History is Made: New Horizons Skims Past Pluto

By Tom Yulsman | July 14, 2015 10:26 am

This is the last image taken by NASA’s New Horizon’s spacecraft before it made its closest approach to Pluto. The piano-sized probe was speeding toward the planet at 30,000 miles per hour and was 476,000 miles away. (Source: NASA)

| JUST RELEASED (7/15/15): The First Incredible Closeup Image of Pluto Reveals Gigantic Ice Mountains |

After a journey of 10 years and three billion miles, NASA’s New Horizons spacecraft has made its closest approach to Pluto.

I’m not saying “successfully” because we don’t yet know how well the spacecraft has fared during its close encounter. We’ll know by about 9 p.m. EDT when New Horizons is supposed to phone home.

But scientists do know that the piano-sized probe skimmed just 7,750 miles above the surface of the far away world at 7:49 EDT today — as planned — and is now speeding ever outward into the icy Kuiper Belt.

When I say speeding, I mean it: At closest approach, New Horizons was zipping along at 30,000 miles per hour, making it the fastest spacecraft ever launched.

To appreciate what a remarkable achievement New Horizons’ close encounter with Pluto truly was, consider this, from NASA:

New Horizons’ almost 10-year, three-billion-mile journey to closest approach at Pluto took about one minute less than predicted when the craft was launched in January 2006. The spacecraft threaded the needle through a 36-by-57 mile (60 by 90 kilometers) window in space — the equivalent of a commercial airliner arriving no more off target than the width of a tennis ball.

When New Horizons reestablishes contact tonight, it is scheduled to begin sending a trove of scientific data back to Earth — 10 year’s worth. That’s so much that it will take 16 months to complete the data transfer!

Then on Wednesday afternoon, NASA should release processed images taken during the spacecraft’s closest approach.

As we wait for New Horizons to reestablish contact tonight, we can enjoy the spectacular close-up image it snapped of Pluto when it was 476,000 miles from the surface. It was the final image sent back before the spacecraft made its closest approach.

The rusty tones come from low resolution color information acquired by an instrument called Ralph (the name is a reference to the Honeymooners television show).  Here is NASA’s description of what you’re seeing:

This view is dominated by the large, bright feature informally named the “heart,” which measures approximately 1,000 miles (1,600 kilometers) across. The heart borders darker equatorial terrains, and the mottled terrain to its east (right) are complex. However, even at this resolution, much of the heart’s interior appears remarkably featureless—possibly a sign of ongoing geologic processes.

With New Horizons’ close encounter with Pluto, the reconnaissance of the classical solar system — Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune and now Pluto — is complete.

CATEGORIZED UNDER: Astronomy, Planetary Science
  • Mike Richardson

    Some of the earlier conjectures about Pluto appear correct, such as the reddish color and the possibility of nitrogen snow/ice, which might explain the heart. Some of the rougher terrain does resemble Neptune’s moon Triton, which is suspected of being a captured Kuiper belt object similar to Pluto, since it has a retrograde orbit. It might be a bit early to tell about any cryovulcanism from the current images, but the next few days could reveal whether or not it has that in common with Triton, too. As for our survey of the classical solar system ending, the good news is, there are billions of others out there to study!

    • Bobareeno

      If you don’t mind the 4+ year long wait for the data and images. Of course one assumes the technology will have advanced…… to the point of time and space warping causing the information to arrive in the Money Pit timeline (2 weeks.)

      • Mike Richardson

        I’d love to see some kind of shortcut around special relativity, but alas, it doesn’t look like Charon’s a mass relay, and most of the theories for space warps involve using a significant portion of the energy of a star. Wormholes seem to require exotic negative material as yet undiscovered to keep them from collapsing. So we might be in for a wait from any probes sent to nearby stars. In the meantime, though, the Kepler space telescope is still giving us a census of some of the other planetary systems out there, and the James Webb telescope (as well as any successors to Kepler) promise better long distance views. Also, the next generation of very large telescopes here on Earth seeing first light in the coming decade should also get us closer to finding the first truly earthlike planets. As for New Horizons itself, NASA is already working on one or two other Kuiper belt objects for it to fly past on the way out of the solar system.

        • Bobareeno

          Thank you Mike…you turned my silly suggestion back into a serious topic. Kudos to your robust analysis.

          • Mike Richardson

            You’re quite welcome. If you’d like a more detailed discussion of the telescopic surveys of other solar systems, go check out the Crux blog
            article “How Astronomers Will Find Earth 2.0,” posted just yesterday. For more information about possible methods of conducting interstellar surveys, you might want to check out Paul Gilster’s blog, Centauri Dreams: http://www.centauri-dreams.org. It’s one I’ve got saved as a favorite.



ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.

About Tom Yulsman

Tom Yulsman is Director of the Center for Environmental Journalism and a Professor of Journalism at the University of Colorado, Boulder. He also continues to work as a science and environmental journalist with more than 30 years of experience producing content for major publications. His work has appeared in the New York Times, Washington Post, Audubon, Climate Central, Columbia Journalism Review, Discover, Nieman Reports, and many other publications. He has held a variety of editorial positions over the years, including a stint as editor-in-chief of Earth magazine. Yulsman has written one book: Origins: the Quest for Our Cosmic Roots, published by the Institute of Physics in 2003.


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