Astronomy

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sun spots

Back 1

These are dark temporary spots on the photosphere. These are caused by magnetic activity which acts to reduce the temperature there, making the area darker compared to hotter surroundings.

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solar flares

Back 2

They are violent, but short-lived eruptions of very hot gases and are charged particles that occur near sunspots.

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solar prominence

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Immense clouds or loops of lower energy glowing gas that extends thousands of kilometers from the solar surface into space and are lasting.

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solar wind

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the solar wind is a stream of charged ejected from the upper atmosphere of the sun.

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sun

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A huge shinning ball that produces tremendous light + heat and other energy forms (composed of hot gas substances called plasma) It is also our closest star.

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core

Back 6

the innermost layer of the sun and is the source for all its energy. the energy is the result of a reaction called nuclear fusion in which hydrogen atoms fuse to form helium atoms. It also is the hottest part of the sun.

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radiative zone

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It is the first layer that surrounds the core which it receives energy from.

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convection zone

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Region where hotter substances (less dense) rise and colder substances (more dense sink)

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photosphere

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This is the visible surface of the sun and is where energy from the core is emitted into space.

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chromosphere

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This is just above the corona. It is the inner atmosphere of the sun and is about 2000 km thick.

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corona

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This is the outer part of the sun's atmosphere. It extends millions of kilometers into space. It is best seen during a solar eclipse.

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earth's axis

Back 12

It is an imaginary straight line joining the north and south poles. If this continued north into space it would pass almost through "Polaris" the north star. Since it is so close it appears not to move.

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north celestial pole

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The place in space where the earth's north pole points.

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south celestial pole

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The place in space where the earth's south pole points.

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earth's rotation

Back 15

the spinning of an object around it's axis. This rotates counter clockwise and one rotation takes 24 days. The motion causes celestial objects to appear to rise in the east and set in the west.

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effect of the earth's rotation

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We do not notice the speed of this but do notice its effect: day and night. As it rotates the portion facing the sun experiences ay while the portion facing away experiences night.

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earth's tilt

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This is tilted as 23.5 degrees from the vertical, relative to the plane of earth's orbit.

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consequences of the earth's tilt

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This causes the amount of sunlight that areas of the earth receive to change throughout the year which causes different seasons. In the northern hemisphere, the earth is actually closer to the sun in the winter, but tilts away and farther in the summer but tilts toward.

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earth's revolution

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the movement of an object around another. This revolves around the sun at 29.8 km/sec following and elliptic path which takes one year to complete.

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solstice

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The longest and shortest periods of daylight which occur when earth is most tilted towards or away from the sun. This happens twice a year a summer _______on June 22 and a winter _______ on December 22.

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equinox

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The time of year when the hours of daylight and darkness are equal. This happens twice a year: Vernal (spring) _____ on March 21 and Autumnal on September 21.

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changing seasons

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This is responsible for the change in temperature and amount of daylight hours. This is due to the sun's rays being spread over smaller and larger areas.

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summer

Back 23

when the northern hemisphere tilts toward the sun, it experiences more hours of sunlight each day at a stranger intensity making the temperature higher and we experience summer. the sunlight is more intense because it spreads over a smaller area of earth's surface (hits more directly) and whatever is facing the sun will get more sunlight.

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eccentricity

Back 24

the change in shape of the earth's orbit. Following a 100,000 year cycle, the shape's of the earth's orbit varies from being circular to more elliptical. this is caused by the gravities of other planets. the greater the eccentricity, the less circular the orbit.

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tilt

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the ____ of the earth's access, with respect to the plane of its orbit about the sun. the tilt can range from 22.1-22.5.

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precision

Back 26

the changing of direction of earth's axis. the earth is actually wobbling, meaning that as it rotates, its access slowly turns, pointing in different directions. This wobble is very slight and traces a circle every 26,000 years. In 12,000 years, our axis will point to vega instead of Polaris.

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astronomy

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the study of everything that is beyond our earth.

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galaxies

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a collection of billions of stars, gas, dust and planets. earth is part of the milky way galaxy.

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solar system

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the sun and all the objects that travel around it.

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celestial bodies

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any object in space.

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planets

Back 31

large celestial objects that orbit around the sun.

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moons

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a type of satellite which is a celestial object that travels around a planet or dwarf planet in a closed path called an orbit.

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dwarf planets

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orbits the sun, spherical shape, smaller than some of the objects that cross their orbit. do not dominate their orbit.

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stars

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massive of bodies composed of hot gasses. radiate large amount of energy.

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comets

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large chunks of ice, dust and rock that orbit the sun. as it nears the sun, it is warmed and the frozen materials become gases and form a bright glowing tail.

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asteroid belt

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ring of asteroids that orbit between mars and Jupiter.

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asteroids

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small rock and metal objects that orbit the sun.

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meteoroids

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a small piece of metal or rock (in space).

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meteors

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a meteoroid that is trapped by earth gravity that is pulled into earth's atmosphere. as it falls, friction with air particles causes bright streaks of light across the sky.

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meteorites

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meteors that collide with earth's surface and cause craters.

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eclipses

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astronomical event when one celestial object blocks or darkens the view of another celestial object.

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solar eclipse

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This occurs when the moon passes between the sun and the earth. During this, the moon is aligned between the earth and the sun, and the sun is fully/partially blocked from the earth by the moon. During new moon.

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a total solar eclipse

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Moon completely covers the sun. occurs approximately every 2 years.

why it is not so frequent: The Moon'sorbits inclined (tilted)at more than 5 degrees to the Earth's orbit around theSun, so its shadow at the new moon usually misses Earth.

Front 44

partial solar eclipse

Back 44

the moon partially covers the sun (earth, the moon and the sun do not perfectly align)

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annular eclipse

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Moon appears smaller than Sun and a bright ring of sunlight remain visible

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umbra

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shadow from theMoon where all light is blocked (only a few dozen kilometres wide)

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penumbra

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shadow from the Moon where some light is blocked.

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lunar eclipse

Back 48

Occurs when the Moon, Earth and Sun are aligned and the Moon passes directly behind the Earth. Earth casts a shadow on the Moon (Moon is in Earth’s umbra or penumbra). This is during a full moon. There are 0-3 lunar eclipses each year.

The orbit of the moon is tilted by 5°so itusually passes above or below the Earth’s shadow

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tides

Back 49

The rising and falling of the surface of oceans are caused by the gravitational pull of the moon and sun (to a lesser extent). The Moon pulls the water towards it causing a bulge of water on Earth from the side facing the moon and the opposite side. ·This gravitational pull results in two high tides and two low tides each day- roughly 6 hours in between high and low tides.

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spring tides

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Sun and Moon working together either on same sides of Earth
 and opposite sides of Earth. These occur during New Moon and Full Moon
 (when the sun, the moon, and earth are aligned). Combined forces of Moon & Sun cause very high tides

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neap tides

Back 51

Sun and Moon working against each other. Perpendicular (90o) to each other with respect to Earth. Neap tides occur during the first and third quarter. ·Forces of Moon & Sun counteracting one another causes weaker tides (smaller high tides)