Very nice choice for the holiday!  Happy 4th everyone in the US!

You can also (if you’re lucky) see Hubble zip overhead, here is a tracking site from NASA.

Here’s the press release:
A delicate ribbon of gas floats eerily in our galaxy. A contrail from an alien spaceship? A jet from a black-hole? Actually this image, taken by NASA’s Hubble Space Telescope, is a very thin section of a supernova remnant caused by a stellar explosion that occurred more than 1,000 years ago.

This image is a composite of hydrogen-light observations taken with Hubble’s Advanced Camera for Surveys in February 2006 and Wide Field Planetary Camera 2 observations in blue, yellow-green, and near-infrared light taken in April 2008. The supernova remnant, visible only in the hydrogen-light filter was assigned a red hue in the Heritage color image.

Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

Acknowledgment: W. Blair (Johns Hopkins University)

a tomsastroblog.com post

. . . with the Moon and the star Regulus and we get to see it!

Everyone is going to have an opportunity to check out a nice astronomical event this weekend and you will not need anything special to view it. Better yet, many people are going to be out enjoying fireworks show anyway and this is happening at the same time.   It’s a planetary alignment and if you do happen to be waiting for fireworks you will be right there so have a look.

All you have to do is this:  just after dark on July 4^th, look to the west, close to the horizon, and you will see a very nice grouping: Mars and Saturn right next to the bright star Regulus.  NASA’s sky map can help you get your bearings.  Click here to get PDF version you can print and have with you in case you aren’t too familiar with the night sky.

Same thing on July 5^th except the moon will be much closer to the group. Here’s the sky map for that one. Click here for the PDF version.  Note the sky maps are almost identical so you really only need to print one.

Even after these two nights the planets, Moon and Regulus make for good viewing.  You can find out more about the alignments from Science@NASA.

Skymap credit: NASA

From Sol 31, almost missed this one; it’s a close up of the Wet Chem Lab.  Click here to see picture of the WCL cells for comparison. (Credit: Phoenix web site)

The press release from the Phoenix site:
This portion of a picture acquired by NASA’s Phoenix Mars Lander’s Robotic Arm Camera documents the delivery of soil to one of four Wet Chemistry Laboratory (WCL) cells on the 30th Martian day, or sol, of the mission. Approximately one cubic centimeter of this soil was then introduced into the cell and mixed with water for chemical analysis. WCL is part of the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument suite on board the Phoenix lander.

The Messenger spacecraft took this image as it was departing Mercury.  The time of day would be right about sunrise on this portion of the planet.  Towards the left of the image we can see where darkness takes over, this is the terminator.

It will be a hot day too.  Mercury is roughly three times closer to the Sun as Earth, so the energy the planet gets is about nine times the solar energy what we do. High temperatures will reach, 450 to 600^o F.  Want to hear something really strange?  Because Mercury has a tiny atmosphere, only 10^-12 of Earths, thanks to radiational cooling at night, the temperature will drop to somewhere around – 280^o F.  Sorry to northern folk for using the “rc” term in summer - LOL.

Check the image out on the Messenger website.

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

One hundred years ago this morning, June 30, 1908 an explosion occurred in Siberia, Russia.  Exactly what happened is still a mystery, however the most likely cause of the explosion was an air burst of a meteoroid or comet above the Tunguska River.

The force of the blast is estimated to be about 1,000 times than that of the Hiroshima atomic blast.  Trees were leveled for over 24 miles around (40km), fortunately the impact site was very remote.

Click here to read more, including eyewitness accounts.

Naturally there are some alternative theories, have a look at one of them.

The image above is from the November 14, 2007 entry of the  Astronomy Picture of the Day and it has more information and links too.

A tomsastroblog.com post

On June 30, 2008 the primary Cassini mission will come to an end.

The image above, an engineering test, taken on October 21, 2002 was the first color composite of Saturn and Titan. made with images from Cassini.  The spacecraft was still 177 million miles away (285 million km) from Saturn at the time would take another 20 months to arrive.  See the image in its original context.

So now what?  Fortunately Cassini is in excellent health and a second mission is about to begin.

The Cassini Equinox Mission starts on July 1, 2008 and is scheduled to last until September 2010.

Click here to read a nice overview of the mission and accomplishments, worth checking out too.

From the Cassini press release:
Cassini already revealed parts of the Earth-like and active world of Titan and discovered the potential habitability of Enceladus. The two moons are now the main attractions for exploration in the Equinox mission.

Saturn’s equinox, when the sun shines directly on the equator, occurs in August 2009. This will be an opportune time for Cassini to study the rings in new lighting conditions. Over the past four years, the rings were illuminated from the south, revealing complex dynamics and interactions with moons and moonlets. Cassini will monitor seasonal changes as the angle of sunlight shifts to top of the ring plane and the northern hemispheres of Saturn and its moons.

Titan’s imaging radar and altimeter will make more passes of the haze-covered moon to reveal new terrain. In addition, the spacecraft’s flight path will take it to new places within Saturn’s huge and dynamic magnetic environment.

Image credit:  NASA/JPL/Southwest Research Institute