Science Through Backyard Astronomy

With so many of us home or not venturing far from home in these COVID-19 times, it’s a great time to do some local backyard astronomy. And you can contribute to valuable citizen science efforts by submitting your observations to GLOBE at Night. This year’s campaign extends through the entire calendar year, so take advantage of any clear skies, do some observing, and be included in this study of light pollution worldwide!

As of July 2020, citizen scientists from around the world have contributed 20,442 night sky observations to help quantify light pollution around the world. Participating is simple: go outside about one hour after sunset and locate the constellation(s) identified for that month.

August: Cygnus, Hercules
September: Cygnus
October: Cygnus, Pegasus
November: Pegasus, Perseus
December: Perseus

(For star-hunting tips as well as Southern Hemisphere constellations, view the GLOBE at Night website.)

View of Cygnus the Swan in the northern sky, Creative Commons image from Till Credner.

Once you’ve found the constellation in the sky, compare your observation with a brightness magnitude chart, and report your finding along with your latitude and longitude on the website. You can look at the GLOBE at Night results to see how the light pollution of your skies compares with that in other locations around the world.

This year’s observing period continues through December, so visit the website to learn more, get out there and marvel at the stars, and submit your observation to be counted and contribute to learning more about light pollution, both locally and globally.

Simple Math with Oil Spills

A blast from the past! Oil spills and unit conversations, a middle school Practical Uses of Math and Science (PUMAS) example published in 1999.

The short story: On February 4, 1999, the 639-foot freighter New Carissa became grounded near Coos Bay on the Oregon coast. Aboard the ship were 400,000 gallons of bunker fuel, threatening to leak from the fractured hull and damage the state’s fragile beach habitats. With an approaching storm increasing the chances of a disastrous spill, authorities decided to set the ship afire, a choice not without controversy and risks of its own. What would be the potential scale of the disaster if that much oil did spill? 400,000 gallons is equivalent to 400,000 milk jugs –- a lot of milk. But how much space does 400,000 gallons really take up? Some simple arithmetic can help put the quantity in perspective.

See the full article at: https://pumas.gsfc.nasa.gov/files/02_23_99_1.pdf

Melting Snow and Rising Rivers

This map of snow water equivalent shows the amount of water contained in the snowpack–essentially, the depth of water released if the entire snowpack was melted instantaneously.

snow water equivalent

The map comes from the National Operational Hydrologic Remote Sensing Center, which also provides information about snow depth and other snow-related variables.

Snow water equivalent provides useful information for water supply (and things like soil moisture for agriculture and other land uses) as well as for flood forecasting. It’s an important number to watch during the spring months, particularly along the Nebraska-Iowa and North Dakota/South Dakota-Minnesota borders.

In these areas, the snow is melting (at last!). But there’s been a lot of snow over much of the upper midwest this winter, and it’s melting quickly. That can mean lots of surface runoff, especially in areas of deep frost, which can cause localized flooding. Eventually, this runoff makes it into the rivers, where high water levels and potential ice jamming can lead to rivers spilling over banks and levees, resulting in property damage, and in some cases, potential loss of life.

The National Weather Service has a flood safety website to help you learn about the flood danger in your particular area and review safety tips. Understanding the danger as well as the actions you can take will help you be better prepared if or when flooding does occur.

Today’s Instructional Lesson: Seiches

A seiche is an oscillation associated with a standing wave that occurs in an enclosed or partially enclosed body of water, resulting from seismic activity or meteorological effects.

graphic of wind-driven seiche
Click to view this University of Wisconsin Sea Grant Institute animation of a wind-driven seiche. Seiches are not uncommon phenomena on the Great Lakes and adjacent bays and rivers.

Seiches have been observed on lakes, reservoirs, ponds, rivers, and even swimming pools. You can create your own seiche in your bathtub, just by rocking back and forth. At the right frequency, you can set up an oscillation–essentially a small-scale seiche–that allows the waves to grow until they overflow the bath.

A similar “sloshing”–in this case a seismic seiche–was observed on Saturday, February 27, on Lake Pontchartrain in Louisiana, caused by an earthquake 4,700 miles away off the coast of Maule, Chile. Lake Pontchartrain sits on the Mississippi Delta, which contains a deep layer of surface sediments. Seismic waves can resonate through this sediment more easily than through more firm surface types, making the Gulf region particularly sensitive to earthquake-induced seiches. The seiche affecting Lake Pontchartrain occurred 11 minutes after the 8.8 magnitude Chilean earthquake and resulted in water levels about 6 inches higher than the predicted tides.

Want the video version? Derek Kevra at WWLTV has a great explanation of the quake and resulting seiche here. And if you want to learn more about seiches in history, check out this page from the USGS Earthquake Hazards program.