SCIENCE

After almost a decade in flight, New Horizons will fly by the enigmatic dwarf planet on Tuesday. What it will find there is anybody’s guess. (National Geographic magazine)

Play our fun game to learn “Pluto’s Secret” ahead of New Horizons. (Or, make your own paper model of Pluto and the New Horizons spacecraft!)

Teachers, scroll down for a quick list of key resources in our Teachers’ Toolkit.

Note: Current Event Connections is slowing down for the summer. Our column will continue to appear once or twice a week until mid-August. If you have an idea for a Current Event Connection, a recommendation for a good read, or want to share one of your MapMaker Interactive maps, let us know in the comments!

Discussion Ideas

• NASA launched the New Horizons space probe way back in 2006. (Follow its journey with this handy video.) Why has it taken more than 9 years to fly by Pluto? Watch the video above for some help.
  • Pluto is a loooooong way away. Because solar system objects orbit in ellipses and not circles, and Pluto’s orbit is especially weird, the distance between Earth and Pluto is constantly changing. Right now, it’s about 5 billion kilometers (3.1 billion miles) away from Earth.
    • At their closest, perihelion, Earth and Pluto are only 4.4 billion kilometers (2.7 billion miles) apart. Pluto last reached perihelion in 1989.
    • At its most distant, aphelion, the two bodies are on the opposite sides of the sun. At aphelion, Pluto lies 7.5 billion kilometers (4.7 billion miles) from Earth. Pluto will next reach aphelion in 2113. (Mark your calendars!)
  • Just for reference, light itself—the fastest stuff* in the universe—takes 4.4 hours to reach Pluto from Earth. Light takes about 8 minutes to reach Earth from the sun. This means that from Earth, Pluto is 4.4 light-hours away, and the sun is 8 light-minutes away. Remember, these measurements (light-hour, light-year) describe distance, not time.

    • *Would you consider light “stuff”? Probably not. Still, speedy.

• OK, but couldn’t the brain trust at NASA get there faster than 9 years? Why don’t they just make New Horizons travel the speed of light?
  • Well, sure, it could be faster. Two big factors could have sped up New Horizons:
    • New Horizons could have used more powerful rockets. (These are a lot heavier, a lot more complex, and a lot more expensive.) Take a look at the spacecraft’s 2006 takeoff with the plenty-powerful Atlas V 551 rocket.
    • New Horizons could have lightened its load by carrying fewer scientific instruments and equipment. But what would be the point of flying by Pluto if you couldn’t take pretty pictures? (BTW, this is what pretty pictures look like to astrophysicists.)
  • Uh, nothing travels at the speed of light except light. Near light speed, any extra energy you put into an object does not make it move faster. It just increases the object’s mass.

• What is New Horizons going to see when it gets to Pluto?
  • Who knows?! Well, OK, we have some general ideas. Take a look at the images below for three scientifically plausible “Plutoscapes.” (Charon, Pluto’s largest moon, hovers in the distance.)

    

• Top: Tectonically Active.
  • The rugged topography, active geysers, and distant rift suggest Pluto has dynamic geological processes that erase the scars of impact craters and could indicate a warm planetary core.
• Center: Windswept.
  • Strong winds may be generated when ices change state from solid to gas and back again, helping sculpt Pluto’s crust. Eroded peaks remain from ancient impact craters, with water ice forming at the higher elevations. UV radiation strips hydrogen from frozen methane, leaving a swath of dark carbon dust.
• Bottom: Undulating.
  • As Pluto’s ices continually change state by escaping into the atmosphere and condensing back to the surface, they may fill in Pluto’s low-lying areas, smoothing its surface into an undulating terrain. The ices react with sunlight and cosmic radiation at different rates, forming an icy gravel.

TEACHERS’ TOOLKIT (all free, all fun)

Nat Geo: Pluto At Last article

Nat Geo: Pluto’s Secret game

NASA: Design and Build New Horizons model kit

Nat Geo: What is a space probe? activity

Nat Geo: Mission Pluto television series

NASA: New Horizons—NASA’s Mission to Pluto endless information

NASA: New Horizons Twitter

NASA: The Year of Pluto documentary film