Mon Nov 25, 2024 SOUNDS IN OUTER SPACE
I remember my 8th grade science teacher telling us that Star Trek was unrealistic because every time the starship Enterprise sailed by during the opening credits, it would go, “whoosh!” And that was wrong, because there is no air in space to make any kind of sound at all. Now it’s true that sound waves need a transmitting medium to be heard. But what if outer space did have a transmitting medium? When robotic spacecraft passed Jupiter and Saturn, the emissions from their magnetospheres were converted into sound, making a very eerie kind of “music.” NASA calls this, “data sonification.” Likewise, if a spacecraft flies through a particle field, like Saturn’s ring system, or through the dust tail of a comet, the sounds of those mini collisions are “heard,” and transmitted back to earth. This is the true, “music of the spheres!”
Tue Nov 26, 2024 BLACK HOLES PROPOSED
On November 26, 1783, John Michell proposed the existence of black holes, suggesting that there might be super-dense stars with powerful gravitational fields that could keep light from leaving them. This idea was ahead of its time, coming as it did shortly after the American Revolution. But he was right, and in the past several decades we have found evidence for these cosmic dead ends in space. There is a black hole above us tonight. Vega, Altair and Deneb, three bright stars that form the Summer Triangle are in the west sky this evening. We think there's a black hole in the middle of the triangle – it’s called Cygnus X-1. We can't see it directly; these things are literally out-of-sight, but something’s there, because an incredible amount of x-rays pour out of this region, made by the black hole's gravity.
Wed Nov 27, 2024 HERCULES’ AUTUMN ZODIAC
The adventures of Hercules are displayed by the constellations. The zodiac reveals many of his twelve great labors. Soon to set after the sun are the stars of Sagittarius the archer. This centaur is a depiction of Hercules’ teacher, Chiron. Well-placed in the south are a scattering of stars which mark Aquarius, the Water Carrier. This is symbolic of Hercules’ releasing the flood of river waters that cleaned the Augean stables. High in the east is Aries the Ram, a representation of the golden fleece, which Hercules pursued with his good friend Jason while he was between labors. Nearer toward the eastern horizon is Taurus; this was a wild bull which Hercules subdued in a kind of a “capture and release” program. There are more constellations connected with Hercules, but they won’t show up in our evening sky until next month.
Thu Nov 28, 2024 WHY BUY A TELESCOPE?
You can spend lots of money buying a telescope and then be unhappy with the results. Before you buy one, ask yourself: what do you expect the telescope to do? Most small telescope views fall far short of the incredible images that we get from great observatories or space telescopes. So why buy a telescope? Well one of the principle joys of the telescope is the excitement of finding these objects in the sky, and knowing that they really are out there. A good starter telescope is a Newtonian reflector with a 6-inch mirror on a Dobsonian mount, which uses big one and a quarter inch eyepieces. Such a scope should cost between 200 – 400 dollars. Begin your research on the internet, or e-mail me at jbell@irsc.edu for advice.
Fri Nov 30, 2024 THE MOON AND TIDAL LOCKS
Just as we experience daylit and dark periods on earth, so the moon has both day and night. But the moon spins slowly; a lunar day lasts two weeks, followed by two weeks of lunar night. The moon’s rotation period matches its revolution, so it rotates once for every one orbit. This is called a tidal or synchronous lock, an effect of the earth’s tidal pull on the moon, which has slowed its rotational speed to match its revolution. Because of this we can only see half the moon (lunar nearside;) the farside of the moon (sometimes wrongly called “the dark side,”) can never be seen from earth. Or as Pink Floyd tells us, ”There is no dark side of the moon; matter of fact, it’s all dark!” But the sun lights up the dark side, sorry, farside, just as much as lunar nearside.
