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Questions and Answers:
7/21/11: Perseid Meteor Shower
Q: When are the Perseid meteors visible this year?
A: The annual Perseid Meteor Shower takes place for a couple of weeks surrounding their peak activity date. This year, the Perseids reach their peak on the night of August 12th leading into the morning of August 13th. As with most meteor showers, the Perseids are best viewed after midnight, ideally around 3:00 AM.
6/23/11: Meteorite or Meteor-wrong?
Q: How do I determine if the rock I have is or isn't a meteorite?
A: Here are a couple of links to sites with information and experts. They may be able to help you. 1) http://www.meteorflash.com/ (Mare Meteoritics, Mike Martinez, former Chabot meteorite curator); 2) http://www.meteorite.com/Meteorite_Identification.htm (Meteorite.com, Meteorite Identification).
Q: When pumping water up high, does it make any difference in power consumption if it is pumped right up in one stage, or if it is done in stages with intermediate pools?
A: From the standpoint of how much energy moving the water up (against gravity) takes, it does NOT matter if you do it all at once or in stages. Raising a unit of water vertically by a certain distance requires a specific cost of energy, equal to the weight of the water times the vertical distance. Any difference in energy consumption between two different schemes of getting the water uphill will be in the efficiency of the method—that is, how much or how little energy is WASTED in the process because of non-ideal efficiency (which is usually the case).
9/15/10: Planetarium Software
Q: What is a good piece of software or online resource for displaying the appearance of the sky from a given location at a specific time and date?
A: As Freeware goes, my favorite is "Home Planet," which can be downloaded from www.fourmilab.ch/homeplanet/. Set your location, time, and date and the select view sky.
8/24/10: Orion's Belt:
Q: What month can you begin to see Orion's Belt?
A: If you're an early riser, you can begin to see Orion, and his Belt, rising in the east as early as August. Here at the end of August you can see the Belt low in the eastern sky at 5:00 AM DST. As we move into Autumn, Orion will rise earlier and earlier, and by mid to late December it is rising after 7:00 PM and high in the south at midnight.
8/18/10: Light in the Eastern Sky:
Q: Everynight for about the past two weeks there is a very bright light that appears at around 11:00pm. I live in Concord, CA and the object is visible in the eastern sky. It seems way too close and bright to be a star. It seems relatively stationary but appears to very slowly rise higher in the sky. Do you have any idea what we are looking at? My son was the first to see it about two weeks ago. He was certain it was a UFO but we have seen it just about every night since. The first night he saw it, he swore it was doing figure eights in the sky but I am highly doubtful.
A: Very likely what you are seeing is the planet Jupiter. At around 11:00 PM, Jupiter is slightly south from the eastern point, and about 18 degrees (roughly two fist-widths) above the horizon. Jupiter is getting close to opposition - the point when we are closest to it - and so is at its brightest right now. A small telescope, or maybe even a good pair of binoculars, will reveal Jupiter as a bright disk with a string of up to four starlike dots - its four large moons, the Galileans--that change their positions from night to night. As for figure-eights, sometimes a star or planet can appear to move about a bit; part of this may be atmospheric turbulence bending the object's light (the typical "twinkling" of a star - though planets are not observed to twinkle as much), and part may be due to an optical illusion we can experience when we see a dot that is not close to other reference points (like the horizon).