We Reach Pluto Tomorrow! 10 Fast Facts About 'New Horizons'

NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Tomorrow morning, July 14, at 7:49 am ET, the spacecraft New Horizons makes its closest approach to Pluto in history. We'll be nearer to Pluto than New York City is to Hong Kong. Over the coming months the spacecraft will return libraries of knowledge about the mysterious planet. Here are a few things you might not know about the extraordinary probe.

1. New Horizons is the fastest spacecraft ever launched.

In 2006, an Atlas V rocket blasted New Horizons into space. By its third separation stage, the spacecraft was traveling a shade under 10 miles per second. To give some idea of its speed, it took the Apollo astronauts three days to get to the moon. New Horizons reached the same distance in nine hours.

2. Jupiter’s gravity acted as a slingshot on the probe.

A “gravity assist” involves a spacecraft flying near a planet and using that planet’s gravity to change speed or direction, as if flung by a giant slingshot. Jupiter’s gravity hurled New Horizons an extra 9,000 miles per hour, ramping up its speed to 52,000 miles per hour. While traveling through the Jovian system, New Horizons gave its instruments a test run, capturing such never-before-seen phenomena as lightning near Jupiter’s poles.

3. It is carrying the ashes of the man who discovered Pluto.

In 1930, Clyde Tombaugh, an American astronomer at the Lowell Observatory, discovered the planet that was eventually named Pluto. Tombaugh died in 1997, and New Horizons is carrying a small amount of his ashes. When the probe eventually moves beyond the Kuiper Belt, Tombaugh's ashes will be the first to travel beyond our solar system. The probe also carries a CD-ROM containing the names of 434,000 people who signed up to have their names sent to Pluto.

4. Planetary scientists consider Pluto a “science wonderland.”

That’s how the team at Johns Hopkins University’s Applied Physics Laboratory, which operates the New Horizons mission for NASA, describes the Pluto system. In addition to mapping Pluto’s geology and morphology, and analyzing its atmosphere and weather, New Horizons will study Charon, Pluto’s largest moon. By orbiting around a common center of gravity, the two worlds make up the only “binary planet” in the solar system. This is the first time we can study a new planetary class known as “ice dwarf” (the other two in our solar system being terrestrial planets and gas giants).

5. The entire mission will use less power than two 100-watt bulbs.

The energy efficient spacecraft is powered by a radioisotope thermoelectric generator (RTG), a kind of plutonium power plant. Like a big thermos bottle, the spacecraft is wrapped in thermal blankets (the gold foil seen in photographs) to hold in the heat produced by the spacecraft’s electronics, keeping them at a stable temperature. Notably, the RTG doesn’t provide propulsion. The spacecraft is still flying on the speed created by the launch and Jupiter’s gravity assist.

6. Its data is transmitted to Earth at 2 kbps.

The spacecraft uses a giant dish antenna to communicate with NASA’s Deep Space Network. It’s no trivial effort, though; the beam is only 0.3-degrees wide and has to hit Earth from Pluto and, eventually, beyond. (Considering the distances involved, New Horizons is quite the sharpshooter.) It takes four hours for data to arrive at the spacecraft, and once the flyby is complete, the probe will need a full 16 months to send all the data home.

7. There is almost zero margin for error.

The numbers are astonishing: New Horizons has traveled 3 billion miles at approximately 31,000 miles per hour (currently) and, if all goes as planned, will hit a target just 200 miles across. Because of orbital mechanics, if it is 100 seconds off course, it will not be able to gather 100 percent of the desired scientific data. Think about that: 100 seconds off course from a travel time of 9.5 years. Now that’s precision.

8. New moons mean new dangers.

In 2011, New Horizons discovered a second moon orbiting Pluto (Kerberos), and a year later a third (Styx). That’s been both exciting and worrying. These moons lack the mass and gravity to keep debris caused by planetary collisions from flying into space, where they could potentially smash into New Horizons. Debris doesn’t have to be big to be a threat: a piece the size of a grain of rice could prove catastrophic to the probe. Think of a rock hitting your windshield. Now imagine if you were driving 31,000 miles per hour.

9. The USA is the first country to explore every planet in the solar system.

NASA has been the first to launch each spacecraft that has successfully visited every planet, starting with Mariner 2 in 1962. July 14 is also the 50th anniversary of the Mariner 4 mission to Mars, the first exploration of the red planet. New Horizons completes humanity’s reconnaissance of the classical solar system.

10. The New Horizons mission does not stop with Pluto.

Once the spacecraft passes Pluto, it will have enough power and propellant to continue into the Kuiper Belt, a gigantic zone of icy bodies and mysterious small objects orbiting beyond Neptune. These objects are the building blocks of Pluto and planets like it. The new course will take New Horizons one billion miles beyond Pluto.

First-Ever Map of Titan Reveals That Saturn’s Moon Is a Lot Like Earth

NASA/JPL-Caltech/Univ. Arizona/Univ. Idaho
NASA/JPL-Caltech/Univ. Arizona/Univ. Idaho

If there's any life in this solar system outside Earth, we likely won't find it on Mars or even on another planet. Saturn's moon Titan is the place in our celestial neighborhood that's most similar to our own home, and it's where scientists think we have one of the best chances of discovering life. Now, as Nature reports, newly visualized data shows just how much Titan has in common with Earth.

Between 2004 and 2017, the NASA spacecraft Cassini performed more than 100 fly-bys of Saturn's moon. Titan is unique in that it's the only moon in the solar system with clouds and a dense, weather-forming atmosphere. This has made it hard to study from space, but by flying close to the surface, Cassini was able to capture the landscape in an unprecedented level of detail.

Map of Titan.
The first global geologic map of Titan.

NASA's new map of Titan, published in the journal Nature Astronomy, reveals a varied world of mountains, valleys, plains, and sandy dunes that starkly contrast with the desolate wastelands we've seen on neighboring planets. It's also home to seas and lakes, making it the only place in the solar system other than Earth with known bodies of liquid. But instead of water, the pools mottling the moon's surface consist of liquid methane.

Even with its Earth-like geology and atmosphere, chances of finding life on Titan are still slim: Temperatures on the surface average around -300°F. If life does exist there, it's likely limited to microbes in the moon's craters and icy volcanoes.

It will be a while before NASA is able to study Titan up close again: NASA's next drone mission to the body is set for 2034. Until then, scientists have plenty of data recorded by Cassini to teach them more about how the moon formed and continues to change.

[h/t Nature]

A Rare Unicorn Meteor Outburst Could Be Visible for Less Than an Hour on Thursday

joegolby/iStock via Getty Images
joegolby/iStock via Getty Images

Your chances of seeing a unicorn this week are slim, but if you look up on Thursday night, you may see something that's almost as extraordinary. As Sky & Telescope reports, the upcoming Alpha Monocerotid meteor shower could produce a meteor outburst, which means there could be multiple shooting stars per second streaming from the unicorn constellation.

What is a unicorn meteor shower?

There's nothing particularly magical about the Alpha Monocerotids. They appear to originate near the star Procyon, which is next to the constellation Monoceros, the Greek name for unicorn.

The shower is known for occasionally packing a dense flurry of activity into a brief viewing window. The meteors appear between November 15 through the 25th of each year, and peak around the 22nd. Several times a century, the shower treats sky gazers to an "outburst" of shooting stars that lasts less than an hour.

Such an outburst is predicted for 2019. According to astronomers Peter Jenniskens and Esko Lyytinen, the Earth is on track to pass through a thick portion of the tail of the unknown comet that provides debris for the shower. The conditions are almost the same as they were in 1995, when the Alpha Monocerotids lit up the sky at a rate of 400 meteors per hour, which is approaching meteor storm levels. For that reason, the scientists are expecting shooting stars to appear in the same numbers this time around.

How to see the meteor outburst

Timing is crucial if you want to catch the Alpha Monocerotids, even more than with regular meteor showers. The outburst is expected to start at 11:15 p.m. EST and last just 15 to 40 minutes. Luckily, the sun will be fully set by then and the crescent moon won't rise until after 2 a.m, creating optimal viewing conditions for the eastern half of the country. The shooting stars are fast—traveling at 40 miles per second—and they come at random. Don't be surprised to wait a minute between meteors during some parts of the outburst and less than a second at others.

[h/t Sky & Telescope]