Astronomy Basics
- 1. Astronomy What You Really Need To Know Accompanied by a Worksheet
- 2. • Nebula: clouds of gas and dust. • Mercury has the smallest diameter and greatest average density. • Rocky object known as asteroids are located between Mars and Jupiter. • Mercury travels around the Sun in less time than it take for Earth to make one complete revolution. • Absolute Magnitude: a measurement scientists use to compare brightness of stars. • At any given time 50% of Earth is illuminated by the Sun.
- 3. • Earth is an inner planet. • The corona is the layer of the sun seen during a solar eclipse. • Jupiter has a fierce hurricane-like storm that is several times the size of Earth. • Life has flourished on Earth because we have liquid water. • Hydrogen is the main element of most stars. • The presence of sand dunes on Mars indicate the presence of winds on Mars. • When Earth’s orbit passes through the remains of a comet spectacular meteor showers are observed.
- 4. • Apollo 11 was the first manned-mission to land on the moon. • Fusion is the process by which the sun emits energy by converting hydrogen into helium. • The core of the sun is the most dense layer of the sun. • Venus is referred to as “Earth’s twin”. • One year equals one complete revolution of a planet around the sun. • Gravitational attraction between Earth and an object depends on distance and mass.
- 5. • Weight is dependent on gravity. • Mercury has no atmosphere and little gravity and is closest to the sun. • The gravitational pull of the moon causes tides on Earth. • The rotation of the Earth causes the sun to appear to rise and set. • Planets usually contain an atmosphere. • Solar winds blow a comets tail away from the sun. • Earth’s tilt causes seasons.
- 6. • We live in the Milky Way Galaxy. • The Milky Way Galaxy is a Spiral Galaxy. • Stars appear to change position during the night because the Earth is rotating on its axis. • Erosion does not occur on the Moon because there is no wind or rain.
- 7. 1. Why does a comet's tail point away from the Sun? – The solar wind blows the tail away from the Sun. – The comet's tail is following the path of Jupiter. – The Moon's light only shines on part of the comet. – It is being pulled by a nearby black hole.
- 8. 2. Earth's axis of rotation is tilted 23.5° relative to the plane of its orbit, which helps to cause – – high and low tides – the lunar phases – the seasons – day and night
- 9. 3. In addition to Earth's orbit, which planets' orbits are shown? – Mercury and Venus – Venus and Mars – Mars and Jupiter – Jupiter and Saturn
- 10. 4. Which planet has the shortest day? – Mercury – Venus – Jupiter – Saturn
- 11. 5. Based on the drawing above, what is the main reason that Venus would appear brighter at point Q rather than at point R as seen from the Earth? – More of the visible side of the planet is illuminated at point Q than at point R. – Light from the planet at point Q is less affected by the sun's gravity than at point R. – The planet is closer to the Earth at point Q than at point R. – The planet appears overhead against a dark sky when it is at point Q but not at point R.
- 12. 6. In the late 1920s, Edwin Hubble and Milton Humason determined the distance to a number of galaxies and the velocity of those galaxies relative to the Earth. The graph shows the early results that were obtained. What approximate ratio did the scientists calculate between velocity and distance based on these early findings? – 450 kilometers per second per one million light years – 150 kilometers per second per one million light years – 600 kilometers per second per one million light years – 300 kilometers per second per one million light years
- 13. 7. In 1912, an astronomer at Arizona's Lowell Observatory noticed that the lines in the spectra of most galaxies shifted toward the red end of the spectrum. Another American astronomer, Edwin Hubble, later interpreted this discovery as evidence that – – the largest galaxies are slowly engulfing their smaller neighbors – galaxies are moving away from each other in a constantly expanding universe – galaxies were once part of one huge megagalaxy – an explosion will one day result from the pressure building as the galaxies expand
- 14. 8. At what position would Earth be found in the solar system diagram shown below? – 1 – 2 – 3 – 4
- 15. 9. Which of the above evolutionary stages of a massive star is called a supernova? – 1 – 2 – 3 – 4
- 16. 10. According to this diagram, a lunar eclipse occurs only when the – – sun's rays are directly overhead – Earth is between the sun and the moon – moon is in the new moon phase – moon is between the sun and the Earth
- 17. 11. According to this chart, which planet will most likely have the highest temperatures? – Mars – Earth – Mercury – Venus
- 18. References • Astronomy Applets – http://www.ioncmaste.ca/homepage/resources /web_resources/CSA_Astro9/files/html/applet s.html