Space Chapter 8

radiation consisting of electromagnetic waves that travel at the speed of light (such as visible light, radio waves, and X-rays)

A telescope that uses a lens to collect the light from an object

A telescope that uses a mirror to collect the light from an object

An artificial (human-made) object or vehicle that orbits Earth, the Moon, or other celestial bodies; also, a celestial body that orbits another body of larger size (for example, the Moon is Earth's natural satellite)

Observatories that orbit other celestial objects

The theory that describes how stars and planets form from contracting, spinning disks of gas and dust

A celestial body made of hot gases mainly hydrogen and some helium

a cloud of gas and dust in outer space, visible in the night sky either as an indistinct bright patch or as a dark silhouette against other luminous matter.

A hot, condensed object at the centre of a nebula

The process of energy production in which hydrogen nuclei combine to form helium nuclei

The surface layer of the Sun

An area of strong magnetic fields on the photosphere

A stream of fast-moving charged particles ejected by the Sun into the solar system

a brief eruption of intense high-energy radiation from the sun's surface, associated with sunspots and causing electromagnetic disturbances on the earth, as with radio frequency communications and power line transmissions.

Without the heat and light of the sun, life as we know it could not exist on the earth. Since solar energy is used by green plants in the process of photosynthesis, the sun is the ultimate source of the energy stored both in food and fossil fuels. Solar heating sets up convection currents, and thus is the source of the energy of moving air. Falling rain also owes its energy to the sun because of the relation of solar radiation to the water cycle.

A star's total energy output per second; its power in joules per second (J/s)

The magnitude of a star that we would observe if the star were 32.6 light years from Earth

An optical instrument that produces a spectrum from a narrow beam of light, and usually projects the spectrum onto a photographic plate or a digital detector

Certain specific wavelengths within a spectrum characterized by lines; spectral lines identify specific chemical elements

A graph that compares the properties of stars

A narrow band of stars on the H-R diagram that runs diagonally from the upper left (bright, hot stars to the lower right (dim,cool stars); about 90 percent of stars, including the Sun are in the main sequence

A small, dim, hot star

A massive explosion in which the entire outer portion of a star is blown off

A star so dense that only neutrons can exist in its core

Consume their hydrogen slowly over a period that may be as long as 100 billion years. As they age they slowly lose mass becoming a very faint white dwarf. They no longer produce energy but are incredibly hot, taking tens of billions of years from them to cool down.

Consume their hydrogen faster than low-mass stars. When their hydrogen is used up, the core collapses. As the core contracts, the temperature increases and the outer layers begin to expand. The expanded layers are cooler and appear red called a red giant.

Consume fuel faster than intermediate-mass stars and die more quickly and more violently. Heavier elements form by fusion and the star expands into a supergiant. Iron forms in the core and the core collapses violently and a shock wave travels through the star. The outer portion of the star explodes producing a super nova. A super nova can be millions of times brighter than the original star was.

The remnant of a supernova explosion with a gravitational field so strong that nothing can escape its pull.