Do you know that stuff is moving around out there?


On Monday, February 26, our Periscope Trivia Contest was about movement in space. Here are the questions. Below are the answers and winners. How many questions can you answer correctly?


  1. During retrograde motion, where will a planet rise?

  2. Earth’s speed changes as it orbits the Sun. Which of Kepler’s Laws describes this change?

  3. Galileo’s observation of the phases of what planet convinced him that the Earth orbits the Sun?

  4. What do we need since the Earth does not go once around the Sun in exactly 365 days?

  5. The Moon orbits the Earth once every 27,3 days. How long does the Moon take to rotate once time on its axis?

  6. On a given day, one is likely to see the most meteors after what

    Martian basalt, found in Sahara, shock features, impact smelt, but no fusion crust


  7. Which part of the Sun experiences the longest sidereal rotation?

  8. How many years does it take for our Solar System to orbit the Milky Way Galaxy one time?

  9. Hubble Law, the relationship between the distance of a galaxy and redshift, is currently estimated to be about how many km/sec/Kpc?

  10. What do we call the concentration of matter in the direction of the constellations Hydra and Centaurus, that may be pulling surrounding galaxies toward it?


All models are wrong, but some are  useful.                   -George E.P. Box
  1. East…………………speear40

      Observing from the surface of the Earth, planets always rise in the East.

  1. Second Law……..macizmankind1

      When Earth is closer to the Sun (November thru March) we move faster than when we are more distant (June thru August)

  1. Venus…………….TooBokut

      Galileo’s telescope made it possible for him to be the first to see the phases of Venus.

  1. Leap year………..TooBokut

      We add a leap day every four years, but we skip Leap Years in years evenly divisible by 400.

  1. 27.3 days…………jacobsparks24

First quarter Moon.. The dark area to the left is in night.

      Because the orbital period is 27.3 days, as is the rotational period, we see only one side of the Moon.

There’s a small amount of wobble, letting us see maybe 10% more surface area, but this near side is what we get to admire.

We see at least a little of the dark side of the Moon anytime it;s not full.  If you are standing on the Moon and the Earth is in your sky, the Earth will continue to hang in that same spot, day after day, month after month, year after year,

  1. Midnight……… ..tllc704

      From Midnight to 6 am is the best time. Like looking at the front windshield of a car driving thru rain.  Also, we must be before 6 am because the bright sky tends to hide the shooting stars.

  1. Pole …………Speear40

      The solar equator region takes about 25 days to rotate once, the mid latitudes take about 27-28 days, the poles take 33.5 days

  1. 240 million years……….CAPTAIN-DELTRON

      And we are only about half way from the core to the edge of the disk.

  1. 75………..thomasures

      So 75 new kilometers of space are appearing each second per megaparsec. The Andromeda Galaxy is about one Mpc from us.

  1. The Great Attractor…………..CAPTAIN-DELTRON        5 X 1016 Solar Masses, about 150 million Light Years away


Winners Get Eternal Glory

Name…………… number of correct answers

Speear40……… 2







Leaders: make a contribution in the next 30 days to one of my charities listed, and I will match it, up to $100. Tell the charity to contact me about your contribution.

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