This delicate bubble is the remnant of a supernova, SNR 0509-67.5, which is located in the Large Magellanic Cloud, about 160,000 light-years from Earth.

Source: Hubblesite.org

The nebula is about 23 light-years across and is expanding at more than 11 million miles per hour.  The image was provided by Hubble and augmented below with data from the Chandra X-ray observatory.  The blue and green gossamer structure in the center is material heated by the expanding shock-wave of the supernova, which occurred almost 400 years ago.

Source: Hubblesite.org

See the Hubble site for more information and images.

Till next time,

RC Davison

NASA’s press conference today (December 2, 2010) revealed that there is a bacteria that can use arsenic instead of phosphorous to survive.  Phosphorus is one of the  six basic elements required for “life as we know it”—the others being, carbon, hydrogen, oxygen, nitrogen, and sulfur. This expands the opportunities for finding life elsewhere in the Universe.

When you couple the information about these unique bacteria with the news release from Yale’s Professor Pieter van Dokkum that there are probably three times as many stars (300 sextillion!!) in the universe than previously thought, you have a whole lot of opportunities for life in the cosmos!  This announcement is about red dwarf stars, which are smaller and cooler than our Sun and have extremely long life times because they use their hydrogen fuel at such a slow rate.

One last bit of information that came out this week is from the European Southern Observatory.  Astronomers were able to analyze the atmosphere of a “super-Earth” GJ 1214b, as it passed in front of its parent star GJ1214.  The results showed that the planet has an atmosphere mostly made of water in the form of steam or at the very least it is dominated by thick clouds or haze.  This was gleaned from a planet that is over 40 light-years from us and orbits its star every 38 hours at a distance of about 2 million kilometers.  (Note that we are about 150 million km from our Sun.)

To summarize this week’s events: We’ve got a form of life on Earth that lives off an element that is poisonous to most life on our planet; three times as many stars that may have planets in the Universe; extrasolar planets that have water vapor in their atmospheres.  Sounds to me like the odds for extraterrestrial life is getting better and better!

It’s about time that ET phones our home!

Till next time,

RC Davison

For those of you that celebrate, appreciate, or just tolerate Halloween, I offer you a cosmic witch to look out for!

Catching some rays from Orion’s blue supergiant – Rigel, the witch is actually a reflection nebula (hence the bluish color) that is over 50 light-years long.   The Witch Head Nebula (IC 2118) is about 1000 light-years distant, so we have nothing to fear from this witch on Halloween!

Click the link for more information about, and a larger image of the Witch Head Nebula.

Till next time,

RC Davison

When I look at a globular cluster like Omega Centauri I always imagined that the 10 million stars in the cluster rotated majestically about a central mass in an orderly fashion.

Thanks to some new work by two astronomers from the Space Telescope Science Institute in Baltimore, Md, my peaceful, orderly vision of a globular cluster has been trashed!

Jay Anderson and Roeland van der Marel, using data from the Hubble Space Telescope, have measured the velocities of some of the stars at the heart of the cluster and their motion is far from peaceful!

In the close-up image below, we see the brilliant blue and red stars that reside in the center of this ancient globular cluster.  The area in the rectangle is magnified and displayed below showing the relative velocities of the stars contained within.

Source: Hubblesite.org

This motion was gleaned from images Hubble took in 2002 and 2006.  Its precise optics allowed the astronomers the ability to measure the relative motion of these stars over such a short period of time.

In the Hubble clip below, you will zoom into the heart of Omega Centauri and ultimately see the predicted motions for these stars over the next 10,000 years.  It is interesting to note that this random motion gives astronomers clues that may dispel the theory of a massive black hole at the center of globular clusters.  There may be a black hole present, but it would not be equivalent to the massive black holes found in the center of galaxies, like the one at the center of the Milky Way, which is about 4 million times the mass of our Sun.

Till next time,

RC Davison

My post on August 21, 2010, “Do They Know We’re Here?” contains a bit of misinformation, which I hadn’t thought of until reading the latest Planetary Report from the Planetary Society.

While we’ve been experimenting and transmitting radio signal for over a 100 years, those early transmissions were low frequency, typically 1 MHz or less.  The ionized layer of our atmosphere – the ionosphere, reflects those signals back down to the surface, so they won’t escape the planet.

If any of you have listened to AM radio (Remember that?) at night, you find that you can pick up stations from 100s to 1000s of miles away, whereas you can’t hear them during the day.  This is because at night, the sunlight is no longer showering the atmosphere with UV radiation, which knocks electrons off the oxygen and nitrogen atoms charging them – ionizing them.  The lower layer of the ionosphere rapidly dissipates when the Sun sets, leaving the higher layers to reflect the AM transmissions, allowing them to reach much further.

We don’t see this with our FM radios,  because they operate at much higher frequencies (in the 10-100 MHz range) and don’t rely on the ionosphere to  reflect them to your radio.  For your radio to receive your favorite FM station, you have to be able to receive the signal directly from the transmitting antenna, this is why they are called “line-of-sight” transmissions.  These higher frequencies were used commercially for FM radio and early television in the early 1930s, and they blasted right through the ionosphere and out into space.

So, a long winded explanation to say that we’ve really been broadcasting to the cosmos for about 75 years, as opposed to the 100 years mentioned in the earlier post.

Comments always welcome!

Till next time,

RC Davison