CometsQuestions and Answers in our Himalayan Task.
Comets
Why does a comet’s tail sometimes precede the comet?
The gas and dust in a comet’s tail are extremely lightweight. The tails are created by solar wind rushing past the orbiting comet and blowing material away from the defrosting coma. When the comet approaches the Sun, the force of the wind pushes the tail out behind the comet. When the comet is moving away from the Sun, the wind still rushes past it, now sending the comet’s tail out in front.
Are
comets likely to collide with Earth?
Cometary orbits are not steady and orderly like planetary orbits. Comets can come from any part of the sky on any trajectory. The chances of a planet getting in the way are pretty good, especially since a planet’s gravity will draw a nearby comet toward it. On June 30, 1908, a comet was reported to have crashed in Russia’s Siberian wildness. (Recent reports have raised a question as to whether it was a comet or an asteroid.) Its nucleus vaporized in the atmosphere, but the tremors from its impact were detected.
Do
comets last forever?
Whenever a comet makes a pass around the Sun, it loses some of its matter. The ices melt and the dust streams off in a tail. Inevitably, the comet will be reduced to a meteor or to celestial confetti, or resemble an asteroid (a burned-out comet). Some comets collide with the Sun or a planet. Others break up under the pressure of gravity into two or more comets. Still others have a parabolic or hyperbolic-no –return-orbit that shoots them out of the solar system, and we don’t know what happens to them.
Why
do comets orbit the Sun?
Comets are probably ejected from the Oort Cloud or Kuiper Belt as a result of a collision. Once disturbed, they are caught by the Sun’s orbit gravity and fly into an orbit around the star. Comets that orbit the sun once every 20 Comets are probably ejected from the Oort Cloud or Kuiper Belt as a result of a collision. Once disturbed, they are caught by the Sun’s orbit gravity and fly into an orbit around the star. Comets that orbit the sun once every 200 years, or less, are called short-period comets, and probably come from the Kuiper Belt or the Oort Cloud. Comets that take longer than 200 years are called long –periods comets, and probably come from the Oort Cloud. Some comets do not have a periodic orbit at all, But swing around the Sun only to go flying off into space forever.
What
happens if earth goes through a comet’s tail?
Earth is more likely to pass through the tail of a comet than to collide with a comet head on. After all, a tail can be a million of times larger than the nucleus. Passing through a tail doesn’t have any great effect – beyond a good meteor shower – since comets’ tails are severely lacking in density. In 1910, however, when Earth went through the tail of Halley’s comet, people spent good money on remedies for the expected consequent illness and disasters.
STARS
What are the stages of
a star’s life?
Star can be said to go through the same stages of life as people: birth, infancy, maturity, old age, and death. As with people stars are not the same. The differences in their lives—their spectral class, life expectancy, and eventual end—depend primarily in their mass, or the amount of matter they have.
When do stars leave the main sequence?
When stars have used up most of the hydrogen in their cores (through thermonuclear fusion), they leave the main sequence and pass into old age. Most stars, the sun included, will turn into red giant or super giants.
How could stars become
black holes?
Black holes were first discussed in1783, but their existence has not been proven beyond a shadow of a doubt. Astronomers theorize that if a large mass were squashed into a tiny space, the resulting power of gravity would attract and devour all nearby matter, even light. It would be black hole. Black holes are not actually holes in space. They are objects.
METEORS
How many meteors can be seen in one night?
Not all meteors come in showers. Under clear, dark skies, you should be able to see five or six meteors a night—if you stay up all night. During an annual shower – or a storm—you can see hundreds a night
When can you see
meteor showers or storms?
Earth passes annually
through commentary orbits, which are littered with leftover
particles. The consequent meteor showers are plentiful and heavy.
The showers known as the preside display up to sixty- eight
meteors an hour at its peak around August 12; the ETA Aquarids,
around May 5, average about ten an hour, up to a maximum of
twenty, and is associated with Halley’s comet. The Leonids,
peaking around November 17, vary from year to year, but are
usually weak. In1866, 1933, and 1966, however, they stormed. In
1966, meteors rained at a peak rate of 60,000to 100,000 per hour,
through the shower lasted only 40 minutes. Another Leonid storm in expected
in 1999.
Are meteor showers dangerous?
Most meteors burn up long before they reach Earth’s surface. Shooting stars, as they are nicknamed, first appear about 70miles (115km) above Earth. They die out by the time they are 40 miles (65km) above Earth.
Will a Meteorite hit Earth Again?
Meteorites hit the earth everyday, but are
so small that only a handful each year is noticed. Chances are
about a million to one that a substantial meteorite will reach
Earth in any given year, but, statistically, it is inevibleta.
Will a meteorite hit earth again?
Meteorites can fall anywhere on Earth. Depending on where they fall and their size, they could cause considerable damage. But this has rarely happened. Most meteorites weight only 2.2 pounds (1kg), and most break into smaller pieces or vaporize on impact. The most destructive meteorite of all time is purely hypothetical: Many scientists believe that a huge meteorite (maybe a comet or an asteroid) struck Earth some 65 million years ago, causing the extinction of dinosaurs.