ES Ch 24 Studying the Sun

EM radiation

includes gamma rays, x-rays, UV light, visible light, infrared radiation, microwaves & radio waves

EM spectrum

arrangement of waves according to their wavelengths & frequencies

speed of light

How fast do EM waves travel?

wavelength

distance from one crest to the next

crest

Highest point of a wave

trough

Lowest point of a wave

visible light

narrow band of EM radiation the human eye can see

prism

separates visible light into component colors in order of wavelengths

photons

light in the form of stream of particles

spectroscopy

study of properties of light that depends on wavelength

continuous spectrum

What type of spectrum is produced by an incandescent light bulb?

absorption spectrum

produced when visible light is passed through relatively cool gas under low pressure

emission spectrum

produced by hot gas under low pressure

chemical composition

Why do scientists study the spectra (spectrum) of stars?

doppler effect

refers to perceived change in wavelength of wave that is emitted from source that is moving away or toward an object

redshift

What shows that light source is moving away from us?

blueshift

What shows that light source is moving toward us?

optical telescope

collect as much light as possible & contain mirrors, lenses, or both to produce an image

refracting telescope

uses a lens to bend & concentrate light from distant objects

chromatic abberation

property of lens where light of different colors is focused at different places

reflecting telescope

use a concave mirror that focuses the light in front of a mirror, rather than behind it, likes a lens

sharper image with more detail

What does resolving power do with telescopes?

radio telescope

focuses incoming radio waves on antenna, which absorbs & transmits these waves to amplifier, just like radio antenna

radio interferometer

several radio telescopes wired together in a network

space telescope

orbit above Earth's atmosphere & thus produce clearer images than Earth-based telescopes

Hubble

first space telescope, built by NASA, & put into orbit around Earth in 1990

extrasolar planet

planet in orbit around star other than sun

Chandra X-Ray Observatory

NASA uses to study (x-rays) objects like black holes

black hole

object whose gravity is so strong that visible light cannot escape them

Compton Gamma Ray Observatory

used to study both visible light & gamma rays emitted by black holes & other objects in space

James Webb Space Telescope

studies infrared radiation & able to detect IR from stars & galaxies that formed early in history of universe

photosphere

radiates most of sunlight we see & is visible "surface" of sun

chromosphere

relatively thin middle layer of hot gases a few thousand km thick

corona

outermost portion of solar atmosphere that is only visible when photosphere covered

solar wind

stream of protons & electrons ejected at high speeds from corona that travel through solar system

aurora borealis

What occurs when Earth's magnetic field interacts with solar wind?

sunspots

dark regions on surface of photosphere

prominences

huge cloudlike structures consisting of chromospheric gases

solar flares

brief outbursts that normally last about an hour & appear as sudden brightening of region above sunspot cluster

nuclear fusion

where sun produces energy in core by converting 4 hydrogen nuclei into nucleus of a helium atom, releasing tremendous amount of energy

core

Where does fusion take place in sun?

pressure from fusion & gravity

What two forces keep sun in balance?

radiation zone

region of highly compressed gas where energy is transferred to individual atoms

convection zone

outer layer of sun's interior

What color of visible light is the longest?

red

What color of visible light is the shortest?

violet

granules

What is the grainy appearance of the sun's surface due to moving column of gases?

radiation zone

What layer of the sun's interior is where light is reabsorbed & reemitted multiple times?