MMM! Spaghetti ;D
In astrophysics, spaghettification (sometimes referred to as the noodle effect[1]) is the vertical stretching and horizontal compression of objects into long thin shapes (rather like spaghetti) in a very strong gravitational field, and is caused by extreme tidal forces. In the most extreme cases, near black holes, the stretching is so powerful that no object can withstand it, no matter how strong its components. Within a small region the horizontal compression balances the vertical stretching so that small objects being spaghettified experience no net change in volume.
Ditto
Comets
I have always been fascinated by comets since a very young age when me and my
family happened to see the comet Hale-Bopp one night as we were out on the deck
looking up at the sky.
We had heard about it being visible on the news, and as it got dark, we stepped
outside and witnessed the amazing sight of the comet moving slowly through the
sky that was right in front of our vantage point.
I didn’t completely understand what comets were at the time as I was just 4 years
old, but since then, I had always wondered about what comets were and where
they come from. Which is why I decided to do my paper on comets, so I could find
out more about these strange space objects and hopefully find out something
surprising.
Comets (with the name coming from the Latin word “coma” which means “hair”,
which refers to a comets tail.) must have surely have been observed in prehistoric
times, but the oldest written records of them are from about 2,000 years ago as
stated in the Field Guide To The Night Sky by the National Audubon Society, which
gives the example of comets shown in recordings in ancient Egyptian hieroglyphic
texts.
In many of these older observations, comets are confused with such atmospheric
phenomena as auroras and noctilucent clouds (thin, high altitude clouds
illuminated by the sun after it has set below the horizon.)
Often, comets were believed to have been the finger of a god, or a sword pointed at
the earth.
The Romans considered comets evil omens, or signs of some disaster or hardship
that may be coming in the near future.
It wasn’t until 1577 that comets were recognized as as members of the solar
system.
Comets are composed of rock, dust, ice and amino acids and can range in size
from around 100 meters to more than 40 kilometers across with most forming in the
trans-neptunian region of the solar system.
A comet is made up of 3 major components: The Nucleus, which is composed of
rock, dust, ice, and frozen gasses such as carbon monoxide, carbon dioxide,
methane, and ammonia. The Coma, which is a diffused cloud of gas and dust that
surrounds the nucleus.
And a Tail, which is also made up of gas and dust that becomes illuminated by the
sun.
One interesting feature of a comet is that it actually has 2 tails.
One tail is the debris tail which streams dust and gas from the atmosphere around
the comet, and the second tail is formed by the suns solar winds causing the tail to
point away from the sun.
Both the tail and coma cannot be seen from earth until the comet passes through
the inner solar system and reflects sunlight.
It is possible for a comet to lose its tail. If the ion tail loading is sufficient, then the
magnetic field lines can be squeezed together to the point where magnetic
reconnection occurs. This leads to a “tail disconnection event” which was observed
in April of 2007 on comet Encke.
An interesting result that comes from the tail of a comet, are meteor showers.
A comet will leave a trail of solid debris as it travels through the solar system, and if
a comet’s path crosses the earths path, then it is very likely that we will see a
meteor shower here on earth as a result of the debris burning up in our own
atmosphere.
Comets are categorized in 3 main divisions based on their elliptical orbits that bring
them close to the sun for part of their orbit, and further out into the solar system for
the rest of its travel.
The 3 categories are Short period, long period, and single apparition comets.
Short period comets are comets that have an orbital period around the sun of less
than 200 years. One such comet that is quite well known is “Haley’s comet.”
Long period comets are comets that have an orbital period around the sun of
greater than 200 years. An example of this would be “comet West”
Singe apparition comets are comets that never return to our solar system. An
example of this particular classification of comet, would be C/1980 E1.
A Comet has an elliptical orbit that gets close to the sun at one point of its orbit.
As the comet approaches and rounds the Sun, its weak internal structure
undergoes a great deal of stress. both from gravity and from heat. Frequently,
comets do not make it around the Sun, as stated in “Cosmos” by Giles Sparrow.
Some comets that get close to the sun may evaporate completely during their
passage, while others may actually make a trajectory that leads them right into the
sun.
Some other comets disintegrate into fragments that continue along their original
orbit as a chain of mini-comets.
When a comet “survives” after passing close to the sun, it travels far into the outer
solar system where it may return some time in the future. Possibly in a matter of
decades (short period comet), or in thousands of years (long period comets).
As I had mentioned earlier, I was lucky enough to see the comet Hale-Bopp as it
traveled through the sky.
Hale-Bopp (which was discovered in 1995 by astronomers Alan Hale and Thomas
Bopp) is a famous comet as it was able to be seen by the naked eye for a total of
18 months.
The comet first became visible (to the naked eye) in May of 1996. It gradually grew
brighter throughout the months and shone brightest on April 1st of 1997 where it
could be seen even before the sky got completely dark.
One very interesting feature of Hale-Bopp is that it actually has a third type of tail as
opposed to the common two of most other comets.
It was found that Comet Hale-Bopp had a sodium tail which was only visible using
specific instruments.
The source of the sodium appeared to be the inner coma which could be caused
by collisions between dust grains surrounding the nucleus, and sputtering of
sodium from dust grains by UV light.
I feel very privileged to have been able to see this comet in person in the night sky
as it is an occurrence that won’t happen again until the year 4385 which will be
long after I am gone.
As amazing and popular as Comet Hale-Bopp is, probably the most famous and
well known comet that has passed by the earth is “Halley’s Comet.”
Halley’s Comet is a short period comet that is visible from earth every 75 years.
Early documentation of the comet have been made since at least 240 BCE, with
records being shown from the Chinese, Babylonian, and medieval European
chroniclers, but these were not classified as reappearances of the same comet.
The comets reappearance was first determined in 1705 by Edmond Halley (who is
the individual who the comet was named after.) and it was proven to be an
accurate prediction.
Halley’s Comet was last seen in 1986 and will appear again in what astronomers
predict will be in 2061.
As I had mentioned earlier, some comets can be destroyed as they pass or collide
with the sun.
Comets can also be destroyed by colliding with planets as we saw in July of 1994
when comet “Shoemaker-Levy 9” broke up into multiple pieces and collided with
Jupiter.
The collision was quite large and left brown impact spots on Jupiter’s southern
hemisphere.
Comets are something that has fascinated people for thousands of years. From the
earliest civilizations to the modern day, comets are a part of stories, movies, tv
shows, and other realms of popular culture.
Hopefully more people can take the time to research and understand just what
these space objects are, and what makes them so unique in comparison to the
other objects that are in our solar system and beyond.
Its been an eye opening experience to research and learn more about these
objects for myself and hopefully, I will be privileged enough to see another one in
person someday.
Just read the whole thing, I am proud of myself.
gud.
u lernd.