NASA

In 2006, Pluto was demoted from planet to “dwarf planet”—a reclassification that satisfied astronomers who felt it’s mass was too small to be a true planet. However, many people who grew up including Pluto in their solar system mobiles and ceiling decals were too emotionally attached to let it go.

Now, Pluto is back in public scrutiny, but not because it’s being reinstated (sorry, Pluto lovers). The New Horizons spacecraft, which has flown over 3 billion miles in nine and a half years, is close enough to take photographs of Pluto and provide the first accurate measurements of it in history.

This once-in-a-lifetime event is an exciting step forward in astronomy and will help us learn more about our solar system. Here are 11 facts about Pluto and NASA’s exciting New Horizons mission, featuring some unique visualizations from FindTheData:

11. Pluto was still a planet when New Horizons was first launched.

In 2005, Eris was discovered, which shared many of the same characteristics with Pluto. Astronomers were then faced with the decision to dub Eris the 10th planet or change the way we define planets altogether. When New Horizons first took off, this big debate was gaining steam.

10. New Horizons is the fastest spacecraft ever launched by NASA.

When New Horizons was strapped on an Atlas V rocket and blasted off into space at over 36,000 miles per hour, it set the record as the fastest launch in history. According to Business Insider, the spacecraft reached the Moon nine hours later—eight times faster than it took the Apollo astronauts.

9. Pluto is really, really far away.

As New Horizons project manager Glen Fountain put it, “this 9 1/2-year journey to a tiny keyhole in space some 3 billion miles from Earth is the equivalent of a golfer on the East Coast hitting a ball across the continent and making a hole-in-one in Los Angeles.”

For reference, here are the distances to all planets in our solar system:

 

Planets by Distance from the Sun | FindTheData

8. It’s taken almost decade to get there.

It took New Horizons about a year to reach Jupiter, which is 365 million miles away. It took about 9.5 years to reach Pluto, which is 4.67 billion miles from Earth.

Here’s the timeline of the New Horizon’s Mission to Mars:

Timeline: New Horizon’s Mission to Pluto | FindTheData

7. And we haven’t really been able to figure out exactly how big it is, until now.

Estimated Size of Pluto | FindTheData

6. High school interns were among those who helped launch the spacecraft.

Those high schoolers are still working on the mission almost a decade later…and getting their Ph.D.s.

5. New Horizons spent some time hibernating.

After it left our solar system, the spacecraft hibernated over 1,873 days — about two-thirds of its flight time. This was to prevent wear and tear of the vessel and reduce the risk of system failures. NASA fired it back up once it was in close range to Pluto, and it has since been taking some of the first close-range photos.

4. Here is the best photo taken of Pluto by the Hubble Telescope:

Best Photos Taken of Pluto by the Hubble Telescope | FindTheData

3. Here is what we’ve seen recently:

New Horizon’s Photos of the Approach to Pluto | FindTheData

2. Pluto, as it turns out, has a heart.

New Horizon’s Photo of Pluto’s Heart | FindTheData

On July 7, the camera aboard New Horizons, called the Long Range Reconnaissance Imager (LORRI), captured one of the first detailed images of Pluto (it was just under 5 million miles away). What astronomers saw on that particular side was areas of “varying brightness,” according to Tricia Talbert of NASA.

There’s an “elongated dark feature at the equator, informally known as ‘the whale,’ and a large heart-shaped bright area measuring some 1,200 miles across on the right.” Above these is a dimly-lit polar region.

1. And, finally, here are the best pictures captured by New Horizons today:

The Best Photos Ever Taken of Pluto | FindTheData