Coming Up: Pi Day, Einstein’s Birthday, and Dawn at Ceres

Saturday, March 14, 2015 is “pi day” – the only day this century that includes the first five digits of pi or 3.1415…   This year, several groups are suggesting that this might be a good day for celebrating math and science in general – and raising our voices in favor of evidence-based, well-reasoned decisions in our public life.  It’s a time we can share with others our conviction that evolution is well-established fact, that climate change is being accelerated by human activities, and that NASA did indeed land people on the Moon – all ideas being denied on the web, in the media, and in our political discourse.

March 14^th is also Albert Einstein’s birthday (he was born in 1879 on that day.)  This year, we celebrate the 100^th anniversary of Einstein’s first paper on the General Theory of Relativity, the brilliant insight that connects gravity, light, space and time.  This anniversary is part of a larger physics commemoration – celebrating 2015 as the International Year of Light.  At Foothill College, I will be offering my evening Physics 12 class (Physics for Poets), all about Einstein’s life and work, explained without math.  It ends with recent contributions to our understanding of the universe by Stephen Hawking (whom I was pleased to see getting the Academy Award for best actor :-)) 

We can also celebrate the big development in the solar system: The Dawn Spacecraft just went into orbit around the largest asteroid in the asteroid belt, Ceres, which, by virtue of its size and round-ness, also qualifies as the first dwarf planet to have been discovered (in 1801).  Dawn is the first spacecraft ever to orbit two worlds on the same mission, thanks to its advanced ion-propulsion technology.  (It orbited the second largest asteroid Vesta, from 2011 to 2012 and then made its way across 900 million miles of space to Ceres.)  We are expecting remarkable close-up images of and data from Ceres as the year goes on and Dawn achieves closer and closer orbit. Stay tuned.

For the latest on the Dawn mission, see the blog by Mission Director Marc Rayman: http://dawnblog.jpl.nasa.gov/ 

For a syllabus of my Physics 12 (Einstein) class, see: www.foothill.edu/physics/Physics.12.Web.pdf

For a guide to resources for answering conspiracy-theory "true believers", go to: http://www.astrosociety.org/education/astronomy-resource-guides/astronomical-pseudo-science-a-skeptics-resource-list/ 

Painting of the Dawn Spacecraft Near Ceres (NASA)

Water Found on Largest Asteroid

Astronomers working with the Herschel space observatory have discovered water vapor coming from the largest asteroid in the asteroid belt, the one called Ceres (pronounced like "series"). By strict definition, Ceres is so big and round that it is no longer considered an asteroid, but is now designated dwarf planet number one (having been discovered on Jan. 1, 1801, long before Pluto).

Ceres is about 600 miles across and takes 4.6 years to orbit the Sun (Mars takes 1.9 years, while Jupiter takes 12 years.) The Hubble Space Telescope images of it (see one attached here) show lighter and darker areas. The water vapor is not evenly distributed around Ceres and there is more of it when Ceres is closer to the Sun, so there may be some ice that is sublimating (going from frozen form to vapor) in parts of Ceres.

At Ceres' distance from the Sun, ice on the surface would have all sublimated long ago, so this must be vapor coming from a deeper (frozen) layer, which was a surprise. Some astronomers think there may be enough water ice under the surface of Ceres to make an ocean. This is the first time water vapor has been detected in the asteroid belt, although we have seen it coming from a moon of Jupiter's and a moon of Saturn's. There may be plumes or "geysers" of water vapor coming from parts of Ceres, perhaps like the ones on Saturn's satellite Enceladus.

We will know a lot more about conditions on Ceres next March and April, when the Dawn spacecraft arrives for a rendezvous with Ceres and provides images with unprecedented detail of this intriguing member of our solar system. (Dawn gave us lots of great information about Vesta, the second largest asteroid, before it departed for Ceres in 2012.) Isn't it great how nature continues to surprise and delight us as we explore our cosmic neighborhood?