It took nearly a decade to travel three billion miles through our solar system, but NASA's New Horizons spacecraft has finally reached Pluto.


New Horizons sped past Pluto early Tuesday morning, making its closest approach at 7:49 a.m. EDT. Pluto was once considered the ninth, and most distant, planet in our solar system, but was downgraded to dwarf planet status in 2005.






A map charting New Horizons' progress





The probe has been snapping hundreds of stunning photos of Pluto and its moons: Charon, which is about the size of Texas, plus the smaller moons Styx, Nix, Kerberos and Hydra. The New Horizons mission has gone smoothly since its launch in 2006 - no small feat, considering that its delicate instruments could be badly damaged by even the smallest space particles as it zips through space at 36,000 miles per hour.




An image of Pluto taken during New Horizon's closest flyby





While NASA engineers celebrated the technical feat, they won't be able to fully exhale until the spacecraft once again makes contact with the tracking station near the Australian capital of Canberra. That's expected to happen on Wednesday morning, at which time New Horizons will upload more high-resolution photos for the world to see. Traveling at the speed of light, transmissions take more than four hours to reach Earth.




New Horizons is about the size of a baby grand piano





New Horizons won't land on Pluto, but it's expected to provide invaluable data to further our knowledge of space. Scientists have already found that Pluto is a little bit bigger - by a diameter of fifty miles - than previously thought. After the probe passes Pluto, it will continue to explore the Kuiper belt - the area of our solar system beyond the planets that contains remnants of the universe's creation. After this, it will eventually leave our solar system entirely and enter interstellar space.