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Sharpen Your General Knowledge

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Shamim Ansary:
Why do Fireflies and Lightning Bugs Glow in the Dark and what causes it?

Fireflies glow in the dark to attract mates. Males fly around flashing the world in a pattern of dots and dashes that is very specific to their species.

Female fireflies wait until a male flying nearby flashes the correct signal for their species, and in return, she flashes him with her own light. They meet and create beautiful luminescence together.

Light production in fireflies or lightning bugs is due to a type of chemical reaction called bioluminescence. This process takes place in specialised light-emitting organs, usually on a firefly’s lower abdomen or belly. Enzymes, in the presence of magnesium ions and oxygen produce light.

The enzyme is also useful in the medical industry.

The females of some firefly species prey on the males of other species. They lure the males by imitating the mating signals of the other species.

A oblivious suitor flying too close gets eaten.

Shamim Ansary:
Is the Weather Warmest When the Earth Is Closest to the Sun?

Surprisingly, the earth’s distance from the sun has nothing to do with weather!

The earth’s path around the sun is not a perfect circle, but an ellipse, or egg shape. The earth is actually nearest the sun around January 2, when it’s “only” 91,402,000 miles away. This point is called the perihelion. At the earth’s aphelion, or farthest point from the sun, it’s 94,510,000 miles away. And this point falls around July 5.

Why is our weather coldest when the earth is closest to the sun? Because weather is determined mostly by the tilt of the earth’s axis at various times of the year.

When it’s winter here, the earth is tilted in such a way that much of the sun’s radiation reaches us at an angle, and bounces off our atmosphere. In summer, the sun’s rays reach us more directly, and therefore the weather is warmer. Also, in winter the days are shorter, and much of the sun’s heat is reflected off the earth by snow.

The earth doesn’t travel around the sun at a constant speed, either; the speed varies at different points in the earth’s orbit!

Shamim Ansary:
Why Do Some People Snore?

When you are asleep and relaxed, and breathing through your mouth rather than through your nose, the air coming out causes your soft palate, the tissue at the back and top of your mouth, to flutter back and forth. This fluttering, or vibration, makes a sound called a snore. Often this vibration causes the cheeks, lips, and nostrils to vibrate as well, causing an even louder snore.

Although many ways have been tried to stop snoring from tying a bandage from the chin to the top of the head to keep the mouth closed, to actually removing part of the soft palate, no one has found a sure-fire method. However, some people claim that if you sleep on your side rather than on your back, you are less likely to snore. Nobody knows why, but men snore more than women and children.

The loudest snore recorded has been measured at 69 decibels, or almost as loud as a pneumatic drill!

Shamim Ansary:
How does latitude affect or determine the climate on Earth?

Latitude helps determine the temperature of a locale. Since one of the most important factors of climate is the amount of energy, or radiation, received from the Sun (heat), latitude plays a critical role.

Climatologists (people who study climate) use the word insolation for energy that reaches Earth from the Sun. The word combines syllables from the phrase incoming solar radiation. Sunlight is the obvious sign of insolation, but the Sun’s radiation reaches the earth on a cloudy day too. The angle and duration of insolation, which translates into surface temperature, changes depending on latitude.

Because Earth is spherical, when it orbits the Sun, the Sun’s rays hit Earth’s surface directly at the equator and at angles near the poles. Direct insolation is stronger than slanted contact.

Earth also tilts on its axis, so when the Southern Hemisphere is closer to the Sun, it has more hours of daylight than the Northern Hemisphere, and vice versa. At the equator, the hours of night and day remain 12 hours each. But most of us have experienced the shorter days of winter and the longer days of summer that come from Earth rotating at a tilt.

Latitudes that receive direct insolation for many hours a day tend to have warmer climates, such as at the equator. Latitudes toward the North and South Poles get angled insolation for fewer hours overall, and have colder climates.

The longitudinal angle of New York City is 74° west, making the latitudinal and longitudinal coordinates for New York City 40° north and 74° west.

Shamim Ansary:
Why are summer days longer than winter days?

Summer days longer than winter days the same reason that Earth has seasons: because Earth’s axis is tilted in relation to the Sun.

If the axis were straight up and down, different parts of the world would still have different lengths of daylight and darkness, but they would remain constant throughout the year.

When the Northern Hemisphere, or half, of Earth is tilted toward the Sun, the Sun’s rays hit it more directly.

The more direct—and therefore warmer—sunshine creates summer in the Northern Hemisphere. The tilt of Earth also makes the Northern Hemisphere experience longer days during this time, and the Sun appears to pass higher in the sky.

Six months later, Earth has moved halfway through its orbit, and the Southern Hemisphere is tilted toward the Sun. This means it is summer in the Southern Hemisphere and winter in the Northern Hemisphere.

You can see the change in the angle of the Sun very gradually over the course of several months. In the Northern Hemisphere, the Sun climbs higher in the sky each day as summer approaches, until one day—on or about June 21—it seems to stop getting higher.

After that, it drops lower each day as winter comes closer. Then it stops—on about December 21—and begins to climb higher again. June 21 is called the summer solstice, or “summer sun standing still”; December 21 is the winter solstice, or “winter sun standing still.” In the Southern Hemisphere, summer and winter are reversed.

Earth is divided into two sets of hemispheres. The equator divides the Northern and Southern Hemispheres.

The Eastern and Western Hemispheres are divided by the 0° meridian, or the prime meridian, on one side of the globe and the 180° meridian on the other (both not shown).

The two dotted lines show the tropics of Cancer (north of the equator) and Capricorn (south of the equator). Within these two imaginary lines the Sun’s rays are strongest.

You should never look directly at the Sun. The light is so powerful that it could damage your eyes.

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