Earth seems to be pretty special when it comes to life. Life is everywhere on the surface of our planet. It can even be found deep underground and high in the sky. As our exploration has continued around the globe, we are finding life in nearly every possible environment. Many of these environments are not very suitable for humans. In some cases, they may even be really dangerous for us. For instance, the organisms known as “extremophiles” are called that because they live in places that are too extreme for humans. These can be places like hot springs and hydrothermal vents, deep under the ocean or inside of glaciers, in deserts or even in fluids that are as acidic as battery acid. Finding life in so many places on Earth tells us that there are a lot of conditions that life can survive in. But what about other worlds? Earth is currently the only place we know of that has life, but do you think we might find some of those conditions for life in other places?
The planet Mars today is very cold, it doesn’t have a thick atmosphere, and there’s no flowing water on the surface. Long ago, Mars had rivers and lakes and maybe even an ocean of water at the surface. It had a denser atmosphere than it does today and lots of active volcanoes. Ancient Mars had the chemical ingredients for life, there was energy (solar, geothermal, and possibly chemical), and plenty of water. Many microorganisms on Earth today could have survived and likely even thrived in early Martian conditions. Maybe some things like our extremophiles on Earth were the last survivors of some Martian life that thrived there long ago. There are many people who are studying whether we could find signs of that ancient life on Mars if it ever existed there.
And there are other places where we are looking for potential signs of past or even present alien life. The moons Europa and Enceladus are really interesting to study, for instance. Europa is a moon of Jupiter and Enceladus is a moon of Saturn, and we now have evidence that both of these moons have oceans of liquid water underneath of their icy crusts. How can these moons have liquid water? Both are way too far from the Sun for it to give enough energy to melt them, and their oceans are below their icy crusts. It turns out that the way that these moons interact with their larger planets, through the action of gravity, causes them to heat up inside. This internal energy not only is enough to cause them to have liquid water oceans, but might also cause them to have hydrothermal vents on their ocean floors. Because of this possibility, many of us wonder if there could be living biospheres inside of the oceans of those icy moons.
Almost every star has planets orbiting it. Now that we know that there are many planets out there, we’re really wondering if we might one day soon find other worlds that are not only about the size of Earth and roughly the same distance from their stars, but that might also have biospheres that may be something like ours. We’re building better and better telescopes so that we can study those worlds when we find them to figure out if we can find signs of life on them. It’s a very interesting time to be alive when it comes to learning about whether or not we are alone in the universe.
Disciplinary Core Ideas
LS2.A: Interdependent Relationships in Ecosystems: Organisms, and populations of organisms, are dependent on their environmental interactions both with other living things and with nonliving factors. (MS-LS2-1) ▪ In any ecosystem, organisms and populations with similar requirements for food, water, oxygen, or other resources may compete with each other for limited resources, access to which consequently constrains their growth and reproduction. (MS-LS2-1) ▪ Growth of organisms and population increases are limited by access to resources. (MS-LS2-1, MS-LS2-2)
LS2.C: Ecosystem Dynamics, Functioning, and Resilience: Ecosystems are dynamic in nature; their characteristics can vary over time. Disruptions to any physical or biological component of an ecosystem can lead to shifts in all its populations. (MS-LS2-4)
LS4.C: Adaptation: Adaptation by natural selection acting over generations is one important process by which species change over time in response to changes in environmental conditions. Traits that support successful survival and reproduction in the new environment become more common; those that do not become less common. Thus, the distribution of traits in a population changes. (MS-LS4-6)
ESS1.A: The Universe and Its Stars: Patterns of the apparent motion of the Sun, the Moon, and stars in the sky can be observed, described, predicted, and explained with models. (MS-ESS1-1) ▪ Earth and its solar system are part of the Milky Way galaxy, which is one of many galaxies in the universe. (MS-ESS1-2)
ESS1.B: Earth and the Solar System: The solar system consists of the Sun and a collection of objects, including planets, their moons, and asteroids that are held in orbit around the Sun by its gravitational pull on them. (MS-ESS1-2, MS-ESS1-3) ▪ This model of the solar system can explain eclipses of the Sun and the Moon. Earth’s spin axis is fixed in direction over the short-term but tilted relative to its orbit around the Sun. The seasons are a result of that tilt and are caused by the differential intensity of sunlight on different areas of Earth across the year. (MS-ESS1-1) ▪ The solar system appears to have formed from a disk of dust and gas, drawn together by gravity. (MS-ESS1-2)
Scientific Knowledge Assumes an Order and Consistency in Natural Systems: Science assumes that objects and events in natural systems occur in consistent patterns that are understandable through measurement and observation. (MS-ESS1-1, MS-ESS1-2)
2-5, 6-8 Mystery Planet. In this lesson (90 minutes), students use samples of crustal material to sort, classify, and make observations about an unknown planet. In this 5E activity, students step into the shoes of real planetary scientists. From their observations, students interpret the geologic history of their mystery planet. Arizona State University/NASA. http://marsed.asu.edu/mystery-planet
4-12 Finding Life beyond Earth, Activity 6: Where to Look for Life (page 29). Students examine environment cards that describe planets and moons in terms of their temperature and atmosphere and the availability of water, energy, and nutrients. They then select the best candidates to search for life. https://d43fweuh3sg51.cloudfront.net/media/assets/wgbh/nvfl/nvfl_doc_collection/nvfl_doc_collection.pdf
5-8 Astrobiology in Your Classroom: Life on Earth…and Elsewhere. Activity 5: Is there life on other worlds? Page 49. In activity 5, students consider the possibility of life—simple and technological—in our galaxy by looking at the size and composition of our galaxy. Using the Drake Equation, students identify what information they would need to determine the probability of extraterrestrial life. NASA. https://nai.nasa.gov/media/medialibrary/2013/10/Astrobiology-Educator-Guide-2007.pdf
5-8 Astrobiology in Your Classroom: Life on Earth…and Elsewhere. Activity 4: What can life tolerate? Page 37. In activity 4, students identify the range of terrestrial life. The activity includes matching extremophiles to their habitat and debating the ethics of sending Earth life to other worlds. NASA. https://nai.nasa.gov/media/medialibrary/2013/10/Astrobiology-Educator-Guide-2007.pdf
6-8 SpaceMath Problem 61: Drake’s Equation and the Search for Life…sort of! In this simplified version, your students get to review what we now know about the planetary universe, and come up with their own estimates. The real fun is in doing the research to track down plausible values (or their ranges) for the factors that enter into the equation, and then write a defense for the values that they choose. Lots of opportunity to summarize basic astronomical knowledge towards the end of an astronomy course, or chapter. [Topics: decimal math; evaluating functions for given values of variables] https://spacemath.gsfc.nasa.gov/astrob/2page18.pdf
6-8 SpaceMath Problem 391: Investigating the atmosphere of Super-Earth GJ-1214b. Students investigate a simple model for the interior of an exoplanet to estimate the thickness of its atmosphere given the mass size and density of the planet. [Topics: graphing functions; evaluating functions for given values; volume of a sphere; mass = density x volume] https://spacemath.gsfc.nasa.gov/astrob/7Page55.pdf
6-8 SpaceMath Problem 335: Methane Lakes on Titan. Students use a recent Cassini radar image of the surface of Titan to estimate how much methane is present in the lakes that fill the image, and compare the volume to that of the freshwater lake, Lake Tahoe. [Topics: estimating irregular areas; calculating volume from area x height; scaled images] https://spacemath.gsfc.nasa.gov/planets/6Page148.pdf
6-8 SpaceMath Problem 403: The Goldilocks Planets – Not too hot or cold. Students use a table of the planets discovered by the Kepler satellite, and estimate the number of planets in our Milky Way galaxy that are about the same size as Earth and located in their Habitable Zones. They estimate the average temperature of the planets, and study their tabulated properties using histograms. [Topics: averaging; histogramming] https://spacemath.gsfc.nasa.gov/astrob/7Page66.pdf
6-9 Project Spectra: Planet Designer: Martian Makeover. This is an activity (two 50-minute lessons) about the atmospheric conditions (greenhouse strength, atmospheric thickness) Mars needs to maintain surface water. Learners use a computer interactive to learn about Mars past and present before exploring the pressure and greenhouse strength needed for Mars to have a watery surface as it had in the past. This lesson is part of Project Spectra, a science and engineering education program focusing on how light is used to explore the Solar System. University of Colorado, Boulder/NASA. http://lasp.colorado.edu/home/wp-content/uploads/2013/06/martian_makeover_teacher_20130617.pdfhttp://lasp.colorado.edu/home/education/k-12/project-spectra/
6-12 (3-5 adaptable) Project Spectra! – Goldilocks and the Three Planets. In this lesson (two class periods), students determine what some of Earth, Venus, and Mars’ atmosphere is composed of and then mathematically compare the amount of greenhouse gas and CO2 on the planets of Venus, Earth, and Mars, in order to determine which has the most. Students brainstorm to figure out what things, along with greenhouse gases, can affect a planet’s temperature which can determine its habitability. University of Colorado, Boulder/NASA. http://lasp.colorado.edu/home/wp-content/uploads/2011/08/Goldilocks.pdf
6-12 (3-5 adaptable) Project Spectra! Using Spectral Data to Explore Saturn and Titan. In this lesson students compare known elemental spectra with spectra of Titan and Saturn’s rings from a spectrometer aboard the NASA Cassini spacecraft. Titan is one of the most interesting planetary bodies in the search for life beyond Earth. Students identify the elements visible in the planetary and lunar spectra. University of Colorado, Boulder/NASA. http://lasp.colorado.edu/home/wp-content/uploads/2011/08/Using_Spectral_Data.pdf
6-12 (3-5 adaptable) Project Spectra! – Marvelous Martian Mineralology. In the Marvelous Martian Mineralogy lesson, students use reflectometers to determine which minerals are present (from a set of knowns) in a sample of Mars soil simulant. This rich activity can be done with data only, with ALTA ii reflectometers and real mineral samples or with computer simulation. Identifying minerals through spectrometry is a powerful tool in the search for life and the conditions for life in the solar system and beyond. University of Colorado, Boulder/NASA. http://lasp.colorado.edu/home/wp-content/uploads/2011/08/Marvelous_Martian_Mineralogy.pdf
6-12 (3-5 adaptable) Project Spectra! – Star Light, Star Bright? Finding Remote Atmospheres. Students explore stellar occultation events to determine if an imaginary dwarf planet “Snorkzat” has an atmosphere. Characterizing planetary bodies through spectrometry is a powerful tool in the search for life and the conditions for life in the solar system and beyond. University of Colorado, Boulder/NASA. http://lasp.colorado.edu/home/wp-content/uploads/2011/10/starlight_starbright_teacher.pdf
6-12 (3-5 adaptable) Project Spectra! – Enceladus, I Barely Knew You. In this activity, students establish whether Saturn’s small moon Enceladus has an atmosphere, whether the atmosphere encircles the whole moon, and whether it contributed to Saturn’s E-ring. Through data analysis students hypothesize attributes of Enceladus, a planet that has evidence of a water ocean under its icy crust. Characterizing planetary bodies through spectrometry is a powerful tool in the search for life and the conditions for life in the solar system and beyond. University of Colorado, Boulder/NASA. http://lasp.colorado.edu/home/wp-content/uploads/2011/10/Enceladus_knewyou_teacher.pdf
6-12 (3-5 adaptable) Project Spectra! – Planet Designer: What’s Trending Hot? This is a collection of 17 lessons ranging from 30 minutes to multi-week projects. In the activity (two 50-minute lessons) Planet Designer: “What’s Trending Hot?” students use a computer game format of a featureless planet to deduce what variables affect the temperature of the planet. They control the distance to the Sun, Albedo, Density, size and greenhouse gases. Using computer simulation is a powerful tool in the search for life and the conditions for life in the solar system and beyond. University of Colorado, Boulder/NASA. http://lasp.colorado.edu/home/wp-content/uploads/2013/06/TrendingHot_teacher_20130617.pdf
6-12 (3-5 adaptable) Project Spectra! – Planet Designer: Kelvin Climb? Students create a planet using a computer game and change features of the planet to increase or decrease the planet’s temperature. Students explore some of the same principles scientists use to determine how likely it is for a planet to maintain flowing water, a critical ingredient for life as we know it. Using computer simulation is a powerful tool in the search for life and the conditions for life in the solar system and beyond. University of Colorado, Boulder/NASA. http://lasp.colorado.edu/home/wp-content/uploads/2013/06/KelvinClimb_teacher_20130617.pdf
6-12 (3-5 adaptable) Project Spectra! – Planet Designer: Retro Planet Red. In this lesson, students learn about Mars’ past and present before exploring the pressure and greenhouse strength needed for Mars to have a watery surface as it had in the past. Water is a key ingredient for life. University of Colorado, Boulder/NASA. http://lasp.colorado.edu/home/education/k-12/project-spectra/
6-8 or 9-12 Question Mars. This three-hour standalone lesson is part of an exploration unit in Mars Student Imaging Project (MSIP). Students act as planetary geologists and learn about how to identify the geologic history of Mars with an eye toward its habitability. Students mirror the actions of planetary scientists as they follow their curiosity in order to create a researchable question that can be investigated through real scientific data/images. Arizona State University/NASA. http://marsed.asu.edu/msip-question-mars
6-12 Astrobiology Math. This collection of math problems provides an authentic glimpse of modern astrobiology science and engineering issues, often involving actual research data. Students explore concepts in astrobiology through calculations. Relevant topics include Lakes of Methane on Titan (page 53) and Heat Flow Balance and Melting Ice (page 47). NASA. https://www.nasa.gov/pdf/637832main_Astrobiology_Math.pdf
6-12 Science Fiction Stories with Good Astronomy & Physics: A Topical List: Life Elsewhere. The Astronomical Society of the Pacific created this list of short stories and novels that use more or less accurate science and can be used for teaching or reinforcing astronomy or physics concepts including plausible places for life beyond Earth.. https://astrosociety.org/file_download/inline/621a63fc-04d5-4794-8d2b-38e7195056e9
8-10 SpaceMath Problem 292: How Hot is That Planet? Students use a simple function to estimate the temperature of a recently discovered planet called CoRot-7b. [Topics: algebra II; evaluating power functions] https://spacemath.gsfc.nasa.gov/astrob/6Page61.pdf
8-10 SpaceMath Problem 264: Water on Planetary Surfaces. Students work with watts and Joules to study melting ice. [Topics: unit conversion, rates] https://spacemath.gsfc.nasa.gov/astrob/Astro3.pdf