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Science Our Solar System: A Photo Tour
2011.09.30 06:15
Our Solar System: A Photo Tour of the Planets From "Space.com", Original article by Tom Chao, Date: 25 July 2011 Our Planetary Neighborhood  Credit: NASA Our solar system contains objects ranging in size from the sun, the largest item, to tiny grains of rock in the asteroid belt. Let's take a tour of our cosmic neighborhood in pictures. The Sun The sun, the star at the center of our solar system, controls everything within its mighty gravity field, commanding planets to orbit or pulling comets straight into it. It holds 99.8 percent of the solar system's mass, and measures roughly 109 times the diameter of the Earth. The visible part of the sun reaches a temperature of roughly 10,000 degrees F (5,500 degrees C), while temperatures in the core exceed 27 million degrees F (15 million degrees C), driven by nuclear reactions. It's plenty dangerous! Sun Plasma Flickers Mercury How did it form? The leading theory suggests that a body smashed into Earth approximately 4.5 billion years ago, and the debris from both Earth and the impactor accumulated to form our natural satellite. Let's go back and visit it again!  Credit: ESA/NASA The Earth and the moon as seen on Jan. 15, 2011, from the International Space Station by astronaut Paolo Nespoli.  Credit: The Viking Project/NASA Mars, the mysterious red ball 141,637,725 miles (227,943,824 km) from the sun, is a desolate rock that may have once held rivers of flowing water. The Red Planet possesses stark landscapes featuring both the highest mountain and the deepest, longest valley in the solar system. Its radius is about 2,106.1 miles (3,389.5 km). Mars is much colder than Earth, largely due to its greater distance from the sun. The average temperature hovers around a frosty minus 80 degrees F (minus 60 degrees C). Channels, valleys, and gullies cut into the entire surface of Mars, and suggest that liquid water might have flowed across the planet's surface. Let's go there next!  Credit: NASA NASA's Viking probes were the first ever to successfully set footpad on Mars in a powered landing. The Viking 1 lander set down in July 1976 and didn't go silent until November 1982. Viking 2 landed in September 1976 and kept working until April 1980. Asteroids Credit: ESA Full Story After Mars comes the asteroid belt, a girdle of rocky objects between the orbits of Mars and Jupiter, about 186 million to 370 million miles (300 million to 600 million kilometers) from the sun. Asteroids are small, airless rocky objects revolving around the sun, but are too small to be planets. They are also known as planetoids or minor planets. Most asteroids lie in the asteroid belts, but there are others across the solar system. Asteroids represent the leftovers from the formation of our solar system about 4.6 billion years ago. They are dirty bastards that could rip your spacecraft to shreds in an instant. If you had a spacecraft. You wish you had a spacecraft.  Credit: Emily Lakdawalla/Ted Stryk Here's a look at the handful of asteroids that have been visited by robot probes from Earth. Only a few near-Earth objects would fit NASA's proposed guidelines for a manned mission to an asteroid. Jupiter Jupiter is the most massive planet in our solar system, more than twice as massive as all the other planets combined. Strong east-west winds in the planet's upper atmosphere create the dark belts and light zones of Jupiter's variegated appearance. The enormous planet lies 483,638,564 miles (778,340,821 km) from the sun, and has a radius of about 43,440.7 miles (69,911 km). Jupiter also possesses four large moons and many smaller moons. Jupiter has a gaseous composition, referred to as a "gas giant." Some astronomers believe Jupiter may have once possessed the capability to coalesce into a binary star companion of our sun. If only Jupiter had any real ambition. Lazy gas giant. Jupiter's Moons: Family Portrait NASA/Johns Hopkins University Applied Physics Lab/Southwest Research Institute This montage shows the best views of Jupiter's four large and diverse "Galilean" satellites as seen by the Long Range Reconnaissance Imager (LORRI) on the New Horizons spacecraft during its flyby of Jupiter in late February 2007. The four moons are, from left to right: Io, Europa, Ganymede and Callisto. The images have been scaled to represent the true relative sizes of the four moons and are arranged in their order from Jupiter. Saturn Credit: NASA/JPL/Space Science Institute Saturn, another gas giant like Jupiter, spins faster than any other planet, and is the furthest planet that can be seen by the naked human eye, 886,489,415 miles (1,426,666,422 km) from the sun. Saturn, with a radius of about 36,183.7 miles (58,232 km), possesses moons but it is better known for its rings, composed of tiny bits of ice and rock, believed to be debris left over from comets, asteroids or shattered moons. Does having rings make you special, Saturn? No, because Jupiter, Uranus and Neptune also possess rings. But Saturn, yours are definitely the most stunning. Fabulous Saturn: Rings, Baubles and Spiky Spokes Credit: null Speaking of Saturn's rings: From trillions of icy ring dust particles, finer than baker's flour, to more than 60 moons, each a unique world, the kingdom of Saturn is rich with mystery. Uranus Credit: Lawrence Sromovsky, UW-Madison Uranus consists of a bunch of frozen water, methane, and ammonia, with a blue-green color caused by hydrogen and helium in its atmosphere. Its crazy axis of rotation tilts so far over that it is almost pointing at the sun. Just remember that Uranus is spinning on its side, like a top that's fallen over. This planet is 1,783,744,300 miles (2,870,658,186 km) from the sun, and has a radius of about 15,759.2 miles (25,362 km). Uranus, though visible to the naked eye, was long considered a star, until British astronomer William Herschel discovered Uranus accidentally on March 13, 1781. And let's have no more terrible puns on the name of "Uranus." The Weird Tilt of Uranus Credit: NASA and Erich Karkoschka, U. of Arizona Uranus' tilt essentially has the planet orbiting the Sun on its side, the axis of its spin is nearly pointing at the Sun. Neptune Credit: NASA Neptune shines a deep blue color. Its color comes from an unidentified compound in its atmosphere composed of mainly hydrogen and helium. This planet orbits 2,795,173,960 miles (4,498,396,441 km) from the sun, and has a radius of about 15,299.4 miles (24,622 km). Among the planets, Neptune is known for its crazy-fast winds, which can blow up to 1,500 miles per hour (2,400 kilometers per hour), the fastest detected yet in the solar system. Also, Neptune was discovered only after astronomers noticed irregular behavior in the orbit of Uranus. And no, you should never use the words "irregular" and "Uranus" in the same sentence. The Winds of Neptune Credit: NASA/JPL Neptune's winds travel at more than 1,500 mph, and are the fastest planetary winds in the solar system. Comets Credit: NASA/JPL-Caltech Comets are cold, dirty aggregations of rock and ice that release gas or dust. The solid core of a comet consists mostly of ice and dust coated with dark organic material, with the ice composed mainly of frozen water. When heated by the sun, the comet's surface ice turns into a gas, forming a cloud called a coma which stretches into a dust tail and an ion tail. Comets zoom in crazily elliptical orbits around the sun. They can take decades to make one orbit, such as Halley's Comet, which returns once every 76 years. Many have much longer orbital durations, over 200 years. When comets travel close enough to the Earth, their long tails can trigger meteor showers. Sometimes comets crash into the sun or into planets like Jupiter, and sometimes they only appear once and never return. Comet Hale-Bopp Credit: John Gleason John Gleason captured this amazing shot of the comet Hale-Bopp in March 1997. Kuiper Belt — Trans-Neptunian Region Credit: NASA/JPL-Caltech/T. Pyle (SSC) Out past the orbit of Neptune and the other planets, the solar system gets mighty cold and dark. Really. The area known as the Kuiper belt holds hundreds of thousands of icy bodies larger than 60 miles (100 km) wide, as well as an estimated trillion or more comets. Smallest Object in Outer Solar System Spotted Credit: NASA, ESA, and G. Bacon (STScI) This is an artist's impression of a small Kuiper Belt Object (KBO) occulting a star. NASA's Hubble Space Telescope recorded this brief event and allowed astronomers to determine that the KBO was only one-half of a mile across, setting a new record for the smallest object ever seen in the Kuiper Belt. Pluto Credit: Hubble Pluto, the dwarf planet, has gone through some changes. Clyde Tombaugh discovered Pluto in 1930, based on predictions from Percival Lowell and other astronomers. Pluto is only 1,400 miles (2,300 kilometers) wide and is about 3.6 billion miles from Earth. It has four moons, the latest of which was announced in July 2011. Pluto used to be classified as a full-fledged planet until the International Astronomical Union (IAU) downgraded it a dwarf planet in 2006 because its small size. Oh, no, they di'int! Oh, yes, they did! Pluto has serious planet envy now. Also, Pluto's orbit tilts 17 degrees from the ecliptic plane. Pluto Unveiled Credit: NASA, ESA, and M. Buie (Southwest Research Institute) This is the most detailed view to date of the entire surface of the dwarf planet Pluto, as constructed from multiple NASA Hubble Space Telescope photographs taken from 2002 to 2003, before the telescope’s latest overhaul. The center disk (180 degrees) has a mysterious bright spot that is unusually rich in carbon monoxide frost. The image was released in February 2010. Dwarf Planets Credit: IAU/M. Kornmesser Dwarf planets belong to a newer classification in the solar system naming scheme. The International Astronomical Union defines a dwarf planet as "an object in orbit around the Sun that is large enough (massive) to have its own gravity pull itself into a round (or nearly round) shape. Generally, a dwarf planet is smaller than Mercury. A dwarf planet may also orbit in a zone that has many other objects in it. For example, an orbit within the asteroid belt is in a zone with lots of other objects." Got that? Other objects are okay! The Weirdest Object in the Solar System? Credit: Mike Brown/Caltech Haumea is one of the strangest known objects in the solar system. It is as big across as Pluto but shaped like a cigar or perhaps an American football. These two images show the two extremes of its appearance as it spins. Oort Cloud Credit: NASA/JPL-Caltech/R. Hurt But wait: there's more! Beyond the Kuiper belt lies the Oort cloud, which theoretically extends from 5,000 to 100,000 times the distance of Earth to the sun, and is home to up to two trillion icy bodies. An object called Sedna, about three-fourths the size of Pluto, might be the first dwarf planet discovered in the Oort cloud. Heliosphere Credit: NASA At last we arrive at the very edge of the solar system where the heliosphere lies, a teardrop-shaped region of space containing electrically charged particles given off by the sun. Many astronomers think that the limit of the heliosphere, known as the heliopause, lies about 9 billion miles (15 billion kilometers) from the sun. And that completes our tour of the solar system. Welcome to interstellar space!
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![Skywatcher Jimmy Eubanks in Boiling Springs, South Carolina caught these photos of Jupiter and Uranus on Sept. 20, 2010 when Jupiter made its closest approach to Earth since 1963. Uranus [insert] was visible through telescopes near Jupiter.](http://i.space.com/images/i/5968/i02/jupiter-uranus-eubanks-photo-100923-02.jpg)
Comment 3
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운영자
2011.09.30 06:18
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이한중*65
2011.09.30 14:07
Why Earth is the Garden of Eden
According to Brownlee and Ward, professors at the University of Washington, Seattle,
some of the key factors in making Earth the Garden of Eden are:
1. The correct distance from the Sun, which moderates temperatures.
2. The right mass of the Sun, which provides stable planetary orbits in which
the other planets in the solar system do not create orbital chaos.
3. The right planetary mass, which allows Earth to retain its atmosphere and oceans.
4. Jupiter as a neighbor at the correct distance; the larger planet acts as buffer,
clearing out comets and asteroids that might otherwise strike Earth with cataclysmic results.
5. Plate tectonics that build up landmass and enhances biodiversity.
6. Oceans in the right proportions.
7. A large Moon at the correct distance to stabilize Earth's tilt.
8. The correct tilt of Earth on its axis, which moderates seasons.
9. Few giant catastrophic impacts in Earth's history.
10. The right amount of carbon; sufficient for life but not enough to create
a runaway Greenhouse Effect, like on Venus.
11. Biological evolution--the pathway to complex plants and animals.
12. The correct position of the solar system in the galaxy--not in the center,
where it would be subject to much greater radiation. -
운영자
2011.10.01 15:40
I guess the earth was there first, and then the God (or the evolution) created us to fit it.
Somehow, I think there are living things on all those planets,
even though they may be conceptionally entirely different organisms than the earth-bound life.
In the deep sea of the earth, there are living things that don't depend on oxygen at all.
Living energy can be obtained from almost any chemical.
I am also sure that there is a plenty of intelligent beings in the universe
but none of them (including us) can overcome the barrier of the "insurmountable distance
and time" of the universe to get together.The humanity will be riding the earth along for a while for about 5 billion years or so
and then sun gradually exhausts its nuclear energy and turns into a "Red Giant."
It will expand into a big red star engulfing the earth and up to Mars.
In that process, we will be all toasted into ashes and gases.
Only way to survive is that we find a way of escaping to another "star and planet" system.
However, there's no star system nearby (to travel and reach within our life span)
that is compatible with our disposition.
(Hey, but we can be traveling while changing generations on the space ship. Why not?
Alternatively, we might become a group of eternal space gypsies.)
In the meantime the Red Giant will exhaust its energy and collapse into a "White Dwarf."
(The sun will not become a Supernova because it's not heavy enough.
It has to be at least 1.4 - two times heavier than it is to develop into a supernova.
Too bad... I am really very sorry... There will be no final glorious thundering fireworks !!)Will we become smart enough to watch the sun turning into a White Dwarf
from a nearby star system as new space immigrants? ㅎ, ㅎ, ㅎ.
The answer is beyond the level of our current (and maybe even our future) intelligence.
So, there's no answer from us.
When there's no answer, don't worry... the divine God will take care of it.In my faith, the above is what the God is supposed to manage.
He's not there or isn't dumb enough to listen to our pitiful selfish wishes,
and to give us some trivial contradictory and meaningless blessings.
I wish if I can take these pictures of these planets as I am flying by.
How deep, wide, empty, and mysterious is the universe outside of our earth !!
How miserably are we stuck on the tiny crowded planet Earth !!