Tuesday, July 14, 2015

Pluto No Longer on the Horizon

This morning, New Horizons became the first spacecraft to make a flyby observation of the Pluto system. During the mission, the spacecraft captured the most detailed photographs of Pluto's surface we've ever had, and possibly ever will have. It also found many new properties including size, mass, atmosphere, and surface composition.

In a period of a few hours, we discovered more about Pluto than we've found in the 85 years since Clyde Tombaugh captured its first photograph.


Before
After
 (images credit: NASA)
To complete this mission, the spacecraft flew for more than 9 years through the emptiness of space. This may sound like a long time, but it's actually amazingly quick. In fact, New Horizons set the record for the fastest speed at launch, and during the flyby, the spacecraft was moving at a rate of over 30,000 mph, or roughly 50 times the speed of sound.

Picture an object twice as heavy as a grand piano moving 25 times faster than a bullet from a gun. Yikes.

The many photos that the spacecraft took during the flyby will be slowly broadcasted, one by one, back to Earth. The first photo, which is supposed to contain Charon, will be broadcasted Wednesday morning. The next one, a composite of Pluto's surface, will take about 8 more hours to retrieve. This is because the transmitter can only broadcast at a rate of 125 bytes per second. At this slow rate, a kilobyte of information would take 8 seconds, and a megabyte would take 8000 (or a little over 2 hours). The rest of the photos and data will be broadcasted over a period of more than a year.

In other words, we'll still be learning more about Pluto and its moons even when New Horizons has long since left the dwarf planet.

If New Horizons still exists, that is. See, NASA doesn't know whether the spacecraft survived the encounter. Pluto could be surrounded by clouds of rocky debris, and collision with a bit of rock as small as a rice grain would prove disastrous for the probe.

For all we know, New Horizons could be flying through space in millions of tiny pieces. It's unlikely, but definitely possible.

A signal from New Horizons is scheduled to arrive in a couple of hours; if we get the signal, only then will we know for sure whether the spacecraft is okay.

In the mean time, we'll just have to wait.


UPDATE
New Horizons has contacted Earth, and it is in good working order. Success! We still don't have the science data, as New Horizons only sent engineering data.


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2 comments:

  1. Pluto? What is the difference between Pluto and Mars?

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    Replies
    1. Pluto has a similar color; however, it is billions of miles farther from the sun (sunlight takes 5 hours to get to Pluto), and it is MUCH colder. On Pluto, it's so cold that carbon dioxide freezes solid. Pluto is also very small - smaller than Earth's moon - and its surface is made of water ice (Mars is made of rock).

      Also, Mars is a planet. Pluto is not.

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