NASA's Alice instrument on board ESA's Rosetta spacecraft has made a starling discovery.  Rosetta is currently orbiting within 100 miles (160 km) of comet 67P/Churyumov-Gerasimenko.  As the comet moves closer to the sun, more activity on the comet is taking place with jets of water and carbon dioxide spewing off.

The Alice instrument can observe in the far-ultraviolet wavelengths.  This allows scientists to study the chemical composition of gases.  It was discovered that electrons close to the surface of the comet are responsible for the breakup of water and carbon dioxide, not photons from the sun as we previously believed.

Scientists would never have been able to make this discovery without going to the comet.  Because of the Earth's atmosphere, ground based instruments could make these measurements.

As 67P moves closer to the sun, the comet will become even more active, blowing off plumes of water and carbon dioxide.  It is believed that comets can hold the key to how the early solar system formed and what role comets played in providing water to Earth, the building blocks of life.

Over the past 20 years, Hubble has been observing the elliptical galaxy NGC 3862.  It is one of the few active galaxies with jets from a black hole that can be seen in visible light.  Most of the jets are only detected in non-visible wavelengths such as X-ray and Gamma ray.  By comparing Hubble photos taken over the years, a collision between two hight speed knots of ejected material was observed.

When an object encounters a black hole, some matter is ejected back into space.  As the object falls into the black hole, the material is superheated and ejected along the object's spin axis.  One theory says that powerful magnetic fields form the material into a narrow jet.  But if the material is not smooth, the ejected material will form blobs or knots and be shot out into space like a series of cannon balls fired one after another.

Hubble's photos revealed knots shot off after others have a faster speed and eventually catch up to the previous knot and rear-end it causing a shock collision.  Why does the second knot move at a faster speed?  One explanation is that perhaps the first knot cleared out the space and the second knot had less drag since it was traveling through "cleaner" space.

As New Horizons gets closer to Pluto, the Hubble Space Telescope has been looking at the planet and its moons in advance of the spacecraft's arrival.  New data shows that two of Pluto's moons, Nix and Hydra, wobble unpredictably.  If you were on one of the moons, you would never know when or from what direction the sun would rise or set, nor when you would see Pluto or not.  The moons just wobble about in any old direction that cannot be plotter nor predicted.  They are shaped like a football or rugby ball.

The most likely cause is the gravitational field shifts constantly.  This is because Pluto is really a double planet system.  Charon and Pluto orbit each other from one central point between them.  If you were on one side of Pluto you would always see Charon, if you were on on the other side of Pluto you would never see Charon.  Charon is about half the size of Pluto.

It is likely that Pluto's other moons, Kerberos and Styx act the same way as Nix and Hydra. An interesting fact about Kerberos is that it is dark, described as the color of charcoal.  The other moons are bright and sandy colored.  The reason for this is unknown.

New Horizons will fly by the Pluto system next month.  Hubble has given us tantalizing taste of what we will find there.