(The following is an open letter to Greater New Milford-area residents from the volunteers at the McCarthy Observatory on the campus of New Milford High School.)

Dear friends of the McCarthy Observatory,

In our January letter, we mentioned some very important and exciting voyages of discovery in the solar system this year.

Things are progressing superbly, so an update is in order. Nothing in recent memory has come close to the solar system pioneering events of 2015, from Mercury all the way to Pluto -- and beyond.

Starting at the part of the solar system closest to the sun:

The Messenger mission to explore Mercury ended April 30 most successfully by deliberately crashing into the surface of the planet, ending 49 months of a science-rich study of a planet that little was known about.

Messenger had completed its primary mission by March of 2012, but performed so well it was extended for more than three years. It has delivered a treasure trove of information that will take many years to fully examine.

Key findings include determining Mercury's surface composition, revealing its geological history and finding water ice in craters at its poles.

The Rosetta mission has continued moving along next to Comet 67/P, examining the four-kilometer ice and rock structure as it nears the sun and gets affected by ever-stronger solar radiation.

Hope remains it will regain transmission from the Philae probe on the comet, but superb science information will be gained even if this fails. 67/P continues to enrich our knowledge of comets in many ways.

The Dawn mission vehicle is doing great in its close encounter with dwarf planet Ceres.

Dawn arrived in orbit March 6 and is orbiting at about 8,400 miles above Ceres. This is the first of four mapping orbits, eventually getting to a 230-mile orbit. Dawn will soon move inward to an orbit of 2,700 miles.

High intrigue surrounds the discovery of two very bright white areas at the base of one of the many craters on Ceres.

Mysteries energize science. We love them. New mysteries appear everywhere in space very often.

Last, but maybe best of all, the New Horizons vehicle is fast approaching the Pluto system, with better images starting to show surface features, now in color, getting into focus... .a first for mankind.

There is a real possibility a polar ice cap is visible. On July 14, right on schedule, the vehicle will zip by, and will continue to study Pluto for a long period as it then alters course to intercept another dwarf planet much farther out in what is known as the Kuiper Belt of many dwarf planets far beyond Neptune.

The next object after Pluto was discovered by, of course, the Hubble telescope, responding to a fervent plea by the New Horizons team to find such an object in time for the vehicle to plot a course.

The Hubble also discovered four additional moons of Pluto since New Horizons was launched in 2006. The latest animated image of the Pluto/Charon system is at www.planetary.org/blogs/emily-lakdawalla/2015/04291753-new-horizons-sees-surface.html.

The Opportunity rover's steady progress in exploring Mars has now exceeded the distance run in marathons on earth, the Curiosity rover just discovered evidence of the existence of water vapor in the Martian atmosphere, Hubble has demonstrated there is a vast liquid water layer on Jupiter's moon Ganymede, and the Cassini mission around Saturn is determining much about the water reservoirs on moons Enceladus and Titan.

We are finding the solar system is a very soggy place.

This is shaping up to be possibly the greatest year ever for solar system science.

Stay tuned.

The volunteers

McCarthy Observatory

New Milford