Learning Our Solar System

Below are pictures and information on Our Solar System. You will find some truly amazing things about the planet we live on which is planet Earth. You will also be learning about other planets out in space.

Our Solar System consists of the Sun and the eight planets, their moons, dwarf planets, asteroids, Kuiper belt objects, Oort Cloud, comets, meteoroids and interplanetary dust.





Facts about Our Solar System

The regions of the Solar System consist of:

1. Our Sun
2. Four Terrestrial Inner Planets: Mercury, Venus, Earth, Mars
3. Asteroid Belt: Composed of small rocky bodies
4. Four Gas Giant Outer Planets: Jupiter, Saturn, Uransus, Neptune
5. Kuiper belt - Second belt composed of icy objects.
6. Oort cloud: Beyond the Kuiper belt

Note: Pluto was demoted in 2006 from a Planet to Dwarf Planet.

How does the Solar System work?

The Sun is the centre of our solar system and celestial bodies such as the planets, their moons, the asteroid belt, comets and other objects revolve around the Sun (gravitationally bound to it). The Sun contains around 98% of all the material in the Solar System.

The boundaries of the solar system's known planets fit within a sphere 50 AU in radius. Beyond that is the Oort Cloud which extends to a distance of 100,000 AU. Beyond that, the nearest star system is Alpha Centauri.

Note: The stars are not part of our solar system. Astronomers have discovered that some other stars, besides our own sun, have their own solar systems around them as well!

What is a Planet?

The International Astronomical Union (IAU) said that the definition for a planet is now officially known as "a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape and (c) has cleared the neighborhood around its orbit." At the same time, new moons are also being discovered, both around existing planets and within these mysterious new worlds. Once the existence of a moon is confirmed and its orbit determined, the moon is given a final name by the International Astronomical Union (IAU), the organization that assumed this task since 1919.

The planets all revolve around the Sun. Six of the eight planets are orbited by natural satellites (moons) after Earth's Moon and each of the outer planets is encircled by planetary rings of dust and other particles. The three dwarf planets are Pluto, the largest known Kuiper belt object; Ceres, the largest object in the asteroid belt and Eris, which lies in the scattered disc.


Planets in the Solar System:

In order of their distances from the Sun, the planets are:

1. Mercury

5. Jupiter

2. Venus

6. Saturn

3. Earth

7. Uranus

4. Mars

8. Neptune




Our Sun is our closest star to our Earth. It is at least 4.5 billion years old. Without the Sun, the Earth would not be able to support life.

How does the Sun work?

The Sun stays lit by converting hydrogen into helium like a big atomic furnace. As a result, tremendous amount of energy is released.

Scientists can only study the sun from spacecraft above our atmosphere because the Earth's atmosphere absorbs X-rays and solar X-rays. Such spacecraft include SOHO ( ESA's Solar and Heliospheric Observatory) and Ulysses.

Why is it important?

The Sun is important because it provides the Earth heat, it creates our daylight by emiting electromagnetic radiation, it allows plants to grow via photosynthesis which in turn absorb carbon dioxide and create oxygen. It is one of the prime ingredients for most Earth life-forms.

There are exceptions such as an lifeforms which have been found near ultra-hot underwater volcanic vents.


The Planet Mercury is the closest planet to our sun and is the smallest planet in the solar system.

It has no natural satellites and no substantial atmosphere.

Facts about Planet Mercury

* Diameter: 4,878km (3,032 miles) at its equator, which is about two-fifths of Earth's diameter.

* Temperature: "This slow rate, combined with mercury's nearness to the sun, causes a daytime temperature of more than 400 °C. In the nightime, heat radiates away quickly and the temperature may be as low as -200 °C"

* Orbit: 57,910,000 km (0.38 AU) from Sun. Orbiting the Sun once every 88 days.

* Average Distance: About 58 million km (36 million miles)

* Time to Rotate: 58.6 days

* Mass: 3.30e23 kg (5.5% of Earth's)

* Moons: 0

* Period of Rotation: 58.6462 days.


Mercury has a very elliptical (oval-shaped) orbit. At perihelion (at its closest point) it is about 46 million km (28.58 million miles) from the Sun, but at aphelion (at its farthest point) it is 70 million km. Mercury is about 77.3 million km (48 million miles) from Earth at its closest approach. Mercury is not easily seen from Earth due to its small angular separation from the Sun. Mercury moves around the sun faster than any other planet. Mercury travels about 48 km (30 miles) per second and it takes 88 Earth days to orbit the sun. The Earth goes around the sun once every 365 days (one year).


The planet rotates once about every 59 Earth days, a rotation slower than that of any other planet except Venus. As a result of the planet's slow rotation on its axis and rapid movement around the sun, a day on Mercury lasts 176 Earth days (interval between one sunrise and the next).


Mercury is the second densest major body in the solar system after Planet Earth and its density is slightly less than the Earths. Mercury's smaller mass makes its force of gravity only about a third as strong as that of the Earth. An object that weighs 100 pounds on the Earth would weigh only about 38 pounds on Mercury.

Mercury has a large iron core which is most likely at least partially molten and generates a magnetic field about 1% as strong as that of Earth's. Mercury's interior appears to resemble that of the Earth. Both planets have a rocky layer called a mantle beneath their crust and both planets have an iron core.


The surface of Mercury consists of cratered terrain and smooth plains and many deep craters similar to those on the moon. The craters formed when meteors or small comets crashed into the planet. The largest known crater is Caloris Basin, with a diameter of 1300 km (800 miles).

Like the other terrestrial planets (Venus, Earth and Mars) Mercury is made mostly of rock and metal. Mercury's surface appears to be much like that of the moon. It reflects approximately 6 percent of the sunlight it receives, about the same as the moon's surface reflects. Like the moon, Mercury is covered by a thin layer of minerals called silicates in the form of tiny particles.


Scans of Mercury made by Earth-based radar indicate that craters at Mercury's poles contain water ice. The floors of the craters are permanently shielded from sunlight, so the temperature never gets high enough to melt the ice.


Mercury is a planet of extreme temperature variations. It is hotter on Venus, but with less fluctuations. The temperature on the planet may reach 450 degrees C (840 degrees F) during the day. But at night, the temperature may drop as low as -170 degrees C (-275 degrees F). The sunlight on Mercury’s surface is 6.5 times as intense as it is on Earth due its closeness to the sun.


Mercury is dry, extremely hot and almost airless. Planet Mercury is too small for its gravity to retain any significant atmosphere over long periods of time. The weak atmosphere contains hydrogen, helium, oxygen, sodium, calcium and potassium.

Due to the heat of the planet, the very thin atmosphere is blasted off its surface by the solar wind and quickly escapes into space. Mercury's atmosphere is constantly being replenished.

Mercury does not have enough atmosphere to slow down meteoroids and burn them up by friction. The sun's rays are approximately seven times as strong on Mercury as they are on the Earth. The sun also appears about 2 1/2 times as large in Mercury's sky as in the Earth's.


The plant and animal life of the Earth could not live on Mercury because of the lack of oxygen and the intense heat. Scientists doubt that the planet has any form of life.


Because of Mercury's size and nearness to the sun, the planet is often hard to see from the Earth without a telescope. At certain times of the year, Mercury can be seen low in the western sky just after sunset. At other times, it can be seen low in the eastern sky just before sunrise.


When viewed through a telescope, Mercury can be seen going through ‘changes’ in shape and size. These apparent changes are called phases and resemble those of the moon. They result from different parts of Mercury's sunlit side being visible from the Earth at different times.


Mercury has been known since ancient times. Until the mid-1960's, astronomers believed that Mercury rotated once every 88 Earth days, the same time the planet takes to go around the sun. If Mercury did this, one side of the planet would always face the sun and the other side would always be dark. However, radar studies conducted in 1965 showed that the planet rotates once in about 59 days.

The only spacecraft to come close to Mercury was Mariner 10 from 1974 to 1975, which was only able to map 40%–45% of the planet's surface.




Venus is the second planet from the sun in our solar system. It is the hottest planet in our Solar System. This planet is covered with fast-moving sulphuric acid clouds which trap heat from the Sun. Its thick atmosphere is mostly carbon dioxide. Venus has an iron core but only a very weak magnetic field.
This is a planet on which a person would asphyxiate in the poisonous atmosphere, be cooked in the extremely high heat, and be crushed by the enormous atmospheric pressure.

Venus is also known as the "morning star" or the "evening star" since it is visible and quite bright at either dawn or dusk. It is only visible at dawn or dusk since it is closer to the sun than we are.

Like the moon, Venus' appearance from Earth changes as it orbits around the Sun. It goes from full to gibbous to crescent to new and back.

Venus is about 7,521 miles (12,104 km) in diameter. This is about 95% of the diameter of the Earth. Venus is the closest to Earth in size and mass of any of the other planets.

Venus' mass is about 4.87 x 1024 kg. The gravity on Venus is 91% of the gravity on Earth. A 100-pound person would weigh 91 pounds on Venus.

The density of Venus is 5,240 kg/m3, slightly less dense than the Earth and the third densest planet in our Solar System (after the Earth and Mercury).

Venus rotates VERY slowly. Each day on Venus takes 243 Earth days. A year on Venus takes 224.7 Earth days. It takes 224.7 Earth days for Venus to orbit the sun once. The same side of Venus always faces Earth when the Earth and Venus are closest together.

Venus is 67,230,000 miles (108,200,000 km) from the sun. Venus has an almost circular orbit. On average, Venus is 0.72 AU, 67,230,000 miles = 108,200,000 km from the sun.

Venus rotates in the opposite direction of the Earth (and the other planets, except possibly Uranus). Looking from the north, Venus rotates clockwise, while the other planets rotate counterclockwise. From Venus, the Sun would seem to rise in the west and set in the east (the opposite of Earth). No one knows why Venus has this unusual rotation.

Venus is the hottest planet in our Solar System. Its cloud cover traps the heat of the sun (the greenhouse effect), giving Venus temperatures up to 480°C. The mean temperature on Venus is 726 K (452°C = 870°F).

Venus has no moons.




Facts about Planet Earth

* Diameter: 12,800 km.

* Atmosphere: The Earth's atmosphere is a thin layer of gases that surrounds the Earth. It is composed of 78% nitrogen, 21% oxygen, 0.9% argon, 0.03% carbon dioxide, and trace amounts of other gases.

The atmosphere was formed by planetary degassing, a process in which gases like carbon dioxide, water vapor, sulphur dioxide and nitrogen were released from the interior of the Earth from volcanoes and other processes. Life forms on Earth have modified the composition of the atmosphere since their evolution.

* Natural Satellites: 1 - the Moon

* Earth Year: 365 days (rotation around the sun)

* Earth Day: 24 hours

* Surface: 71% of Earth's surface is covered in water.

* Temperature Range: The temperature on Earth ranges from between -127°F to 136°F (-88°C to 58°C; 185 K to 311 K). The coldest recorded temperature was on the continent of Antarctica (Vostok in July, 1983). The hottest recorded temperature was on the continent of Africa (Libya in September, 1922).

* Age: more than 4.5 billion years old.

* Average Distance from Sun: 149,597,870 km (93 million miles)

* Average distance from Earth to Moon: 384 000 km (238 607 miles). The Moon orbits Earth in 27.3217 days.

* Tilt: The Earth's axis is tilted from perpendicular to the plane of the ecliptic by 23.45°. This tilting is what gives us the four seasons of the year: Summer, Spring, Winter and Autumn. Since the axis is tilted, different parts of the globe are oriented towards the Sun at different times of the year. This affects the amount of sunlight each receives.

* Orbits the Sun: Speed of 107,870 km per hour (67,027 miles) per hour.

The Earth consists of a gaseous atmosphere, the hydrosphere (all water on Earth), the lithosphere, mantle, and core. Water in the form of the oceans covers approximately 70% of the earth's surface. The remaining 30% is land. There are five continents: (Africa and Asia), America (North and South America), Europe, Antarctica and Australia.

The following are some interesting facts:

1. Mount Everest is the highest point on the surface.
2. The largest volcano on earth is Mauna Loa volcano in Hawaii.
3. The longest river is the Nile River in Africa is 6,695 kilometers (4,160 miles) long.
4. The driest place on Earth is the Atacama Desert in Chile.
5. Grand Canyon is the world's largest canyon.
6. Caspian Sea is the largest lake in the world by size and volume. It is located between southeast Europe and west Asia.
7. The Sahara Desert in northern Africa is the world’s largest desert.
8. The world’s deepest lake is Lake Baikal in the south central part of Siberia is 5,712 feet (1.7 kilometers) deep.
9. Greenland is the world’s largest island. Note: Australia is a continent.
10. Coldest temperature was minus 89.2 °C (-128.5?F) in Vostok, Antarctica, 1983. The highest temperature was 58°C (136.4?F) at Al'Aziziyah, Libya, on 13th September 1922.

How many Man-made Satellites are Orbitting the Earth?

The Goddard Space Flight Center's lists 2,271 satellites currently in orbit. Russia has the most satellites currently in orbit, with 1,324 satellites, followed by the U.S. with 658. through this web site you will find info on earth related satellites and space-ships (spacecraft).

Man-made Structure Visible from Space

The Only Man-made Structure Visible from Space is the Great Wall of China It stretches over 6,000 kilometers (nearly 4,000 miles).





The Moon is Earth's nearest natural satellite. Our Moon is bigger than Planet Pluto. It can be seen clearly with your eyes. For better viewing you can use binoculars, or a telescope. Galileo in 1609 was the first to look at it through a telescope. The Moon is about 4 and a 1/2 billion years old. It is the only object in the solar system visited by humans.

Moon Facts

The moon is about one quarter the size of Earth and it has about one-sixth of the Earth's gravity. It has a black sky, has almost no atmosphere due to its weak gravity. Without an atmosphere, there is no wind, no clouds and no rain.

* Distance: Mean distance from Earth to the Moon is 384,000km (238,900 miles)

* Diameter: 3,476km (2,160 miles)

* Mass: 7.35 X 1022 kg. This about one-eightieth of the Earth's mass.

* Moon's rotation: Rotates about its own axis in 27 days and 8 hours, which is about the same time it takes to orbit the earth. Hence the same face of the moon is always facing the Earth. The far side always faces away and cannot be seen from Earth. It has been photographed by spacecraft.

* Escape velocity: 2.38 km/sec

* Moon Surface: It is covered with craters, lava plains, mountains and valleys. No active volcanos.

* Temperature:

The temperature on the Moon ranges from daytime highs of about 130°C = 265°F to nighttime lows of about -110°C = -170°F

* Mass: 0.012 (Earth = 1)

Phasing of our Moon

Our Moon goes through phases during the lunar month. The lunar month is the 29.53 days it takes to go from one new moon to the next. The moon phase is the shape you see which follows the same pattern every four weeks.

The shape of the moon appears to change due to the different amounts of light being reflected on it and is caused by the relative positions of the Earth, moon, and sun. At full Moon and new Moon, the Sun, Earth and Moon are lined up.


Day 0 - New Moon is when no light is reflected so the moon appears dark because it is between our sun and the Earth and the brightness of our sun outshines the Moon.

Day 4 - Waxing Crescent is when there is a little bit of light on the moon and its illuminated surface appears to grow (wax) to full.

Day 7 - First Quarter Moon is when half of the Moon's surface is illuminated and looks like half-circle. It is is one-quarter of the way through the lunar month.

Day 10 - Waxing Gibbous is when the moon is nearly, but not full.

Day 14 - Full Moon is when it is farther away from the sun than the earth and appears as a bright, round disk.

Day 18 - Wanning Gibbous is when it wanes (grows thinner/decreases each night).

Day 22 - Last Quarter is when the moon appears as a half-circle again. The dark side in the first quarter phase is now the lit side.

Day 26 - Waning Crescent

Day 29 - New Moon is repeated each lunar month and is the start of new cycle.

Exploration Highlights:

- First photograph of the far side of the Moon was by Soviet Luna 3 spacecraft in October 1959.
- First soft landing on the Moon was by Soviet Luna 9, launched on 31st January 1966 and landed on 3rd February 1966.
- First manned flight around the moon was Apollo 8 in December 1968.
- First manned landing and walk was during the Apollo 11 mission on July 20th 1969. The first man to walk on the moon was Neil Armstrong on the Apollo Mission in 1969.

Arnaldo Tamayo Méndez Astronaut (1980)

Guion Bluford Astronaut (1983)

Guion Bluford was the first African American in space, but the first person of African American ancestry in space was the Cuban Cosmonaut Arnaldo Tamayo Méndez.


Arnaldo Tamayo Méndez Astronaut (1980)



Guion Bluford Astronaut (1983)

The first black American astronaut, Guion S. Bluford, into space as a mission specialist.




Bluford became a NASA astronaut in August 1979. His technical assignments have included working with Space Station operations, the Remote Manipulator System (RMS), Spacelab systems and experiments, Space Shuttle systems, payload safety issues and verifying flight software in the Shuttle Avionics Integration Laboratory (SAIL) and in the Flight Systems Laboratory (FSL). Bluford was a mission specialist on STS-8, STS-61-A, STS-39, and STS-53[4].

Bluford's first mission was STS-8, which launched from Kennedy Space Center, Florida, on August 30, 1983. This was the third flight for the Orbiter Challenger and the first mission with a night launch and night landing. During the mission, the STS-8 crew deployed the Indian National Satellite (INSAT-1B); operated the Canadian-built RMS with the Payload Flight Test Article (PFTA); operated the Continuous Flow Electrophoresis System (CFES) with live cell samples; conducted medical measurements to understand biophysiological effects of space flight; and activated four "Getaway Special" canisters. STS-8 completed 98 orbits of the Earth in 145 hours before landing at Edwards Air Force Base, California, on September 5, 1983.

Bluford then served on the crew of STS-61-A, the German D-1 Spacelab mission, which launched from Kennedy Space Center, Florida, on October 30, 1985. This mission was the first to carry eight crew members, the largest crew to fly in space and included three European payload specialists. This was the first dedicated Spacelab mission under the direction of the German Aerospace Research Establishment (DFVLR) and the first U.S. mission in which payload control was transferred to a foreign country (German Space Operations Center, Oberpfaffenhofen, Germany). During the mission, the Global Low Orbiting Message Relay Satellite (GLOMR) was deployed from a "Getaway Special" (GAS) container, and 76 experiments were performed in Spacelab in such fields as fluid physics, materials processing, life sciences, and navigation. After completing 111 orbits of the Earth in 169 hours, Challenger landed at Edwards Air Force Base, California, on November 6, 1985.

Bluford also served on the crew of STS-39, which launched from the Kennedy Space Center, Florida, on April 28, 1991, aboard the Orbiter Discovery. The crew gathered aurora, Earth-limb, celestial, and Shuttle environment data with the AFP-675 payload. This payload consisted of the Cryogenic Infrared Radiance Instrumentation for Shuttle (CIRRIS-1A) experiment, Far Ultraviolet Camera experiment (FAR UV), the Uniformly Redundant Array (URA), the Quadrupole Ion Neutral Mass Spectrometer (QINMS), and the Horizon Ultraviolet Program (HUP) experiment. The crew also deployed and retrieved the SPAS-II which carried the Infrared Background Signature Survey (IBSS) experiment. The crew also operated the Space Test Payload-1 (STP-1) and deployed a classified payload from the Multi-Purpose Experiment Canister (MPEC). After completing 134 orbits of the Earth and 199 hours in space, Discovery landed at the Kennedy Space Center, Florida, on May 6, 1991.

More recently, Bluford served on the crew of STS-53 which launched from the Kennedy Space Center, Florida, on December 2, 1992. The crew of five deployed the classified Department of Defense payload DOD-1 and then performed several Military-Man-in-Space and NASA experiments. After completing 115 orbits of the Earth in 175 hours, Discovery landed at Edwards Air Force Base, California, on December 9, 1992.

With the completion of his fourth flight, Bluford has logged over 688 hours in space.

Bluford left NASA in July 1993 to take the post of Vice President/General Manager, Engineering Services Division of NYMA, Greenbelt, Maryland. In May, 1997, he became Vice President of the Aerospace Sector of Federal Data Corporation and in October, 2000, became the Vice President of Microgravity R&D and Operations for the Northrop Grumman Corporation. He retired from Northrop Grumman in September, 2002 to become the President of the Aerospace Technology, an engineering consulting organization in Cleveland, Ohio.

He was inducted into the International Space Hall of Fame in 1997.


Dr. Mae C. Jemison Astronaut
The First African-American Woman in Space





Dr. Mae Jemison was the science mission specialist on STS-47 Spacelab-J (September 12-20, 1992). STS-47 was a cooperative mission between the United States and Japan. The eight-day mission was accomplished in 127 orbits of the Earth, and included 44 Japanese and U.S. life science and materials processing experiments. Dr. Mae Jemison was a co-investigator on the bone cell research experiment flown on the mission. The Endeavour and her crew launched from and returned to the Kennedy Space Center in Florida. In completing her first space flight, Dr. Mae Jemison logged 190 hours, 30 minutes, 23 seconds in space, making her the first African-American woman in space.






Chemical engineer, scientist, physician, teacher and astronaut, Dr. Mae Jemison has a wide range of experience in technology, engineering, and medical research. In addition to her extensive background in science, she is well-versed in African and African-American Studies, speaks fluent Russian, Japanese, and Swahili, as well as English and is trained in dance and choreography.
On October 17, 1956, the city of Decatur, AL saw the birth of a remarkable woman, Mae Jemison. The youngest of three children born to Charlie Jemison, a maintenance worker and his wife, Dorothy, a teacher, Mae moved with her family to Chicago at the age of three.

After graduating from Morgan Park High School in 1973 at the age of 16, Dr. Mae Jemison earned a BS in Chemical Engineering from Stanford University, while also fulfilling the requirements for a BA in African-American Studies. After earning these degrees in 1977, she attended Cornell University and received a Doctor of Medicine degree in 1981. During medical school she traveled to Cuba, Kenya and Thailand, providing primary medical care to people living there.

Demonstrating her compassion, Dr. Mae Jemison served in the Peace Corps, from January 1983 to June 1985. She shared her abilities in Sierra Leone and Liberia, West Africa as the area Peace Corps medical officer. Among her duties, she supervised the pharmacy, laboratory, medical staff as well as provided medical care, wrote self-care manuals, developed and implemented guidelines for health and safety issues. Also working in conjunction with the Center for Disease Control (CDC) she helped with research for various vaccines.

Upon completion of her Peace Corps duties, Dr. Mae Jemison returned to the US, accepting a position with the CIGNA Health Plans of California as a general practitioner in Los Angeles, California. Having a desire to do more with her life, she enrolled in graduate classes in engineering and applied to NASA for admission to the astronaut program. She was turned down on her first application, but persevered and in 1987 was accepted on her second application. She became one of the fifteen candidates accepted from over 2,000 applicants.

When Dr. Mae Jemison successfully completed her astronaut training program in August 1988, she became the fifth black astronaut and the first black female astronaut in NASA history. Her technical assignments included: launch support activities at the Kennedy Space Center in Florida; verification of Shuttle computer software in the Shuttle Avionics Integration Laboratory (SAIL), Science Support Group activities.

Dr. Mae Jemison was the science mission specialist on STS-47 Spacelab-J (September 12-20, 1992). STS-47 was a cooperative mission between the United States and Japan. The eight-day mission was accomplished in 127 orbits of the Earth, and included 44 Japanese and U.S. life science and materials processing experiments. Dr. Mae Jemison was a co-investigator on the bone cell research experiment flown on the mission. The Endeavour and her crew launched from and returned to the Kennedy Space Center in Florida. In completing her first space flight, Dr. Mae Jemison logged 190 hours, 30 minutes, 23 seconds in space, making her the first African-American woman in space.


She says, “I had to learn very early not to limit myself due to others’ limited imaginations. I have learned these days never to limit anyone else due to my limited imagination.” Dr. Mae C Jemison Website
In 1993, Dr. Mae Jemison resigned from NASA and founded the Jemison Group, Inc. to research, develop and implement advanced technologies suited to the social, political, cultural and economic context of the individual, especially for the developing world. Current projects include: Alpha, (TM) a satellite based telecommunication system to improve health care in West Africa; and The Earth We Share, (TM) an international science camp for students ages 12 to 16, that utilizes an experiential curriculum. Among her current projects are several that focus on improving healthcare in Africa. she is also a professor of environmental studies at Dartmouth College.

Dr. Mae Jemison is the host and a technical consultant to "World of Wonders" series produced by GRB Entertainment and seen weekly on the Discovery Channel. She feels very honored by the establishment (1992) of the MAE C. JEMISON ACADEMY, an alternative public school in Detroit.

Awards and honors she has received include Essence Award (1988), Gamma Sigma Gamma Women of the Year (1989), Honorary Doctorate of Science, Lincoln College, PA (1991), Honorary Doctor of Letters, Winston-Salem, NC (1991), McCall's 10 Outstanding Women for the 90's (1991), Pumpkin Magazine's (a Japanese Monthly) One of the Women for the Coming New Century (1991), Johnson Publications Black Achievement Trailblazers Award (1992), Mae C. Jemison Science and Space Museum, Wright Jr. College, Chicago, (dedicated 1992), Ebony's 50 Most Influential women (1993), Turner Trumpet Award (1993), and Montgomery Fellow, Dartmouth (1993), Kilby Science Award (1993), Induction into the National Women's Hall of Fame (1993), People magazine's 1993 "50 Most Beautiful People in the World"; CORE Outstanding Achievement Award; National Medical Association Hall of Fame.

Dr. Mae Jemison is a member of the Association for the Advancement of Science; Association of Space Explorers: Honorary member of Alpha Kappa Alpha Sorority, Inc.; board of Directors of Scholastic, Inc.; Board of Directors of Houston's UNICEF; Board of Trustees Spelman College; Board of Directors Aspen Institute; board of Directors Keystone Center; and the National Research Council Space Station Review Committee. She has presented at the UN and internationally on the uses of space technology, was the subject of a PBS Documentary, THE NEW EXPLORERS; ENDEAVOUR by Kurtis Production and appeared in an episode of STAR TREK: THE NEXT GENERATION.

She resides in Houston Texas



Did you know?

* The main cause of the rise and fall of ocean tides is the moon's gravitational pull on the Earth.

* Regolith is the soil that covers the Moon and is composed of rock fragments and fine dust grains. The big dark spots of wide flat areas of rock are called seas or maria.

* Is the moon made of cheese? No cheese has ever been found on the moon.

* The craters on the surface were made when meteorites (space rock) hit the moon.

* There is no such thing as the "dark side of the moon". The sun shines on all sides.



Mars, the red planet, is the fourth planet from the sun and the most Earth-like planet in our solar system. It is about half the size of Earth and has a dry, rocky surface and a very thin atmosphere.

The surface of Mars is dry, rocky, and mostly covered with iron-rich dust. There are low-lying plains in the northern hemisphere, but the southern hemisphere is dotted with impact craters. The ground is frozen; this permafrost extends for several kilometers.

The north and south poles of Mars are covered by ice caps composed of frozen carbon dioxide and water.

Mars is about 4,222 miles (6790 km) in diameter. This is 53% (a little over half) of the diameter of the Earth.
Mars' mass is about 6.42 x 10^23 kg. This is 1/9th of the mass of the Earth. A 100-pound person on Mars would weigh 38 pounds.
Each day on Mars takes 1.03 Earth days (24.6 hours). A year on Mars takes 687 Earth days; it takes this long for Mars to orbit the sun once.

Mars is 1.524 times farther from than the sun than the Earth is. It averages 141.6 million miles (227.9 million km) from the sun. Its orbit is very elliptical; Mars has the highest orbital eccentricity of any planet in our Solar System except Pluto.

Mars has a very thin atmosphere. It consists of 95% carbon dioxide (CO2), 3% nitrogen, and 1.6% argon (there is no oxygen). The atmospheric pressure is only a fraction of that on Earth (about 1% of Earth's atmospheric pressure at sea level), and it varies greatly throughout the year.
There are large stores of frozen carbon dioxide at the north and south poles. During the warm season in each hemisphere, the polar cap partly melts, releasing carbon dioxide. During the cold season in each hemisphere, the polar cap partly freezes, capturing atmospheric carbon dioxide.

The atmospheric pressure varies widely from season to season; the global atmospheric pressure on Mars is 25% different (there is less air, mostly carbon dioxide) during the (northern hemisphere) winter than during the summer. This is mostly due to Mars' highly eccentric orbit; Mars is about 20% closer to the Sun during the winter than during the summer. Because of this, the northern polar cap absorbs more carbon dioxide than the southern polar cap absorbs half a Martian year later.

Occasionally, there are clouds in Mars' atmosphere. Most of these clouds are composed of carbon dioxide ice crystals or, less frequently, of frozen water crystals.

There are a lot of fine dust particles suspended in Mars' atmosphere. These particles (which contain a lot of iron oxide) absorb blue light, so the sky appears to have little blue in it and is pink/yellow to butterscotch in color.

Mars' surface temperature averages -81 °F (-63 °C). The temperature ranges from a high of 68° F(20° C) to a low of -220° F(-140° C). Mars is much colder than the Earth.

Mars has 2 tiny moons, Phobos and Deimos. They were probably asteroids that were pulled into orbit around Mars.


Most Near Earth Asteroids are believed to be main belt asteroids that were knocked out of the belt by collisions with other asteroids and/or by the gravitational forces of Jupiter. Some NEAs may actually be remnants of dead comets. The orbits of near Earth asteroids are thought to be influenced by gravitational interactions with the Sun or terrestrial planets or by collisions with other bodies.

What is a Near Earth Object?

A Near Earth Object (NEO) is an asteroid or comet whose orbit brings it close to the Earth.

This includes an object that will come close to the Earth at some point in its future orbital evolution. NEOs generally result from objects that have experienced gravitational perturbations from nearby planets, moving them into orbits that allow them to come near to the Earth.


Asteroid Belt

The Asteroid Belt is the space between Mars and Jupiter.

It contains irregularly shaped chunks of debris called asteroids. Scientists believe the asteroids are the pieces of a planet that never formed. One possible theory is the ongoing gravitational tug-of-war between Jupiter and Mars has prevented the pieces from bonding together, hence, this planet was never created.


The Planet Jupiter is the LARGEST PLANET in our Solar System. Jupiter has at least 39 moons and they include: Europa, Io, Callisto and Ganymede.

Jupiter was explored in flybys in the 1970s by NASA's Pioneer 10 and 11 and Voyager 1 and 2 spacecraft, and is currently being studied by the Galileo spacecraft.

In May 2002, astronomers announced an additional 11 moons for Planet Jupiter. All 11 are small bodies with diameters estimated to be between 2 and 4 kms. The moons are inclined, highly elliptical retrograde orbits with an average distance of 21 million kms. from the giant planet. The number of moons now known to orbit Jupiter are 39 and makes it the planet with the most moons.

These discoveries have been possible by a new generation of electronic cameras that can scan wide areas of the sky and detect dim objects, making them very efficient tools to search for small moons.


The Planet Saturn is the second largest planet. It is the next planet after Jupiter.

It has at least 31 moons. These include Titan, Hyperion, Mimas, Enceladus, Rhea, and Phoebe.

Facts about Planet Saturn

* Diameter: 120,660 km. It is about 10 times larger than our Earth

* Temperature: –178°C

* Distance from Earth: At its closest, Saturn is 1190.4 million km

* Atmosphere: Hydrogen and helium

* Surface: consists of liquid and gas.

* Rotation of its axis: 10 hours, 40 min, 24 sec

* Rotation around the Sun: 29.5 Earth years

Saturn Space Probes:

Saturn has been visited in flybys in the 1970s by NASA's Pioneer 11 and in 1980-81 by the Voyager 1 and 2 spacecraft.

The Cassini spacecraft, launched in 1997 arrived at Saturn in July 2004. The Hugens probe will explore the moon -Titan.


The Planet Uranus is the third largest planet in the solar system, is a Gas Giant and is the seventh planet from the sun. Planet Uranus has rings like Planet Jupiter, Saturn and Neptune.

The Planet Uranus has been visited by the Voyager 2 spacecraft

Facts about Planet Uranus

* Diameter: 51,500 km (32,000 miles)

* Temperature: -197.15 C (-322.87° F)

* Orbit: Takes 84 years to complete an orbit.

* Average Distance: 2,870,972,200 km (1,783,939,400 miles - 19.2 AU) from Sun

* Mass: 8.6849 x 1025 kg

* Moons: 27

* Period of Rotation: 17.24 hours (retrograde: spins backwards compared to most other planets)


Uranus' atmosphere is about 83% hydrogen, 15% helium and 2% methane. There are also traces of water and ammonia. The planet's atmospheric details are very difficult to see in visible light. The methane gas above the cloud layers gives it a blue-green colour.



Uranus is the only planet in our Solar System to spin on its side. The axis of rotation tilt is 98 degrees. The severe tilt to its rotational axis may have resulted from a great collision long ago.


Uranus is a 'Gas Giant' with no solid surface. It may have a small, silicate-rich core, but most of its gas consists of water, ammonia and methane. Its surface area is about 8,115,600,000 km2 .

More than 80 percent of the mass of Uranus is contained in an extended liquid core consisting primarily of 'icy' materials (water, methane and ammonia) with higher-density material at depth.


If you know where to look, it can occasionally be spotted with the naked eye, however, it can be hard to see due to the similarity of the background stars.


The only spacecraft to visit Planet Uranus was the Voyager 2 spacecraft in a flyby in 1986. It discovered 10 moons and two rings in addition to studying moons and rings previously seen from Earth.

Moons of Uranus

The Planet Uranus has many moons. Five of largest are Miranda, Titania, Oberon, Umbriel, Ariel. The largest moon is Titania with a radius of only 788.9 km (less than half that of our Moon).




The Planet Neptune is the eighth planet from the sun. It is also known as the Blue Giant. Neptune is the fourth and outermost of the gas giant planets and also has rings. Its atmosphere is mostly hydrogen and helium.

Neptune has been visited by only one spacecraft, Voyager 2 on Aug 25 1989. It was the last stop in 1989 for the Voyager 2 spacecraft on its grand tour of the solar system.

Recent knowledge has been gained by ground-based telescopes and the Hubble Space Telepscope.

Due to Pluto's eccentric orbit, Neptune at times becomes the most distant planet from the Sun for a few years.

Planet Neptune Facts:

Mass: 17.15 Earth-masses

Number of known satellites: 8

Length of Year: 164.8 Earth-years

Mean Distance from the Sun: 4,500 million kilometers

Mean Orbital Velocity: 5.4 kilometers per second

Length of Day: 16.11 hours, 0.67 Earth-day

Equatorial diameter: 49,500 kilometers
Atmospheric components: 74% hydrogen, 25% helium, 1% methane

Moons of Planet Neptune

Neptune has 8 known moons: Triton, Thalassa, Naiad, Despina, Galatea, Larissa, Proteus and Nereid

Triton has the coldest temperatures in the solar system. Voyager observed geysers.
The Great Dark Spot
Voyager 2 observed the Great Dark Spot. Recent observations made with the Hubble Space Telescope indicate that the Great Dark Spot no longer exists.



Pluto is the farthest known planet from the Sun. It the only one planet that has not been visited by spacecraft. It has one moon called Charon.

Facts about Planet Pluto

* Diameter: 2324 km (1444 miles).

* Surface composition: Nitrogen, carbon monoxide, methane and water ices

* Average surface temperature: -233ºC (-382ºF)

* Mass: 0.002 (Earth = 1)

* Gravity: 0.07 (Earth = 1)

* Average distance from the Sun: 5.9 billion kilometres.

* Rotation Period: 6.39 Earth days (length of day)

* Orbital period around the sun: 248 Earth years (length of year)

* Rings = 0

* Moons = 1

* Average distance between Pluto and Charon: 19,600 Kms

The Orbit of Planet Pluto

Pluto's orbit from the Sun varies from 4.4 to 7.7 billion kms and for the most of its orbit it is the outer most planet. Between 1979 and 1999 Pluto was actually closer to the Sun than Neptune and the closest approach to the sun (perihelion) was in September 1989.

Due to the changes in orbit in time, Pluto has a unique atmsophere that transforms at various stages of its orbit. As its orbit approaches the Sun, its atmosphere begins to form. The frozen atmosphere melts as it comes closer. As Pluto moves further out its atmsophere will freeze.

Charon Moon

Charon was discovered in 1978. Its diameter is 1212 km (753 miles) which is more than half as wide in size as Pluto and the Pluto-Charon system is like a double planet. Charon orbits Pluto every 6.4 days and has a synchronous orbit (the pair show the same face to each other all the time). To an observer on the planet, Charon appears to be stationary in the sky like a geostationary satellite orbiting the Earth.