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A tribute to growing up, The Big Site of Amazing Facts showcases Unusual Interesting Facts about the world we live in that have been lost in time and space. We are your one stop for strange and unusual facts.

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Why is the harvest moon brighter than other full moons in other seasons?

Ordinarily, the mid-September harvest moon is no brighter than any other full moon, but it does provide more hours of moonlight.

In autumn, the orbital path of the Moon and its visibility in the sky combine so that it stays above the horizon for an unusually long time at the full moon and a day before and after.

The brightness of the Moon is determined by how much sunlight falls on it, which is pretty much constant; how much appears to be lit up from where we see it, from crescent to full; and how high it is in the sky. The higher the Moon is, the more light we see, because it has a shorter path through the dust and smog of the atmosphere.

In 1997, the harvest moon of September 15 was the brightest of the year, by a small margin, because it came within a few hours of perigee, the Moon’s closest approach to Earth.

The difference in brightness between the Moon’s closest approach and farthest point amounts to 12 to 13 percent. It was also the largest full moon in angular size; its apparent diameter, normally about 30 arc-minutes, was 32 or 33 arc-minutes.

The varying Earth-Moon distance is why solar eclipses are sometimes total, when the Moon completely blocks the Sun, and sometimes annular, with a ring of light visible around the Moon.

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When searching for extraterrestrial intelligence what kinds of signals are evidence of transmission by intelligent life?

Such a transmission might take many forms, but would probably encode mathematical formulas.

The reply would depend on the content; it would not be made by scientists, but would come after extensive international consultation.

As for verification, the main feature distinguishing signals produced by a transmitter from those produced by natural processes is their spectral width that is, how much room on the radio dial they take up. As far as scientists know, any signal less than about 300 hertz wide is artificially produced.

Other telltale characteristics might be coded information, like the message beamed from the Arecibo telescope in 1974, which included data like the senders’ location (third rock from the Sun, in the case of Earth). Another important test would be a confirming observation of the same signal at another radio telescope.

Once confirmed, the discovery would be announced based on a plan set up by six international space agencies. First, the scientific community would be notified through the International Astronomical Union and the United Nations. Then international authorities would draft a reply.

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What is used as a pole star in the Southern Hemisphere where navigators can’t see the North Star?

The closest thing to a south star for navigators south of the equator is a pair of stars in the Southern Cross, Crux Australis (or just Crux to astronomers).

Alpha Crucis (its brightest star) and Gamma Crucis (the third brightest) point almost straight to the south celestial pole.

The striking Southern Cross, which has four stars brighter than the second magnitude in a cross or kite shape, takes up only 68 square degrees of the sky.

The area defined by the Southern Cross has other interesting features, notably the Coalsack Nebula, which looks like a round blank spot in the sky but is actually a cloud of gas-laden dust that blocks the background starlight, and the Jewel Box cluster, designated NGC 4755, an open cluster of more than 100 stars surrounding Kappa Crucis, which is bright red in a modest telescope.

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When looking at the stars why can I see the fainter stars better out of the corner of my eye?

Because the eye has two kinds of receptors, cones for fine resolution and color and rods for dim light, and the rods tend to be located around the periphery, for viewing the edges of the field of vision.

Cones are extremely good at high definition and for precise positioning of pinpoints of light. Rods don’t give nearly as fine resolution and don’t distinguish colors, but are much more sensitive. In effect, rods serve as night-vision sensors.

The result is that when you go out at night, you can clearly see the bright stars and planets at the center of your eye, but you can see the fainter ones out of the corner of your eye. Astronomers call this averted vision.

For example, if they look with the unaided eye straight at a galaxy they know is there, they may not see it, but if they look off to one side, they can easily see the fuzzy gray patch that is the galaxy.

Cameras, too, tend to give up resolution and sensitivity to color when they achieve better sensitivity to low light levels.

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Why can’t you see the stars in photos or videos taken by astronauts?

Such pictures do not ordinarily show stars because the stars are not bright enough in comparison to the nearby Sun and the things it shines on.

Virtually all of the astronaut photos are of objects brightly illuminated by the Sun. To capture them on film without overexposing the image, you need a relatively short exposure, which does not provide enough time for the film to capture images of stars.

If there is no other strong light source in the picture, however, a photo can show stars.

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What would kill you if you fell into a black hole?

You might not die right away, but you would eventually be pulled apart by the force of gravity.

As you fell in and even afterward, you might not lose consciousness, but the pull of gravity on your feet would be stronger than on your head, and you would be stretched, then torn apart.

The difference in force is called the tidal force and is like that in the ocean, except in more extreme form. The force would be less if it was a big enough black hole; in a small black hole it might kill you before you disappeared beneath the event horizon, the edge of the hole.

But even in a larger black hole, the tidal force always gets you in the end. Once you fall in, you can’t avoid falling toward the center, and the force would kill you before you reached the center. How long it would take depends on how big the black hole is.

If it was big enough so that the tidal force didn’t kill you before you fell in, you might have an hour or several hours before being torn apart. In a small one, such as one that forms when a star collapses, you wouldn’t have much time, perhaps a thousandth of a second.

That would happen with a run-of-the-mill black hole, like those that might be found in the Milky Way Galaxy.

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Is the universe rotating or spinning?

Most astronomers would say no. There is no known mechanism that would give the universe so much angular momentum, or spin, at its beginning, and few mechanisms for adding spin later.

To know for sure if the universe rotates, scientists would need to know the velocities of millions of galaxies, over all regions of the sky and out to very great distances.

Analysis of these velocities would be necessary to see if they indicated a common center about which galaxies were rotating, and a sense of direction on average.

Since it may be a while before the velocities of millions of galaxies are known, astronomers are trying to answer a simpler question: Are there regions of space toward which large numbers of galaxies are moving as a group?

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Are all stars burning out and are new ones forming?

Stars are being born as well as dying, but the rate varies greatly from galaxy to galaxy.

Stars form from huge clouds of dust and gas. If a cloud begins to contract because of its own gravity, its interior heats up as gravitational energy is converted to heat energy, reaching millions of degrees, and nuclear reactions begin that change one element into another, releasing energy.

The pressure tends to expand the cloud back out, but eventually equilibrium is reached. That is essentially what a star is, a mass of gas at equilibrium between inward pressure from gravity and outward pressure from nuclear reactions.

A star has a finite lifetime because it is burning fuel. For 90 percent of its life, it burns hydrogen into helium. When the hydrogen is used up, the pressure decreases, but gravity never disappears, so the star contracts until the temperature climbs again, this time reaching hundreds of millions of degrees, while reactions convert helium to carbon and oxygen.

The star can then remain stable for a briefer time. Eventually the star dies, when the reactions no longer produce energy, but only consume it.

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Why do gnats and mosquitoes and other annoying insects get together in swarms?

Many insect species swarm, both the beneficent (like honeybees) and the irritating (like mosquitoes).

In many cases, springtime swarms consist of groups of males all looking for suitable mates. Pheromone signals probably keep the group together. As insect mating, egg laying, and hatching tend to take place in synchronized waves, it is not surprising that a generation emerges with one goal.

Formation of mosquito swarms, which vary from species to species, can depend on variables like available space, lighting conditions, and winds.

Mosquito swarms often focus on a defined point like a bush or hedge, where the air is undisturbed, and there are even reports of swarms that form over the head of a person and follow him around as he slowly walks.

Other large insect groups, all moving in the same general direction, may be migratory insects, like monarch butterflies, or social insects setting up new colonies.

The next time a cloud of mosquitoes buzzes around your head, count yourself lucky. The desert locust, Schistocerca gregaria , can blacken the sky for miles around. A swarm in Kenya in 1954 was estimated to cover more than 77 square miles.

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How many insects and other arthropods might you find in a northeastern backyard?

The number of individuals and species would depend on many variables, like soil condition and chemical use, but if the first few inches of soil were included, the totals might be impressive.

One survey of backyard insects in the 1930s collected 1,402 species, including 467 butterflies and moths, 258 flies, 259 beetles, and 167 wasps, bees, and ants, from a 75-by-200-foot garden in a northeastern New Jersey suburb. The survey did not include arachnids like spiders and mites.

A suburban lawn is a monoculture, a single-crop field, and since, in general, biodiversity increases with complexity, the number of large, easily visible arthropod species on the surface of the soil or in the grass itself would be fairly low. One estimate is 25 to 50, with the number greatly reduced if pesticides had been used.

However, if the fauna of the litter layer and the top few inches of the soil is included, a survey could find huge numbers of individuals of springtails and mites, as many as tens of thousands per square yard.

Up to 50 species of springtails per square yard have been found in woodland soil.

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