A meteoroid that survives passing through the atmosphere without disintegrating is then called a “meteorite.”  Most meteoroids do not survive their journey through the Earth’s atmosphere and disintegrate into very small particles.  It is estimated that each day the Earth gains over a thousand ton of mass from the fall of tiny meteorites.

When can meteors be seen?

Every day millions of small particles enter the Earth’s atmosphere and cause meteors.  Most meteors are so brief or small that they go unnoticed.  Most meteors can only be seen at night, although some a bright enough to be visible during the day.  Small meteors, as small as pebbles, might appear for a second or two before disappearing, while larger ones stay visible longer and sometimes appear brighter as they burn up while disintegrating.  A very bright meteor is called a fireball.

A meteor’s altitude is usually within the 75 to 100 kilometer range in the atmosphere, or the Earth’s mesosphere.  A meteor is visible to an observer around 65-120 kilometers above the Earth’s surface.

What creates a meteor?

The bright light that is a meteor is the result of heat produced by a meteoroid’s entry into the atmosphere.  The ram pressure, or pressure exerted by the meteoroid moving at high velocities through the atmosphere, generates heat.  This pressure then heats the meteorite and the air molecules around it.  The surface of the meteoroid reaches high enough temperatures to vaporize some of the atoms and molecules on it as well as atmospheric gases around the meteoroid.  These heated, ionized particles form the trail of glowing vapors that we see as a meteor.   Meteors appear very briefly because the vaporized gases in the bright streak cool and disperse rather quickly.

Where do meteoroids come from?

The use of “meteor” to refer to the actual cosmic rocks is actually incorrect and not technical; these celestial objects are actually meteoroids.  Where do meteoroids come from?  A scientist would tell you they come from asteroids, or some come from comets, and some from the Moon or Mars.

What are meteor showers?

Though millions pass through the Earth each day, throughout the year an unusually large amount of meteors may occur at the same time.  This occurrence is known as a meteor shower.  Meteor showers sometimes occur when the Earth passes through remnants of a comet that passed through while orbiting the Sun.

What are meteors made of?

Meteors are made of vaporized and ionized gas trails of meteoroids.  Meteoroids and meteorites are made of minerals rich in various compositions of silicon, sodium, copper, potassium, iron, and nickel.

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The meteorite has gained its fame from one of the world’s best-loved superheroes, Superman. The Man of Steel’s Achilles’ heel is the mineral kryptonite – and the villains in his life have probably thanked all the meteorites that encapsulated the small substance.

But what is a meteorite? And where does it come from?

The universe consists of heavenly bodies – mainly planets, galaxies, stars, and asteroids (rocky, metallic objects that look like rocks; also known as minor planets). Some of these asteroids take a one-way trip to Earth – should they decide to continue their suicidal collision course, they become meteoroids. When a meteoroid touches our atmosphere, the friction causes it to ignite, and like a match, and burns it.

Now by theory, the meteoroid is supposed to burn up completely. However, in most cases, it doesn’t. The leftover meteoroid has no other choice but to land on the Earth’s surface. It manifests itself as a falling or shooting star (at this point, it is now called a meteor), touches ground and voila! A freshly-landed meteorite is born.

Some of the meteorites have been analyzed. It has been confirmed that their points of origin are mostly lunar (from the moon) and/or Martian (from Mars). They may look like regular rocks, but it is living proof that the existence of other life forms may not be so impossible after all.

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A Nova is one event that happens repeatedly in the universe. This phenomena happens when a star comes to an end. As the light and heat capacity of stars wear throughout the years, it suddenly becomes pale white, thus getting the name “white dwarf”, due to the shrinking and dimming light power of the star. As time passes by, it then explodes, causing the star to burn out its remaining energy and become brighter than it ever was.

One example of this is the Supernova of 1054. This happened in China, when astronomers saw a star so bright that it was seen during the day. And since this occurrence was quite astonishing and odd, this event was recorded.

Books also say that a Nova is the smaller version of a supernova, since an event like this happens with a pair of stars, one which is a white dwarf and that of a cooler star. Since materials are being sucked off by the white dwarf, this causes the explosion of the star, though it may not be totally obliterated.

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A telescope is an instrument used to observe objects from afar. The word is derived from Greek words tele and skopein which means “far” and “to see” respectively. Contrary to popular belief, it was not ‘invented' by Galileo. There has been evidence of a refracting telescope that has been in use in the Netherlands during 1608 and its development was credited to spectacle makers Hans Lippershey and Zacharias Janssen, and a third person Jacob Metius. However, it was Galileo who improved on the devices soon after so they can be used for exploring the heavens.

A telescope works by collecting electromagnetic radiation, which on earth-speak means visible light. However, with the development of space technology, there has risen the capability to utilize the full range of the electromagnetic spectrum and use the radio band. The first radio telescope was used in 1937 and there have been subsequent development of telescopes that can work with other wavelengths such as gamma rays.

Photo by: Mike Peel Creative Commons

A telescope has A telescope has three major capabilities – the ability to magnify, the ability to resolve images and create sharp images and the most important being the ability to collect light so it ‘sees' better (which is also the reason why your pupils enlarge when the room is dark or when it's nighttime). The part of a telescope which collects light is the ‘objective'. The objective of a refractor telescope is a glass lens and a reflector telescope uses a (surprise, surprise) mirror.

The first telescopes used to observe the heavens where refractor telescopes and they were subject to problems of chromic aberration or color distortion and spherical aberration among others. It wasn't until 1668 that the first practical reflecting telescope was developed by no other than Sir Isaac Newton with the idea that parabolic mirrors can reduce aberration and more than a hundred years after, achromatic lenses where developed and the rest, as they say, is history.

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The Search for Extra-Terrestrial Intelligence (SETI) is a combined name for those activities related to the continuous search for any intelligent extraterrestrial life in the universe, other than earth. These activities and projects apply various scientific methods to scan the vast space for any forms of electromagnetic transmissions from intelligent civilizations on those distant planets. Early contributors to the SETI projects include the U.S. government, but recent projects are now primarily funded by various private sources.

The continuous search all around the cosmos for that first-ever intelligent transmission is a real challenge, since the general direction of the transmission and the communication methods remains unknown. Because of this, SETI projects have to make all those vital assumptions just to narrow the search grid, given the vastness of space. And with that came the first assumption that intelligent species, who could be of course hundreds, or even million years old well ahead of us could be using technology way beyond our imagination, probably through electromagnetic radiation as their way of communicating.

Various radio experiments have undertaken just for this purpose. They do so with the knowledge that several radio frequencies are well capable of penetrating our atmosphere, which then led to the use of radio telescopes investigating the cosmos using their large radio antennas all the time. Also, our planet emits radio radiation considerably because of our televisions and radio. Their radiations are easily recognizable as artificial. This can make the process of detecting those non-natural radio emissions from anywhere outside the solar system more manageable.

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A nebula or a “newborn star” appears like a cloud of gas and dust. More accurately, a nebula cloud is actually the birthplace of not just one but many stars. Nebulae (the plural of nebula) are mostly made up of hydrogen and other gases, and these determine the nebula’s appearance and, consequently, its classification or kind. There are emission nebulae, reflection nebulae, and even dark nebulae, to mention a few types.

The next phase in a star's life cycle is as a “regular” star––the kind seen normally in the nighttime skies, and of which the sun in our solar system is a good example. Our own sun is comparable to a teen-age star.

Millions of years later, a normal star will become a red giant, and then a red dwarf, and finally a white dwarf or a neutron star. A neutron star is much smaller than it used to be, like a drastically shrunken version of the original, but it is still very hot. The average neutron star is just about 1% the size of our sun, or as big as the earth, but its temperature can be something like 8,000 degrees Celsius. It is also much less bright than a regular star. Eventually, a neutron star cools and then fades. The whole process of a star’s “death” takes billions of years.

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Venus

Actually, the planet Mercury has the same behavior of being visible at dawn and at dusk. However, it can only be observed during a few weeks in a year. Since Venus is much larger and closer to earth, it has earned the title.

Because of its proximity to the sun, Venus is always found on the same side of the sky. If the sun is just setting to the west, the “star” can only be found at the west too. Its sulfuric acid clouds are highly reflective, causing it to glow brightly.

Venus is usually called the earth’s twin in terms of size, composition and gravitational pull. However, the atmosphere of the Evening Star is too hostile for life to exist. The atmospheric pressure on its surface is about 90 times greater than the earth’s. The air is also mostly carbon dioxide.

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Observational astronomy was thus born as a way to acquire more data about the planets, sun and stars.

Basic principles of physics and mathematics were employed as a means to acquire the needed data. Determining a celestial body’s mass, density, size and volume already provides an astronomer enough information as to what this celestial body could be. Aside from this, its degree of temperature and degree of angle from the celestial equator can give an insight as to how hot or cold the celestial body is, and how far it is from Earth respectively.

As more people realized the importance of astronomy, they also realized the need to gain basic understanding of it hence schools began offering courses in Astronomy. Companies that specialized on Astronomy and Space, such as the famous National Aeronautics and Space Administration (NASA) usually require their employees to have at least a degree in Astronomy, Physics or other related courses.

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The word “nebula” comes from Latin which means “cloud.” It is apt, because nebulae (the plural of nebula) look like clouds of gases. Nebulae are made up mostly of hydrogen and helium gases, plus plasma and dust. These clouds are believed to be the birthplace of stars.

There are many kinds of nebulae, often determined by the gases that make them up and how they appear to observers on earth. One type is the diffuse nebula, which has no definite shape and no definite outlines. Another type is the emission nebula, made up of plasma or ionized gas, and emitting multi-colored lights. An example of an emission nebula is the Eagle nebula. Yet another type is a planetary nebula, such as the Cat's Eye Nebula. This is thought to be composed of the shells of “dying” stars called white dwarves.

A very fascinating type of nebula is the dark nebula, an example of which is the Horsehead Nebula. This kind of nebula is extremely dense, with very thick clouds that block out the light behind them and stars in the background. Aside from those mentioned, some famous nebulae are the Crab Nebula or M-1, M-57 which is a Ring Nebula, the Cygnus Loop, and the Orion Nebula. These are fascinating objects in the sky that can be watched through a telescope.

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The lunar month is used by different cultures around the world. In the Middle East, people mark the beginning of this month when a young crescent moon appears after a close pairing of a celestial body with the Sun occurs or maybe about one or a couple of days before. Egyptians determine the beginning of this month when the Moon is no longer visible before sunrise.

A lunar month is equivalent to a synodic month with an approximate length of 29 days, 12 hours, 44 minutes and 3 seconds. There other ways of interpreting this particular month.

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