Messenger Enters Mercury’s Orbit

On Thursday, March 18^th the Messenger unmanned spacecraft entered Mercury’s orbit.  The last time a spacecraft sent to Mercury was Mariner 10 in 1974 and at that time Mariner 10 was only able to photograph 75% of Mercury’s surface.  Messenger will orbit Mercury for one year and will map the entire surface including color photographs.  On April 4^th, the science portion of the mission will begin as NASA scientists and engineers will begin getting data to interpret from Mercury’s surface.  Over the next few months we should be getting some never before seen images of Mercury.  NASA has a website dedicated Messenger webpage with updates on the mission and photographs.

Weather on Mercury today: very hot (again)

Mercury is a strange, small planet.  Mercury is a bit smaller than Earth’s moon.  Mercury takes 88 Earth days to circle the sun – this is the length of its year.  Oddly, one day on Mercury is equal to 59 days on Earth.  It takes Mercury 1,407 hours to rotate 360^o.  Mercury does not have an atmosphere to retain heat so its temperatures range from 800 ^oF in the day to -279 ^oF at night.  Mercury is a dense planet and its core is 65% iron in a form that is not normally seen on Earth.  This composition is unexpected in such a small planet.  Some scientists theorize that Mercury could have been a larger planet at one time and some sort of massive collision caused it to lose its outer layers.  The elemental composition of Mercury is one of the topics that is being studied in the Messenger mission.  You can learn more about Mercury on NASA’s Mercury page.

Super Moon on Saturday, March 19th!

On Saturday March 19^th we will see a really big full Moon.  In fact, scientists call it a Super Moon.  (Creative bunch, aren’t they?)  The moon will look bigger than it has since March 1983. 

Full Moons look different in size due to the closeness of the Moon’s orbit to Earth.  Moons do not orbit the Earth in a circular orbit but rather in an elliptical orbit.  (The video here from NASA shows the elliptical orbit.)  On Saturday, the moon will be at the closest point to Earth in 18 years.  The Moon will look 14% larger and 30% brighter.  Time to take out your cameras and telescopes!

Some reporting on the internet has incorrectly hypothesized that the upcoming Super Moon influenced the tsunami in Japan last week.  This is not true.  The Moon does not have enough gravitational pull at any point in its elliptical orbit to influence tides as significantly as we saw in the horrific tsunami last week.

How Many Planets Could Support Life in the Milky Way?

Astronomers have recently estimated that there are 50 billion planets and 300 billion stars in our galaxy, the Milky Way.  With the Kepler Mission, scientists have been able to identify exoplanets in the Milky Way and so far have identified 1,235 planets.  Based on this information, Kepler Science Chief William Borucki has said that they have extrapolated from that data that there are 50 billion planets.  Scientist believe that of these 50 billion planets, 500 million could be located in the “habitable zone” of their stars, meaning that they could support life. 

How much is 500 million?  If you took 500 million 3^rd graders and placed them touching finger-tip to finger-tip, those kids would make 50 and half circles around the Earth¹.  500 million is an awful lot of planets that could potentially support life! 

1)    Assumes each 3^rd grader has an average arm span of 52 inches.  Five hundred million kids touching finger-tip to finger-tip would reach 26,000,000,000 inches.  The Earth has a diameter of 7,926.41 miles or 504,357,468 inches.  26,000,000,000 inches divided by 504,357,468 inches is 51.55 times.

Space Shuttle Discovery’s Final Mission

On February 24^th, Spaceship Discovery started its final mission, STS 133.  (Click here to see a video of the launch.)  Discovery has six crew members on board and the purpose of the mission is to dock with the International Space Station and deliver a module which is essentially additional rooms to be used for lab and storage space. 

Discovery has flown into space more than any other spacecraft.  It is one of five shuttles used by NASA which also included Challenger, Columbia, Atlantis, and Endeavour.  Discovery first launched in 1984.  Since that time, it has made 38 missions, circled the Earth 5,628 times and has taken 246 astronauts into space.  It has traveled 143 million (143,000,000) miles.  It has spent almost an entire year in space.  Now it is time for Discovery to retire.  NASA has created a video of great video of Discovery’s history, please click here.

A Spaceship With a Sail?

NASA has designed a spacecraft that moves through space with a solar sail.  Picture an unmanned spacecraft with a rectangular gold metallic sail that is 100 feet square.  Photons from the sun moving through space hit the sail and move the spacecraft.  NASA launched the NanoSail-D and deployed its sail over the U.S. in low orbit in January.  Here is a link with a great picture of what the spacecraft probably looks like.

Through March 7^th, the spacecraft moving through space can be seen with the naked eye (no telescope needed)!  To help you see NanoSail-D, NASA has partnered with SpaceWeather.com to provide tracking maps (click here) so you know when to look up in the sky.  In Chicago, we will be looking north/northwest at 6:30 pm today.  SpaceWeather.com is hosting a photo competition with prizes up to $500.  Go to http://www.nanosail.org/ to learn more about the contest.

A meteorite will (probably) hit earth today

Each year, thousands of meteorites hit earth. Meteorites are parts of asteroids that have broken off or dust from comets.  Most are so small that we don’t even see them. Others fall in places that we cannot find them, like in the oceans.  A scientist at Washington University in St. Louis has compiled a map of the US showing the number of meteorites found in each state.  Click here to see how many have been found in your state.  In Arizona, there is a crater named Meteor Crater – it was caused when a meteor hit Earth 20,000 to 30,000 years ago.  It is as big as 20 football fields!  (Click here for a video.)

As previously stated, most meteorites are very small and do little damage.  In modern times, no person has been killed by a meteorite.  One of the most significant meteorites to enter earths’ atmosphere in modern times landed in Siberia, Russia in 1908.  It destroyed hundreds of square miles of forest. 

Jupiter has how many moons?!?

Jupiter has 63 moons!  Some are very small and others are larger than Pluto.  The four largest moons are called the Galilean moons because they were discovered by Galileo Galilei in the year 1610.  Ganymede is the largest moon and it is bigger than Mercury.  It is the ninth largest object in our solar system.  The other three Galilean moons are Io, Europa, and Callisto and all are larger than Pluto.  The 59 smaller moons tend to be less than 160 miles in diameter.  Some of these smaller moons have irregular (non-spherical) shapes and astronomers theorize that they have originated from passing asteroids that were pulled into Jupiter’s’ orbit by gravity. 

In February 2007, NASA’s New Horizons spacecraft flew near Jupiter and took pictures of Ganymede, Io, Europa and Callisto.    Click here to see those pictures.

Black Holes and Oreo Cookies

When I was an undergrad at the University of Chicago, I had the opportunity to join a small gathering one evening listening to Nobel Prize winner Subrahmanyan Chandrasekhar.  We students all sat on the floor while Professor Chandrasekhar sat on a sunken couch with his knees up to his chest.  He looked terribly uncomfortable.  Someone passed a plate of Oreo cookies to him and before he could take a bite, we began peppering him with questions about black holes.  The poor man spent the next two hours explaining black holes, having to use the Oreo as an example of a black hole in space.

A black hole is a region of space where gravity pulls so much that nothing, not even light, can escape.  The gravity is strong because matter has been squeezed into a small space.  This can happen because a star implodes, or falls in on itself, when it is dying.    Other black holes formed when the universe began.  Black holes will pull objects into them including comets, stellar gases, planets and even other stars.  During the evening, Professor Chandrasekhar frequently used the cookie to represent a black hole and showed how celestial bodies would disappear into the Oreo.

Today, NASA.gov has great videos and articles on black holes so no cookies needed!  Click here to go to NASA.gov to see a great video on the formation of birth of a black hole.

Why isn't Pluto a planet anymore?

When I was a kid, Pluto was a planet, the smallest planet in our solar system.  But in 2006, the International Astronomical Union (IAU) determined that Pluto is not really a planet, but a dwarf planet.  A dwarf planet is a celestial body that 1) is in orbit around the sun, 2) keeps a nearly round shape, 3) hasn’t cleared the neighborhood around its orbit and 4) is not a satellite.  Pluto was determined to be a dwarf planet because it “hasn’t cleared the neighborhood” around its orbit meaning that there are other celestial objects in its orbital path around the sun. 

Pluto is actually part of the Kuiper Belt.  The Kuiper Belt is in the solar system extending beyond Neptune and it is made up of frozen objects made up of methane, ammonia and water.  Pluto is the largest dwarf planet in the Kuiper Belt.  The two other dwarf planets in the Kuiper Belt are Haumea and Makemake.

NASA has sent a spacecraft to visit Pluto and the Kuiper Belt called New Horizons.  New Horizons left Earth in January 2006 and is not expected to reach Pluto until 2015.

Click here to see NASA’s homepage for Pluto.

The Sun in 3D (no glasses needed)

This week NASA released the first pictures of our sun in 3D.  Back in 2006, NASA sent into space two probes called STEREO probes and now those satellites are in place orbiting the sun and sending images back to Earth in Stereo.  Click here to see a link of the Sun in 3D.

The STEREO probes (called A and B) are located 180 degrees apart on essentially on either sides of the sun.  With the 3D view o the sun, scientists can better monitor solar flares and predict the path -of solar storms.  For example, in August 2010, scientists observed a massive solar storm – link here to see the solar storm.  If the STEREO mission had been in place at that time, scientists could have better observed the path of the storm around the sun.

Do you know what planet in our solar system is not named after an ancient Greek or Roman god?

Earth!

Mercury is the Greek god that is the messenger of Zeus.  The god Mercury is often shown with wings on his shoes so he can fly fast.  If you saw the movie Percy Jackson & the Olympians: The Lightening Thief, Percy used a pair of Mercury’s hightops with wings to fly.

Venus is the Roman goddess of beauty.  Venus is easy planet to see in the sky - it is very bright.

Mars is the Roman god of war.  

Jupiter is the Roman name for the Greek god Zeus.  Zeus was the king of all the Greek gods.  The biggest planet in our solar system is named after the most powerful god.

Saturn is the Roman god of time.

Uranus is the grandfather of Zeus (Jupiter).

Neptune is a Roman god also know as Poseidon, the god of the sea.  Neptune is blue, - it looks like the water on earth.

Pluto (which is no longer a planet, but a dwarf planet) is a god also known as Hades, the king of the underworld.

Space.com is a great website to learn generally about space.  Another fun site specifically for kids is KidsCosmos.com.

NASA’s Kepler Mission Discovers Its First Rocky Planet: Kepler-10b

In January, NASA announced that Kepler has found its first rocky planet which they named “Kepler-10b”.  This is really exciting news because this is the first time we have discovered a rocky planet orbiting a sun other than ours.  Other planets that have been discovered have been gas planets, like Jupiter.  Kepler-10b cannot support life because it is too close to its sun (called Kepler 10).  In fact, Kepler-10b is 20 times closer to its sun that Mercury is to our sun.  Thus, Kepler-10b is not in the “habitable zone” meaning that It is too hot for water and therefore it is unlikely that life can be found on this planet.  Kepler-10b has a very fast year - it orbits its sun in .84 days!  Click this link to see a video on NASA about the discovery: Kepler-10b Discovery.

Is there life on other planets?

Maybe.  NASA is working to find out.

In March 2009, NASA launched the Kepler Mission on Discovery Mission #10 with the goal of finding other Earth-like planets in the universe.   Kepler is an unmanned space observatory that monitors over 145,000 stars (remember, our sun is a star) and provides data to determine if there are life-supporting planets orbiting those stars.  Planets outside of our solar system are called “exoplanets”. 

Kepler finds exoplanets by watching stars.  As you know, stars give off light.  Kepler watches the stars to see if there is a disturbance, or flicker in the light.  If that flicker happens repeatedly at regular times, Kepler has discovered a planet.   This link is an interactive tool for kids to learn how Kepler is spotting planets:  Kepler Exoplanet Transit Hunt.  Check out the Kepler: A Search for Habitable Planets for more some great information from NASA.

There is a great app for the IPhone and IPad called “Exoplanet” which is a daily updated database of all discovered exoplanets.