consists of traveling vibrations of electric and magnetic fields.

What is wavelength in relation to light?

The distance from one peak of a wave to the next.

What does frequency refer to in light waves?

The number of peaks passing a point each second.

What is the relationship between wavelength and frequency?

They are inversely related; as frequency increases, wavelength decreases.

List the types of electromagnetic waves from lowest to highest frequency.

Radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

What are the basic components of an atom?

Protons, neutrons, and electrons.

What is the size of an atom?

Approximately 0.1 nanometers.

What defines the atomic number of an element?

The number of protons in its nucleus.

What is the atomic mass number?

The total number of protons and neutrons in the nucleus.

What distinguishes isotopes of the same element?

They have the same number of protons but different numbers of neutrons.

What is a molecule?

A group of two or more atoms that are chemically bonded together.

What are energy level transitions in electrons?

Changes where an electron rises or falls between energy levels.

What is a continuous spectrum?

A spectrum that shows a rainbow of colors, like that from an incandescent light bulb.

What is an emission line spectrum?

Light emitted at specific wavelengths depending on gas composition and temperature.

What is an absorption line spectrum?

A spectrum showing dark absorption lines over a continuous spectrum.

How can we identify elements in distant objects?

By matching unique light patterns from their spectra.

What does the Doppler effect describe?

The change in frequency and wavelength due to motion between the source and observer.

What does blue shift indicate in terms of object movement?

The source is moving towards the observer, causing shorter wavelengths.

What does red shift indicate?

The source is moving away from the observer, causing longer wavelengths. How does the eye control light entry?

What role does the lens in the eye play?

The lens bends light to form an image on the retina.

What is the focus in terms of light rays?

The focus is the point where parallel rays of light converge.

What is the focal plane?

The focal plane is where the image appears in focus.

How does a camera function similarly to the eye?

A camera has a small opening for light and a lens that bends light to focus it on a detector.

What affects the quality of images in cameras?

Exposure time affects image quality; longer exposure reveals fainter details but can overexpose bright areas.

What are pixels in modern detectors?

Pixels are picture elements in electronic chips divided into grids.

What is a reflecting telescope?

A telescope that uses a transparent glass lens to collect and focus light.

What is a refracting telescope?

A telescope that uses a precisely curved primary mirror to gather light.

Which type of telescope is more commonly used by professional astronomers?

Reflecting telescopes are more commonly used due to the need for high-quality glass lenses.

What types of rays can reach Earth's surface?

Visible light and radio waves can reach Earth's surface, while gamma rays and X-rays are blocked by the atmosphere.

Why are space telescopes necessary?

Space telescopes are needed to study the universe because certain rays are blocked by Earth's atmosphere.

How much greater is the light collecting area of a 6m telescope compared to a 3m telescope?

The light collecting area is four times greater because the power grows with the area.

What is the diffraction limit in telescopes?

The diffraction limit is a constraint on a telescope's angular resolution, affecting image sharpness.

Why does the Hubble Space Telescope obtain higher resolution images?

It is above Earth's atmosphere, which blurs and distorts light for ground-based telescopes.

What size must a radio telescope be to achieve the same angular resolution as a visible light telescope?

A radio telescope must be much larger due to the longer wavelengths of radio waves.

Where should a telescope designed for ultraviolet observations be placed?

It should be placed in Earth's orbit, as ultraviolet light is blocked by the atmosphere. Isaac Newton (1642-1727)

Newtonian physics

The basis for most physics today.

Newton's first law of motion

An object in motion will stay in motion (in a straight line) an objects at rest will stay at rest unless acted upon with an uneven force

Newton's Second Law

Force = mass x acceleration

Mass

the amount of matter in an object (kg)

Weight

A measure of the force of gravity on an object (N)

Newton's Third Law

For every action there is an equal and opposite reaction

Newton's Law of Gravity

F=GMm/r^2 (Every mass exerts a force of attraction on every other mass)

Earth's gravity

9.8 m/s^2

Moon's Gravity

1.6 m/s^2 (1/6 g Earth)

orbit

The path of an object as it revolves around another object in space. An object in orbit is accelerating toward the Earth but does not get closer to Earths surface due to Earth's curvature)

escape velocity

The velocity an object must reach to fly beyond a planet's or moon's gravitational pull.

escape velocity equation

v = √(2GM/r)

If you double the radius of a planet while keeping it the same mass, what happens to the escape velocity?

Increases

Tides

the regular rise and fall of the ocean's surface influenced by the moon's gravity pulling on earth

How many high tides are there a day on the coast of California

2 high tides

Why do objects fall at the same rate?

Because the acceleration due to gravity is the same for all objects near Earth's surface. Heavier objects experience more gravitational force than lighter ones, but their extra mass makes up for that.

law of universal gravitation

the scientific law that states that every object in the universe attracts every other object

Uranus

Discovered by William Herschel in 1781

Neptune

Discovered by gallello 1846

Pluto

Clyde Tombaugh 1930 Temperature Measures Atomic Motion

Low- atoms move slow

Absolute zero- atoms dont move

What Temp scale has the largest value?

Kelvin

Light as a wave

Light waves are tiny, Blue 400 nanometers, Red 700 nm.

Lambda is the symbol for wavelength

Frequency

the number of complete wavelengths that pass a point in a given time

Measured in Hz

Speed of Light, c

3.00 x 10^8 m/s

Speed of light in air is very close to the Speed of light in a vacuum.

All wavelengths travel at the same speed in vacuum.

Light slows down in water, glass

Short to long wavelengths

Gamma ray, x ray, ultraviolet, visible, infrared, microwave, and radio waves

Kirchhoff's Rule #1

A hot dense object emits a continuous spectrum. No gaps.

Kirchoff's Rule #2

A hot rarefied (not dense) gas emits a discrete or "bright-line" spectrum. Ex: neon lights

Kirchoff's Rule #3

When light having a continuous spectrum passes through a cool gas, dark lies appear in the spectrum. Dark lines characteristic of atoms in the cool gas.

Blueshifted

The Doppler shift toward shorter (bluer) wavelengths of light from an approaching object.

Redshifted

moving away