The Planets Information Brochure

The Planets
Andrew Calin Paladie
Erin Lauen
March 10, 2011
Mercury (Science)
The scorching-hot Mercury is only a
little a bit larger than the Earth’s moon. A lot
like the moon, it has a very little atmosphere
to stop impacts, which makes it the reason
why thousands of craters are covering up
Mercury. During the daytime, temperatures
increase quickly because of the sun. But,
during the night, Mercury’s temperature
decreases immediately below zero. Mercury’s
egg shaped orbit takes it around the sun
every 88 days. Mercury is named for the
swiftest of the ancient Roman gods. Mercury,
the god of commerce, is the Roman
counterpart to the great Greek god Hermes.
The messenger of the gods.
The first ever spacecraft to visit
Mercury was Mariner 10. In 1991,
astronomers on Earth using radar
observations showed that Mercury may have
watered ice at Mercury’s north and south
poles. Comets or meteorites might have
brought ice to these parts of regions on
Mercury, or maybe water vapor may have
out-gassed from the interior and frozen out
at the poles.
Venus (Science)
Venus is a little dim world of intense
heat and volcanic activity. Similarly the same
structure and size as Earth, Venus’ think and
toxic atmosphere keeps heat in a runaway
called “greenhouse effect”. The burning hot
world, has huge temperatures hot enough to
burn/melt lead. Little glimpses below the
clouds reveal big amounts of volcanoes and
deformed mountains. Venus spins slowly in
the opposite direction of most planets.
There actually hasn’t been much
history of anybody ‘landing’ on Venus.
Because of its burning-hot temperature, they
have to take radar images by NASA’s
Magellan mission to Venus during the early
1990s. The Galileo spacecraft used infrared
mapping to get a good view on the mid-level
cloud structure as it had passed by Venus in
1990 on its way to Jupiter.
Earth (Science)
Earth is simply an ocean/water
planet. Our planet Earth’s water and life
makes Earth very unique in the Solar
System. Other planets, such as: Jupiter,
Uranus, Mercury, and a couple of moons,
have ice, atmospheres, seasons and also
weather. Though, only Earth does the whole
complicated mix together in a way that
encourages a lot of life.
There has been actually five missions
deployed to study our planet Earth. So, there
has been a lot of history for our planet Earth.
One of the missions was Galileo. Galileo
used Earth's gravity to help it build up
enough speed to hurl itself toward Jupiter.
But the Earth flyby provided a chance to use
the spacecraft's instruments to study Earth
from a unique perspective. The
accomplishment was: the Galileo spacecraft
found evidence of life on Earth. Not a
surprising discovery, but the use of
instruments to detect traces of life in a
planet's atmosphere will be useful as future
space probes continue to seek evidence of
life beyond Earth.
Earth (Science) Part 2
Another mission was the Bumper Project. Bumper rockets were the first two-stage rockets
-- a German V-2 missile coupled with an American-made WAC Corporal. They were designed to test
high altitude rocket systems and study Earth's upper atmosphere. The accomplishment of it:
Bumper rockets were the first human-made objects to cross the boundary into outer space,
although they did not orbit the Earth like Sputnik 1 (the first true spacecraft). The rocket's upper
stages were able to reach then-record altitudes of up to 399 kilometers (248 miles), higher than
even modern space shuttles fly. The rockets' small science payloads also sent back information on
air temperatures and cosmic ray impacts.
Also another mission was the Deep Impact-EPOXI. Deep Impact's primary mission was to
deliver a special impactor spacecraft into the path of comet Tempel 1. After its successful impact
mission, Deep impact was used to view the Earth from a distant alien perspective to aid in the
search for Earth-like worlds in other solar systems and its accomplishment was: Making a video of
Earth from so far away helps the search for other life-bearing planets in the Universe by giving
insights into how a distant, Earth-like alien world would appear to us. For example, Sun glints off
Earth's oceans could guide scientists to spot alien oceans (and potentially habitable alien worlds).
Out of all of those five missions—I have listed 3 of them for you.
Earth is known to only have one moon. It isn’t named anything. Really, it’s just called the
Moon. The only moon Earth has. The only thing in the solar system that has the greatest
gravitational pull. Also, known to have huge craters just like Mercury. So, to this day, Earth is
known to have only one moon. Named—the Moon.
Mars (Science)
Mars looks like a burning hot planet
in this picture (right). But, actually it’s a cold
desert world. It is half the diameter of Earth
and has the same amount of dry land. Like
Earth, Mars has seasons, polar ice caps,
volcanoes, canyons and weather, but its
atmosphere is too thin for liquid water to
exist for long on the surface. There are signs
of ancient floods on Mars, but evidence for
water now exists mainly in icy soil and thin
There has been 4 missions set to
search the planet Mars, now for only one
reason. To search if there is life. One of the 4
missions was the Mars Exploration Rover:
Spirit/Opportunity. Its Spirit and its twin
Opportunity were designed to study the
history of climate and water at sites on Mars
where conditions may once have been
favorable to life. Each rover is equipped with
a suite of science instruments to read the
geologic record at each site, to investigate
what role water played there and to
determine how suitable the conditions would
have been for life.
It’s accomplishment had: Both rovers far exceeded their design specifications and returned science results that transformed
our understanding of Mars.
Mars (Science) Part 2
Asaph Hall was about to give up his frustrating search for a Martian moon one August night
in 1877, but his wife Angelina urged him on. He discovered Deimos the next night, and Phobos six
nights after that.
Ninety-four years later, NASA's Mariner 9 spacecraft got a much better look at the two
moons from its orbit around Mars. The dominant feature on Phobos, it found, was a crater 10 km (6
miles) wide -- nearly half the width of the moon itself. It was given Angelina's maiden name: Stickney.
Hall named the moons for the mythological sons of Ares, the Greek counterpart of the Roman god,
Mars. Phobos means fear or panic (think "phobia"), and Deimos means flight (as in running away after
an overwhelming defeat). Fitting names for the sons of a war god.
Mars' moons are among the smallest in the solar system. Phobos is a bit larger than
Deimos, and orbits only 6,000 km (3,700 miles) above the Martian surface. No known moon orbits
closer to its planet. It whips around Mars three times a day, while the more distant Deimos takes 30
hours for each orbit. Phobos is gradually spiraling inward, drawing about 1.8 m closer to the planet each
century. Within 50 million years, it will either crash into Mars or break up and form a ring around the
To someone standing on the Mars-facing side of Phobos, Mars would take up a large part of
the sky. And people may one day do just that. Scientists have discussed the possibility of using one of
the Martian moons as a base from which astronauts could observe the Red Planet and launch robots to
its surface, while shielded by miles of rock from cosmic rays and solar radiation for nearly two-thirds of
every orbit.
Jupiter (Science)
Understanding Jupiter’s intense
magnetic field, swirling atmosphere and
diverse moons will reveal much about how
planets form and interact.
Jupiter, the most massive planet in
our solar system; with dozens of moons and
an enormous magnetic field, forms a kind of
miniature solar system. Although, Jupiter
does resemble a star in composition, it did
not grow big enough to ignite. Jupiter’s
swirling cloud stripes (as shown in the
picture on the right) are emphasized by
massive storms such as the Great Red Spot,
which has erupted for hundreds of years.
In the past, there have been 8
missions so far, sent to study Jupiter. The
first mission was the Pioneer 10. The goal
of the Pioneer 10 was to launch the first
spacecraft to Jupiter, and fly by it, while
surviving the intense radiation that
surrounds the giant outer planet and then on
a trajectory that would take it out of the
Solar System.
It’s accomplishment made the
spacecraft become the first to fly
beyond Mars' orbit, through the
asteroid belt, and close to Jupiter,
blazing a trail for the two Voyager
spacecraft that were to follow and
conduct more in-depth surveys. Long
before and after flying by Jupiter,
Pioneer 10 transmitted data on the
magnetic fields, energetic particle
radiation and dust populations in
interplanetary space. As it passed
through the Jupiter system, it
transmitted hundreds of photos of the
planet and its moons, along with
measurements of the Jovian
Jupiter (Science) Part 2
There was another mission, called the
Pioneer 11, but let’s skip to the 3rd mission.
The Voyager 1 and 2. Both of these
missions were designed to take advantage of
a rare planetary alignment to explore the
outer solar system. Voyager 1 targeted
Jupiter and Saturn before continuing on to
chart the far edges of our solar system.
It’s accomplishment was that during
the Jupiter leg of its journey, Voyager 1 was
to explore the giant planet, its
magnetosphere and moons in greater detail
than the Pioneer spacecraft that preceded it.
Voyager 1 was not only to study Jupiter, but
to use it as a springboard to Saturn, using
the gravity-assist technique.
Voyager 1 succeeded on all counts,
with the single exception of experiments
using its photo-polarimeter, which failed to
operate. Jupiter's atmosphere was found to
be more active than during the visits of
Pioneer 10 and 11, sparking a rethinking of
the earlier atmospheric models which could
not explain the new features.
Fast Facts
Galileo was launched from the Space
Shuttle Atlantis. The spacecraft traveled more
than 4.6 billion km (about 2.8 billion miles) during
its 14-year mission. Galileo was named in honor of
Galileo Galilei (above), who discovered the largest
moons of Jupiter in 1610. The spacecraft was
named in honor of Galileo Galilei (right), the 17th
Century Italian astronomer who proved planets
orbit our Sun. The spacecraft was the first to orbit
a gas giant planet.
Galileo plunged into Jupiter's crushing
atmosphere on Sept. 21, 2003. The spacecraft
was deliberately destroyed to protect one of its
own discoveries - a possible ocean beneath the icy
crust of the moon Europa.
Jupiter (Science) Part 3
Like the famed astronomer for which it was named, the Galileo spacecraft logged quite a
few firsts during its 14-year mission to Jupiter. Among its discoveries: an intense radiation belt
above Jupiter's cloud tops, helium in about the same concentration as the Sun, extensive and rapid
resurfacing of the moon Io because of volcanism, and evidence for liquid water oceans under the
moon Europa's icy surface.
The rest of the missions we’re called the Ulysses, the Cassini, and the New Horizons!
How wonderful it is to know most of these mission’s accomplishments and goals so you could get a
better recap of them.
The planet Jupiter's four largest moons are called the Galilean satellites, after Italian
astronomer Galileo Galilei, who observed them in 1610. The German astronomer Simon Marius
claimed to have seen the moons around the same time, but he did not publish his observations and
so Galileo is given the credit for their discovery. These large moons, named Io, Europa,
Ganymede, Callisto are each distinctive worlds. There are still much more moons in Jupiter.
Nearly over 45 moons!
Saturn (Science)
Saturn is the sixth planet from the sun and the
second largest planet in our Solar System! Saturn is named
after the Roman god Saturn, assimilated to the Greek
Cronus, the Babylonian Ninurta and the Hindu Shani.
Saturn’s astronomical symbol (♄) represents the Roman
god’s sickle.
Saturn, along with Jupiter, Uranus and Neptune,
is classified as a gas giant. Together, these four planets are
sometimes referred to as the Jovian, meaning "Jupiter-like",
planets. Saturn has an average radius about 9 times larger
than the Earth's. While only 1/8 the average density of
Earth, due to its larger volume, Saturn's mass is just over
95 times greater than Earth's.
Saturn has nine rings, consisting
mostly of ice particles with a smaller
amount of rocky debris and dust.
Sixty-two known moons orbit the
planet; fifty-three are officially
named. This is not counting
hundreds of “moonlets" within the
rings. Titan, Saturn's largest and the
Solar System's second largest moon
(after Jupiter's Ganymede), is larger
than the planet Mercury and is the
only moon in the Solar System to
possess a significant atmosphere.
Because of Saturn's large mass and
resulting gravitation, the conditions produced on Saturn are
extreme if compared to Earth. The interior of Saturn is
probably composed of a core of iron, nickel, silicon and
oxygen compounds, surrounded by a deep layer of metallic
hydrogen, an intermediate layer of liquid.
Hydrogen and liquid helium and finally, an outer
gaseous layer. Electrical current within the metallichydrogen layer is thought to give rise to Saturn's
planetary magnetic field, which is slightly weaker than
Earth's magnetic field and approximately one-twentieth the
strength of the field around Jupiter. The outer atmosphere is
generally bland in appearance, although long-lived features
can appear. Wind speeds on Saturn can reach 1,800 km/h,
significantly faster than those on Jupiter.
Saturn (Science) Part 2
Saturn’s very first mission, in
September 1979, was the Pioneer 11. It flew
within 20,000 km of the planet's cloud tops.
Low resolution images were acquired of the
planet and a few of its moons; the resolution
of the images was not good enough to discern
surface features. One of the accomplishments
was that the spacecraft also studied the rings;
among the discoveries were the thin F-ring
and the fact that dark gaps in the rings are
bright when viewed towards the Sun, in other
words, they are not empty of material.
Pioneer 11 also measured the temperature of
Titan, as an accomplishment. The Pioneer
images of Saturn were significantly dimmer as
the planet and its moons only receive 14.90
W/m^2 (Solar Irradiance) where Jupiter gets
around 400 W/m^2. Camera technology would
be improved in subsequent missions to the
The next mission to Saturn was the
Voyager 1, which occurred in November 1980. It
sent back the first high-resolution images of the
planet, its rings and satellites, one of it’s biggest
accomplishments. Surface features of various moons
were seen for the first time. Voyager 1 performed a
close flyby of Titan, greatly increasing our knowledge
of the atmosphere of the moon. It also proved that
Titan's atmosphere is impenetrable in visible
wavelengths; so, no surface details were seen.
Another accomplishment was that the probes
discovered and confirmed several new satellites orbiting
near or within the planet's rings. They also discovered the
small Maxwell Gaps (a gap within the C Ring) and
Keeler gap (a 42 km wide gap in the A Ring).
Saturn (Science) Part 3
Saturn, the sixth planet from the sun, is home to a vast array of intriguing and unique worlds.
From the cloud-shrouded surface of Titan to crater-riddled Phoebe, each of Saturn's moons tells another
piece of the story surrounding the Saturn system. Christian Huygens discovered the first known moon of
Saturn. The year was 1655 and the moon was Titan. Giovanni Domenico Cassini made the next four
discoveries: Iapetus (1671), Rhea (1672), Dione (1684), and Tethys (1684). Mimas and Enceladus were
both discovered by William Herschel in 1789. The next two discoveries came at intervals of 50 or more
years -- Hyperion (1848) and Phoebe (1898). As telescopic resolving power increased through the 19th
century, Saturn's family of known moons grew. In 1966 Epimetheus and Janus were discovered. By the
time Cassini-Huygens was launched in 1997, Saturn's moon count had reached 18. The number of known
moons soon increased with high-resolution imaging techniques used on ground-based telescopes. The
Cassini mission has discovered several more moons since its arrival at Saturn.
Here's a sampling of some of the unique aspects of the moons:
- Titan is so large that it affects the orbits of other near-by moons. At 5,150 km (3,200 miles) across, it
is the second largest moon in the solar system. Titan hides its surface with a thick nitrogen-rich
atmosphere. Titan's atmosphere is similar to the Earth's atmosphere of long ago, before biology took hold
on our home planet. Titan's atmosphere is approximately 95% nitrogen with traces of methane. While the
Earth's atmosphere extends about 60 km (37 miles) into space, Titan's extends nearly 600 km (ten times
that of the Earth's atmosphere) into space.
- Iapetus has one side as bright as snow and one side as dark as black velvet, with a huge ridge running
around most of its dark-side equator.
- Phoebe orbits the planet in a direction opposite that of Saturn's larger moons, as do several of the
more recently discovered moons.
Uranus (Science)
Uranus spins on an axis that often points directly at the
sun. This odd calibration is thought to be the result of an impact
with some other body, possible a planet-size object, early in its
history. It’s bright blue-green color comes from methane gas in its
climate. Uranus has eleven known rings. These dark circles are
built of fine dust as well as large particles. The planet’s odd rotation
axis means the rings appear face-on from Earth.
Because of its peculiar tilt, the poles of Uranus receive
more energy input from the sun than he equatorial regions. When
Voyager 2 passed Uranus in 1986, the planet’s south pole was
pointed almost directly at the sun.
The first and ONLY mission to set
off and find Uranus was the Voyager 2. The
Voyager 2s main goal was to go and discover
new things from Saturn and Jupiter. After
making a string of discoveries there -- such
as active volcanoes on Jupiter's moon Io and
intricacies of Saturn's rings -- the mission
was extended. Voyager 2 went on to explore
Uranus and Neptune, and is still the only
spacecraft to have visited those outer
planets. The adventurers' current mission,
the Voyager Interstellar Mission (VIM), will
explore the outermost edge of the Sun's
domain. And beyond.
Like Venus, Uranus rotates east to west. Uranus'
rotation axis is tilted almost parallel to its orbital plane, so Uranus
appears to be rotating on its side. This situation may be the result
of a collision with a planet-sized body early in the planet's history,
which apparently radically changed Uranus' rotation. Because of
Uranus' unusual orientation, the planet experiences extreme
variations in sunlight during each 20-year-long season.
Uranus reached equinox in December 2007, when it
was fully illuminated as the sun passed over the planet's equator.
By 2028, the north pole will point directly at the sun, a reversal of
the situation when Voyager flew by. Equinox also brings ring-plane
crossing, when Uranus' rings appear to move more and more edgeon as seen from Earth.
Uranus (Science) Part 2
Uranus is known to have exactly 27 moons.
While most of the satellites orbiting other planets take their names from Greek mythology,
Uranus' moons are unique in being named for Shakespearean characters, along with a couple of the
moons being named for characters from the works of Alexander Pope. Oberon and Titania are the largest
Uranian moons, and were first to be discovered -- by William Herschel in 1787. William Lassell, who had
been first to see a moon orbiting Neptune, discovered the next two, Ariel and Umbriel. Nearly a century
passed before Gerard Kuiper found Miranda in 1948. And that was it until a NASA robot made it to
distant Uranus. The Voyager 2 spacecraft visited the Uranian system in 1986 and tripled the number of
known moons. Voyager 2 found an additional 10, just 26-154 km (16-96 miles) in diameter: Juliet, Puck,
Cordelia, Ophelia, Bianca, Desdemona, Portia, Rosalind, Cressida and Belinda. Since then, astronomers
using the Hubble Space Telescope and improved ground-based telescopes have raised the total to 27
known moons. Spotting the post-Voyager moons is an impressive feat. They're tiny -- as little as 12-16
km (8-10 miles) across, and blacker than asphalt. And of course, they're nearly 3 billion miles away.
All of Uranus's inner moons (those observed by Voyager 2) appear to be roughly half water
ice and half rock. The composition of the moons outside the orbit of Oberon remains unknown, but they
are likely captured asteroids.
Here's a sampling of some of the unique aspects of the moons:
-Miranda, the innermost and smallest of the five major satellites, has a surface unlike any other moon
that's been seen. It has giant fault canyons as much as 12 times as deep as the Grand Canyon, terraced
layers and surfaces that appear very old, and others that look much younger.
-Ariel has the brightest and possibly the youngest surface among all the moons of Uranus. It has few
large craters and many small ones, indicating that fairly recent low-impact collisions wiped out the large
craters that would have been left by much earlier, bigger strikes. Intersecting valleys pitted with craters
scars its surface.
Neptune (Science)
Like Uranus, Neptune gets its bright
blue coloring from methane gas in its
atmosphere. Hurricane-like storms, similar to
Jupiter’s Great Red Spot, regularly move
across Neptune’s turbulent surface.
The eighth planet from the sun,
Neptune was the first planet located through
mathematical predictions rather than through
regular observations of the sky. (Galileo had
recorded it as a fixed star during
observations with his small telescope in 1612
and 1613.)
When Uranus didn't travel exactly as
astronomers expected it to, a French
mathematician, Urbain Joseph Le Verrier,
proposed the position and mass of another
as yet unknown planet that could cause the
observed changes to Uranus's orbit. After
being ignored by French astronomers, Le
Verrier sent his predictions to Johann
Gottfried Galle at the Berlin Observatory,
who found Neptune on his first night of
searching in 1846. Seventeen days later, its
largest moon, Triton, was also discovered.
Nearly 2.8 billion miles (4.5 billion
kilometers) from the sun, Neptune orbits the
sun once every 165 years. It is invisible to
the naked eye because of its extreme
distance from Earth.
Neptune (Science) Part 2
The main axis of Neptune's magnetic field is "tipped over" by about 47 degrees compared with
the planet's rotation axis. Like Uranus, whose magnetic axis is tilted about 60 degrees from the axis of
rotation, Neptune's magnetosphere undergoes wild variations during each rotation because of this
misalignment. The magnetic field of Neptune is about 27 times more powerful than that of Earth.
Neptune's atmosphere extends to great depths, gradually merging into water and other
"melted ices" over a heavier, approximately Earth-size solid core. Neptune's blue color is the result of
methane in the atmosphere. Uranus's blue-green color is also the result of atmospheric methane, but
Neptune is a more vivid, brighter blue, so there must be an unknown component that causes the more
intense color that we see. The cause of Neptune's bluish tinge remains a mystery.
The only mission to set out to Neptune was the Voyager 2. The Voyager 2 accomplished being
the only human-made object to have flown by Neptune. In the closest approach of its entire tour, the
spacecraft passed less than 5,000 km above the planet's cloud tops. It discovered five moons, four rings,
and a "Great Dark Spot" that vanished by the time the Hubble Space Telescope imaged Neptune five years
later. Neptune's largest moon, Triton, was found to be the coldest known planetary body in the solar
system, with a nitrogen ice "volcano" on its surface. A gravity assist at Neptune shot Voyager 2 below the
plane in which the planets orbit the sun, on a course which will ultimately take the spacecraft out of our
solar system.
Neptune contains about 13 moons, exactly. We don't know with what beverage William Lassell
may have celebrated his discovery of Neptune's moon, Triton, but beer made it possible. Lassell was one of
19th century England's grand amateur astronomers, using the fortune he made in the brewery business to
finance his telescopes. He spotted Triton on 10 October 1846 -- just 17 days after a Berlin observatory
discovered Neptune. Curiously, a week before he found the satellite, Lassell thought he saw a ring around
the planet. That turned out to be a distortion caused by his telescope. But when NASA's Voyager 2 visited
Neptune in 1989, it revealed that the gas giant does have rings, though they're far too faint for Lassell to
have seen them.
Neptune (Science) Part 3
Triton's icy surface reflects so
much of what little sunlight reaches it that
the moon is one of the coldest objects in
the solar system, about -400 degrees
Fahrenheit (-240 degrees Celsius).
Triton is the only large moon in
the solar system that circles its planet in a
direction opposite to the planet's rotation
(a retrograde orbit), which suggests that it
may once have been an independent
object that Neptune captured.
Since Neptune was named for the Roman god
of the sea, its moons were named for various lesser sea
gods and nymphs in Greek mythology. Triton (not to be
confused with Saturn's moon, Titan), is far and away the
largest of Neptune's satellites. Dutch-American
astronomer Gerard Kuiper (for whom the Kuiper Belt was
named) found Neptune's third-largest moon, Nereid, in
He missed Proteus, the second-largest,
because it's too dark and too close to Neptune for
telescopes of that era. Proteus is a slightly non-spherical
moon, and it is thought to be right at the limit of how
massive an object can be before its gravity pulls it into a
Proteus and five other moons had to wait for
Voyager 2 to make themselves known. All six are among
the darker objects found in the solar system. Astronomers
using improved ground-based telescopes found more
satellites in 2002 and 2003, bringing the known total to
Voyager 2 revealed fascinating details about
Triton. Part of its surface resembles the rind of a
cantaloupe. Ice volcanoes spout what is probably a
mixture of liquid nitrogen, methane and dust, which
instantly freezes and then snows back down to the
surface. One Voyager 2 image shows a frosty plume
shooting 8 km (5 miles) into the sky and drifting 140 km
(87 miles) downwind.
Pluto (Science)
Pluto is the second most massive known Dwarf
Planet in the Solar System (after Eris) and the tenth most
massive body observed directly rotating around the Sun.
Normally called as a planet, Pluto is now acknowledged the
largest member of a distinct population known as the
Kuiper Belt. Like other members of the Kuiper belt, Pluto is
composed primarily of rock and ice and is relatively small:
approximately a fifth the mass of the Earth's moon and a
third its volume. It has an eccentric and highly inclined
orbit that takes it from 30 to 49 AU (4.4–7.4 billion km)
from the Sun. This causes Pluto to periodically come closer
to the Sun than Neptune.
From its discovery in 1930 until 2006, Pluto
was considered the Solar System's ninth planet. In the late
1970s, following the discovery of minor planet 2060
Chiron in the outer Solar System and the recognition of
Pluto's relatively low mass, its status as a major planet
began to be questioned. In the late 20th and early 21st
century, many objects similar to Pluto were discovered in
the outer Solar System, notably the scattered disc
object Eris in 2005, which is 27% more massive than Pluto.
On August 24, 2006,
the International Astronomical Union (IAU)
defined what it means to be a "planet"
within the Solar System. This definition
excluded Pluto as a planet and added it as
a member of the new category "dwarf
planet" along with Eris and Ceres. After the
reclassification, Pluto was added to the list
of minor planets. Still a number of
scientists believe that Pluto is and should
be a planet.
Pluto (Science) Part 2
The spacecraft called Voyager 1 could have visited Pluto, but the controllers opted instead
for a close flyby of Saturn’s moon Titan, resulting in a trajectory incompatible with a Pluto flyby.
Voyager 2 had a reasonable trajectory for reaching Pluto. No sincere attempt to explore/investigate
Pluto by spacecraft occurred until the last decade of the 20th century. In August 1992, a JPL
scientist named Robert Staehle telephoned Pluto’s discoverer named Clyde Tombaugh, requesting a
visit to Pluto. In result, the spacecraft, New Horizons set out to Pluto. It was launched successfully
on January 19, 2006. In early 2007 the craft made use of a gravity assist from Jupiter. Its closest
approach to Pluto will be on July 14, 2015; scientific observations of Pluto will begin 5 months
before closest approach and will continue for at least a month after the encounter. New
Horizons captured its first (distant) images of Pluto in late September 2006, during a test of the
Long Range Reconnaissance Imager (LORRI). The images, taken from a distance of approximately
4.2 billion kilometres, confirm the spacecraft's ability to track distant targets, critical for
maneuvering toward Pluto and other Kuiper Belt objects.
Pluto and its largest moon, Charon, are sometimes treated as a binary system because
the barycentre of their orbits does not lie within either body. The IAU has yet to formalize a
definition for binary dwarf planets, and until it passes such a ruling, they classify Charon as
a moon of Pluto. Pluto has two known smaller moons, Nix and Hydra, discovered in 2005.
Dwarf Planets (Science)
A Dwarf Planet, as described as a celestial body rotating the sun that is massive enough
to be spherical as a result of its own gravity but has not cleared its neighboring domain of
planetesimals and is not a satellite. More clearly, it has to have a sufficient mass to overcome its
compressive strength and achieve hydrostatic equilibrium. The expression dwarf planet was
adopted in 2006 as part of a three-way categorization of bodies rotating the Sun, brought by an
increase in discoveries of trans-Neptunian objects that rivaled Pluto in size, and finally precipitated
by the discovery of an even more massive object called: Eris.
This classification states that bodies large enough to have cleared the neighborhood of their
orbit are defined as planets, while those that are not massive enough to be rounded by their own
gravity are defined as small solar system bodies. Dwarf planets come in between. The definition
officially adopted in 2006 has been both praised and criticized, and has been disputed by scientists
such as Alan Stern.
The first manned space craft to discover the Dwarf Planets
was the New Horizons. NASA’s New Horizon’s spacecraft was created
to make the first close-up study of the Dwarf Planets, Pluto, its moons,
and other bitter and chilly worlds in the far away, Kuiper Belt. The
mission though has not accomplished anything yet. It is still in process
of it’s mission.
Another mission that has set out to the Dwarf Planets was
the Dawn. The Dawn was designed to study the situations and
development of the Solar System’s earliest epoch by investigating in
detail two of the largest proto-planets remaining intact since their
creation. The Dawn will visit both the asteroid named Vesta and the
dwarf planet called Ceres (as shown in the picture on the right), and
two asteroid belt worlds that followed very different evolutionary paths.
The Difference Between a Space
Object and a Planet
Rocky asteroids and meteors are closely related objects that are tiny compared to planets –
most are less than 60 miles (100 km) across. Their gravity is too weak to pull them into spherical
shapes, so they exist as jagged chunks of rock and ice. Asteroids and ice dwarfs are fragments
from the early days of the Solar System – space debris that never assembled into larger objects,
and the shattered remains of worlds that might have been.
Though, planets are spherical due to their own gravity, and planets orbit the Sun, and not
another planet. While moons rotate the planets instead. Since the word was coined by the ancient
Greeks, the definition of planet has comprised many different things, often simultaneously. Over
the millennia, use of the term was never strict and its meaning has blurred to include or exclude a
variety of different objects, from the Sun and the Moon to satellites and asteroids.
As you might guess, it's partly an issue of size, with dwarf planets being smaller. But just
how big does a planet need to be to become a full-fledged planet instead of a dwarf? You might
think the minimum size requirement is arbitrary, but the size cutoff is actually based on other
properties of the object and its history in the Solar System.
Both planets and dwarf planets orbit the Sun, not other planets (in which case we call them
moons). Both must be large enough that their own gravity pulls them into the shapes of spheres;
this rules out numerous smaller bodies like most asteroids, many of which have irregular shapes.
Planets clear smaller objects out of their orbits by sucking the small bodies into themselves or
flinging them out of orbit. Dwarf planets, with their weaker gravities, are unable to clear out their
America’s Manned Space Missions
On April 12, 1961, the first human
escaped Earth’s gravity. Yuri Gagarin orbited
the Earth at a height of 187 miles for 108
minutes at a 18,000 miles/hr. His spaceship
was called the Vostok 1. He is often called the
“Columbus of the Cosmos.”
Wernher von Braun, a German rocket
scientist who fled Germany when Hitler wanted
to use his rockets as weapons. He escaped to
the U.S. and led the teams at NASA in the
development of the V2 rockets. He later would
be influential in the creation of the Saturn 5
rocket used in the Apollo Missions.
Apollo 11 was to be the first manned
space flight to land on the moon. It was
launched on July 16, 1969 and included Neil
Armstrong, Michael Collins, and Edwin (Buzz)
Aldrin. They (besides Michael) became the very
first people to step on the moon! Neil
Armstrong was the commander of Apollo 11
and would be one of the first men to set foot
on the Moon. Since Apollo 11, only 6 other
missions have gone to the moon. How many
men have set foot on the moon?
America’s Manned Space Missions
Michael Collins was the pilot of the command
module which would remain in orbit around the
Moon. Collins never got to walk on the moon. Would you still
want to make the journey even if you wouldn’t get to walk
on the moon? Buzz Aldrin was the pilot of the lunar module
and was the second man to set foot on the moon. He left
the lunar module about 12 minutes after Armstrong. Neil
Armstrong took the picture of Aldrin leaving the lunar
module. The lunar module was nicknamed the “Eagle”. As
the Eagle made its approach, Buzz Aldrin made this
Neil Armstrong’s now famous quote:
That's one small step for man, one giant leap for
The astronauts had no need for suitcases due to
the fact that they spent less than 22 hours on the Moon.
They did grab some rock samples, planted a flag and placed
a plaque on the Moon. Some people have said that we never
landed on the moon. The position of the flag is part of their
“proof”. The rod to hold the flag out horizontally would not
extend fully, so the flag ended up with a slight waviness,
giving the appearance of being wind blown.
Space Race (USA vs. USSR)- Rise
of the Superpowers
The Space Race was a mid-to-late twentieth century
competition between the Soviet Union (USSR) and the United
States (US) for supremacy in outer space exploration. Between 1957
and 1975, Cold War rivalry between the two nations focused on
attaining firsts in space exploration, which were seen as necessary for
national security and symbolic of technological and ideological
superiority. The Space Race involved pioneering efforts to
launch artificial satellites, sub-orbital and orbital human
spaceflight around the Earth, and piloted voyages to the Moon. It
effectively began with the Soviet launch of the Sputnik I artificial
satellite on October 4, 1957, and concluded with the cooperative Apollo-Soyuz Test Project human spaceflight mission in July
1975. The Apollo-Soyuz Test Project came to symbolize détente, a
partial easing of strained relations between the USSR and the US. The
Space Race had its origins in the missile-based arms race that
occurred just after the end of the World War II, when both the Soviet
Union and the United States captured advanced German rocket
technology and personnel.
The Sputnik 1 was unmanned and it gathered information
about Earth’s atmosphere and sent signals back to Earth. After that,
the Soviet Union launched Sputnik II in 1957. It contained
information about solar radiation and cosmic rays, and contained a
passenger called Laika, a small dog who provided that living things
could survive the launch and weightlessness of space.
The U.S. was anxious when the Soviet Union first launched
Sputnik I. Americans thought the Soviets were spying from space.
President John F. Kennedy encouraged Americans to support the
space program. The U.S. launched its first unmanned satellite,
Explorer I, in 1958, four months after Sputnik I. Costing
approximately $500 to $700 million dollars for each space shuttle that
Space Race (USA vs. USSR)- Rise
of the Superpowers
During the 1970s, both the USA and
the Soviet Union launched space stations,
where scientists could live for weeks at a
time and carry out experiments. When the
Cold Way ended, the two countries began to
work together. From 1995 to 1998, American
scientists worked on the Russian space
station Mir. At the end of the 20th century,
engineers around the world started work on
an exciting new project, called the
International Space Station. The first two
parts were built in Russia and in the USA.
They were launched separately and were
joined together in space, in December 1998.
The International Space Station (ISS)
became the biggest space station in history
on 2003. The first module was launched in
1998 and the space station was being built
by exactly 16 countries.
What Should Mankind Continue
Exploring In Our Solar System?
I want NASA to send more
manned space crafts to Mars to
discover if there is any life forms living
on Mars. Research says that liquid was
found frozen in the caps of Mars. So, I
just felt so curious about Mars, and
wanted to know if there was any life
on it. If there was, that would be a
great discovery for mankind.
I’m hoping we’ll discover aliens!
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