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In order to better serve Earth and space science teachers, we have prepared an anonymous survey to gather information about your Earth and space science education needs and concerns, your satisfaction with Windows to the Universe and this newsletter, and your ideas about how we can serve you better. We have 801 responses so far, but would love to have more! Please take a moment to complete this survey at your earliest convenience, if you haven't already. You may receive notice about this survey from a variety of sources, but please be sure to only complete the survey once! Thanks so much for your time and effort!
Summer is Here!?
Summer is here! Or so it seems on the calendar at least. Here in Boulder, Colorado, the weather has been quite cool and rainy, relative to the climatological averages for the Spring. As a result, many plants seem to be late with their first blooms, including the peonies in my backyard!
This brings to mind the difference between weather and climate. A wise middle school student once made the following observation - "Climate determines what clothes I buy, and weather determines the clothes I wear". Climate at any location is the long-term average of weather conditions, typically over 30 years, and is related to the location's latitude, altitude, proximity to geographic barriers, and position on a continent (by the ocean or inland). Weather is the day-to-day variation in temperature, precipitation, humidity, and winds that sets the tone for each day (and determines our choice in clothing)!
Sometimes, a continued period of cool or warm weather over several weeks makes us think that something odd is happening with the weather. For a prolonged period of different weather conditions to have an impact on climate, they would need to persist for years (on average). Scientists typically don't associate any particular weather event with climate change - because weather is too transient. Instead, they look at the long-term averages of temperature and precipitation, among other factors. And when they look at these averages, they do, indeed, see that our climate is changing over the long run.
Many of you have been watching the Mississippi river this past month as it rose to historic high levels and caused major flooding all along its path through the U.S.. In April, two major storm systems produced a huge amount of rainfall on the Mississippi basin, which resulted in very high water levels by early May. The river was already rising from springtime snowmelt, and the extra rain led to floods in Illinois, Missouri, Kentucky, Tennessee, Arkansas, Mississippi, and Louisiana. The flooding was so bad that for the first time since the 1970's, the Morganza Spillway in Louisiana was opened in order to divert large amounts of water that were threatening Baton Rouge and New Orleans (the water was diverted to rural Louisiana, where it flooded several thousand square miles of farmland). Our thoughts go out to all of those affected by the floods.
This might be a good time to teach students about floods. Teaching about how floods happen, the different types of floods (such as flash floods which occur in only a few hours and are usually characterized by raging currents of water), and the difference between flood warnings and advisories will help them understand more about weather and climate and also prepare them for potential weather emergencies.
Read more about how floods arise and what can cause them at FloodSmart.gov.
Learn about Tornadoes!
Although tornadoes can happen at any time of the year, they are especially common during the spring and early summer. May and June are usually the peak months in terms of numbers of tornadoes in the northern hemisphere. In 2011, April saw the unfortunate outbreak of many tornadoes across the U.S. On May 22nd, an EF-5 tornado tore through Joplin, MO, injuring more than 900 people and killing at least 142 people. This makes it the nation's single-deadliest tornado in six decades. Remember to visit redcross.org now to see how you can help those affected by these recent tornadoes.
The conditions that lead to the formation of tornadoes are most often met in the central and southern U.S., where warm, humid air from the Gulf of Mexico collides with cool, dry air from the Rockies and Canada. The area where tornadoes occur most often extends roughly from the Rocky Mountains to the Appalachians, and from Iowa and Nebraska to the Gulf of Mexico. The center of this area, which includes parts of Texas, Oklahoma, Kansas, and Nebraska, is often called tornado alley. Tornadoes can also occur elsewhere though, including all U.S. states, Europe, Asia, and Australia.
The weather section of Windows to the Universe provides information about these storms, including how tornadoes form, how meteorologists forecast where and when tornadoes will occur, and how scientists use the Enhanced Fujita Scale to determine the strength of a tornado. In addition, our Tornado in a Bottle classroom activity provides a great way to illustrate tornadoes for your students.
The Most Volcanic Object in the Solar System
New data analysis from NASA's Galileo spacecraft reveals a subsurface ocean of molten or partially molten magma beneath the surface of Jupiter's volcanic moon Io. The finding heralds the first direct confirmation of this kind of magma layer at Io and explains why the moon is the most volcanic object known in the solar system.
Io produces about 100 times more lava each year than all the volcanoes on Earth. While Earth's volcanoes occur in localized hotspots like the "Ring of Fire" around the Pacific Ocean, Io's volcanoes are distributed all over its surface. A global magma ocean about 20 to 30 miles (30 to 50 kilometers) beneath Io's crust helps explain the moon's activity.
NASA's Voyager spacecraft discovered Io's volcanoes in 1979. The energy for the volcanic activity comes from the squeezing and stretching of the moon by Jupiter's gravity as Io orbits the largest planet in the solar system.
Galileo was launched in 1989 and began orbiting Jupiter in 1995.. After a successful mission, the spacecraft was intentionally sent into Jupiter's atmosphere in 2003.
Eratosthenes Measured Our World
Eratosthenes, an ancient Greek scientist, made the first accurate measurement of the size of the Earth in 240 B.C. June 19th will be 2250th anniversary of this event (remember there was no year 0!). He knew that the Sun made no shadow in a well in the Egyptian town of Syene on the summer solstice; and therefore, that the Sun must be directly overhead in Syene on that day. He measured the length of the shadow of a tall tower in his hometown of Alexandria on the solstice. He combined this information with the distance between Alexandria and Syene (about 800 km), and with a little geometry, was able to determine the circumference of the Earth with surprising accuracy for that time.
Eratosthenes was a mathematician, elegiac poet, athlete, geographer, astronomer, music theorist, a friend of Archimedes and a chief librarian of the famous Alexandrian library. He proposed a simple algorithm for finding prime numbers, known in mathematics as the Sieve of Eratosthenes. He made other major contributions to mathematics, geography and astronomy. Surprisingly, his contemporaries nicknamed him beta, from the second letter of the Greek alphabet, because he supposedly proved himself to be the second best in almost every field.
Warming of Large Lakes - Video and Classroom Activity
Many of us will be vacationing during this upcoming break. Lakes are a great place to visit on family vacation. Did you know that scientists have found a global warming trend in large lakes? Now warmer water to swim in might sounds like a good thing, but like other effects of global warming, the warming of large lakes could have undesirable implications. We sure hope you don't find these on your travels, but these effects are something to be aware of for yourself and your students.
Scientists are just starting to study and understand the implications of rising temperatures on lake ecosystems. One area of concern is the fact that rising lake temperatures result in increased algal blooms. Algae are naturally found in lake ecosystems and are in fact the base of the aquatic food web. But when the numbers of algae in a lake rise dramatically, a bloom results. Some algal blooms are harmless to life, but are simply unappealing. Water in that area might look terrible, smell foul or even taste bad (when water is drawn for drinking and purification from that source). Other times, algal blooms can be toxic to fish, other aquatic organisms, wild and domestic animals that use that source of water, and humans. Humans can experience gastroenteritis (if the toxin is ingested), lung irritations (if the toxin becomes aerosolized) or skin irritation (if the algae/toxin is touched for instance while swimming).
Rising lake temperatures have also been shown to favor invasive species found in lakes. In the Great Lakes region, two examples of invasive species under scrutiny are zebra mussels and lampreys. Zebra mussels have been seen to thrive in warmer and warmer waters, which means they can extend their living range to higher and higher latitudes. Lampreys seem to thrive in warmer waters growing bigger and bigger and are staying active for more of the year. Both of these invasive species are extreme pests that are killing off native species, eating the food of native species, or in the case of zebra mussels, causing billions of dollars of damage to structures and aquatic vehicles.
Clearly, more study and attention is due these important limnic ecosystems where so many people live, work, make their homes, and enjoy recreation and relaxation.
To learn more, explore our Warming Lakes Classroom Activity or watch a video produced by NBC Learn called Warming Lakes.
Endeavour's Final Flight
The final launch of space shuttle Endeavour occurred on May 16, 2011.. The shuttle's first landing opportunity at Kennedy is scheduled for 2:32 a.m. on June 1. STS-134 is the 134th shuttle flight, the 25th flight for Endeavour and the 36th shuttle mission dedicated to station assembly and maintenance.
Endeavour's crewmembers were Commander Mark Kelly, Pilot Greg H. Johnson and NASA Mission Specialists Mike Fincke, Drew Feustel and Greg Chamitoff and European Space Agency Mission Specialist Roberto Vittori. Crewmembers executed four spacewalks to do ISS maintenance work, installed new components, and performed a complex series of tasks to top off the ammonia in one of the station's photovoltaic thermal control system cooling loops. Endeavour also made important deliveries to the ISS.
As Endeavour's flight concludes, the NASA blog will detail the spacecraft's return to Earth. For NASA's launch blog and mission highlights, visit: http://www.nasa.gov/shuttle
Solstice is Coming!
The solstice occurs this month on June 21. The solstices (summer and winter) and equinoxes (spring and fall) are astronomical events that mark our seasons. Because of the tilt of Earth's axis, the Sun appears to climb higher (in the summer) and sink lower (in the winter) in the sky as viewed from our planet. A solstice is a time when the Sun momentarily pauses in this apparent migration as it reaches the greatest extremes of its "wanderings" and begins to "move" back in the opposite direction. The word "solstice" comes from two Latin roots: "sol", which means "Sun", and "sistere", which translates as "stand still".
The June solstice is the summer solstice in the Northern Hemisphere. The situation is, of course, reversed in the Southern Hemisphere - where the June solstice is the winter solstice. The solstice is commonly referred to as the start of summer (or winter), but it is actually the midway point of the season from an astronomical perspective. Since our planet's atmosphere and oceans "store" heat, temperature extremes tend to lag behind the dates of minimum (or maximum) heating by the Sun, so the coldest part of winter (or hottest part of summer) happens after the solstice.
Students often mistakenly believe that the seasons are caused by variations in Earth's distance from the Sun. This misconception doesn't make sense when one remembers that the seasons are opposite in the Northern and Southern Hemispheres - why isn't it cold everywhere on the globe when the Earth is farthest from the Sun? As Earth travels around the Sun in its elliptical orbit, its closest approach to our celestial furnace is in January, during the depth of winter in the Northern Hemisphere.
To learn more about the solstice and seasons, check out these pages on Windows to the Universe:
What Causes the Seasons?
Earth's Tilt Is the Reason for the Seasons!
The Seasonal Merry-Go-Round
The Four Seasons