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Caitlin: Remember when Pluto was the 9th planet?  Good times.  But a few months before Pluto was reclassified as a dwarf planet and ruined everyone's grade school mnemonics, NASA sent off a probe to study it.  In January 2006, New Horizons was launched on a nearly 5 billion kilometer journey.  And just this week, the little probe began the first stage of its historic mission, by waking up from a very long nap.  To conserve power, the probe has spent the last nine years in hibernation mode, but now that it's only 220 million km away, New Horizons has been activated and is preparing to make long range observations, beginning this Sunday, January 25th. 

At first, Pluto will just be a blip on the craft's camera screen, but over the next few months, that little dot is going to grow until May, when New Horizons starts to get a better picture than even Hubble can.  Then the fun really starts.  Around July 14th, New Horizons will reach its closest approach, and conduct the first ever fly-by of the dwarf planet, and give us the first good look at Pluto's surface.  The probe will also check for signs of liquid water, which we've found on other far off frozen worlds, like Europa and Titan.  Pluto's surface is frozen solid, but some astronomers think the heat from radioactive decay inside the dwarf planet might have melted some of the ice underneath.  So if we see geysers or volcanoes or detect warm spots, we'll know there's liquid water down there. 

So New Horizons may be small, the craft itself is only about the size of a piano, but the implications for its mission are huge.  And even though we talk about it a lot, this is actually the first mission to explore the billions of small frozen bodies beyond Neptune, in the area known as the Kuiper Belt.  The objects in the Kuiper Belt are relics of the whirling cloud of interstellar gas and dust that eventually turned into our solar system.  They're similar to the smaller bodies that were the planets' main ingredients, but they didn't get smashed around enough to actually combine into planets themselves.  So studying them could give us a much better picture of how the solar system formed, and Pluto's the biggest Kuiper Belt object that we know of, so it's a fascinating place to start.  We'll be sure to keep you posted on New Horizons' progress, but I'm warning you, we're all going to have to be patient.  NASA says it'll take a year to download all the data from the probe.  What are they, on dial-up? 

Meanwhile, though, we'll be getting another fly-by a bit closer to home, on Monday, January 26th, Asteroid 2004 BL86 is going to pass right by us, buzzing earth from about 1.2 million km away.  That's three times the distance to the moon, so we're definitely not in any danger, but at more than half a km long, the asteroid is nothing to sneeze at.  But you shouldn't sneeze at anybody, that's rude.  Using NASA's deep space network antenna at Goldstone, CA, and Puerto Rico's famous Arecibo Observatory, astronomers plan to shoot microwaves at the asteroid and record how they bounce back, giving us a pretty good picture of what the object looks like.  And you can probably get a glimpse yourself.  If you have access to a small telescope or a powerful set of binoculars, and you live in Africa, the Americas, or Europe, you should be able to see it moving north, through the constellation Cancer.  This will be our closest visit by an object this large until 2027, when asteroid 1999 AN10 will pass closer to Earth than the moon  Closer than the moon! 

Thanks for joining me for SciShow Space News.  If you want to support SciShow and get yourself some swag like a SciShow tie or a personalized lab coat, check out Subbable.com/SciShow, and don't forget to go to youtube.com/scishowspace and subscribe. 

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