Sfair’s blog

I

will go to

to study the ring system of

and I’ll be right back. Maybe not.

(thanks to michele)

I was trying to install o maple 9.5 on Ubuntu Gutsy and I got this error:

Preparing to install...
Extracting the JRE from the installer archive...
Unpacking the JRE...
[...]
nawk: error while loading shared libraries: libm.so.6: cannot open shared object file: No such file or directory
[...]
Launching installer…
grep: error while loading shared libraries: libc.so.6: cannot open shared object file: No such file or directory
/tmp/install.dir.4876/Linux/resource/jre/bin/java: error while loading shared libraries: libpthread.so.0: cannot open shared object file: No such file or directory


The first step was to check if libc.so.6 was correctly installed (you can find it in libc6 package). Once I knew it was installed I looked for a solution and I found on Ubuntu forum a recipe to solve this issue:

1- Copy the file LinuxInstaller.bin to your computer (it’s often located in /media/cdrom/Linux/Disk1/InstData/VM)
2- Open a terminal window and type:

sed -i "s/export LD_ASSUME_KERNEL/#xport LD_ASSUME_KERNEL/" LinuxInstaller.bin

3- Change the file permission and execute it:

chmod +x LinuxInstaller.bin
sudo sh ./LinuxInstaller.bin

4- Proceed with installation as usual (just point to /media/cdrom/Linux/Disk1/ when Disk 1 be request).

Do you like astronomy? Do you have a not-so-small telescope available? Do you want to be a hero?

You can help astronomers to find a giant storm in Saturn’s atmosphere. Cassini spacecraft detected an anomalous strong radio emission coming from the planet and scientists want to locate the source responsible for this emission.

Carolyn Porco, manager of Cassini Image Science Subsystem (Cassisi ISS), has just sent an e-mail to Ciclops Alliance members inviting amateur astronomers to help in this hunt:

Now, here is another fun homework assignment for those amateur (or professional!) astronomers among you with reasonably good telescopes at your disposal.

Yesterday, the instrument on Cassini that can detect radio signals from the planet once again picked up strong emissions. First in 2004 (http://ciclops.org/view.php?id=870) and again in 2006 (http://ciclops.org/view.php?id=1865), we Cassini folks noticed that the radio emissions were correlated with giant thunderclouds seen in the southern hemisphere in what we called `story alley’: a latitudinal band centered around 35 degrees south latitude. This tipped us off that the emissions might in fact be due to lightning arising in giant Saturnian storms.

With new emissions coming from the planet, we want to find the thunderstorm responsible for them. The trouble is: our cameras will not monitor Saturn’s entire atmosphere on a daily basis during the next 10 days. So, we have little chance of actually finding this storm in our images.

That’s where you amateur astronomers come in! We’d like you to help us find the thundercloud that the radio emissions are coming from. And what we need for thundercloud identification are images of Saturn at the best possible spatial resolution and monitoring all longitudes every couple of hours. The most important region to cover is the hemisphere of 300 Western longitude (in the longitude system defined by the International Astronomical Union, IAU). [Tonight 300° will be in the center of Saturn around 04:30 Universal Time. At that time, Saturn is relatively high in the sky (about 47° for an observer at the latitude of Paris). Of course each astronomer has to convert this UT to his/her local time.] Saturn’s rotation period is about 10 hours, 40 minutes.

And we could use images taken in any and all wavelengths - broadband covering all visible sectrum and, if possible RGB, and the methane absorption bands.

Feel free to discuss this on the CICLOPS site, if you like. I suggest using the Dragon storm image (http://ciclops.org/view.php?id=870) as the comment page.

And if you do manage to see anything on Saturn, please email me immediately!

You will become an instant hero, and we’ll issue a press announcement about this project and your participation.

Happy Storm Chasing!
Carolyn

Recently I upgrade a PC from Ubuntu Fesity to Gusty using the update manager. When the upgrade was completed, nautilus presented a strange behavior: it crashed every time I tried to open a folder, returning the following message:

file nautilus-navigation-window.c: line 834 (activate_nth_short_list_item)

I looked for this error in ubuntu forum, but I couldn’t get what’s wrong. I just discovered this crash happens only when you upgrade your system using the update manager.

There are two ways (at least the ways I know) to solve temporally this problem:

(a) Change the view mode on nautilus to view as list
(b) Downgrade some packages (nautilus, libnautilus e nautilus-data):

cd /var/cache/apt/archives
sudo apt-get install libtrackerclient-dev
sudo dpkg --force-all -i nautilus_1%3a2.20.0-0ubuntu7_i386.deb libnautilus-extension1_1%3a2.20.0-0ubuntu7_i386.deb nautilus-data_1%3a2.20.0-0ubuntu7_all.deb

This bug was reported and a patch was released to fix it (SVN version is ok). Probably it will be available in the next nautilus update.

After a long time my Master’s Thesis is online. In this work, entitled “Analysis of the Saturn’s F-ring Region”, we analyse the influence of Prometheus and Atlas on F-ring particles and also on two diffuse rings.

The text is available in PDF format (4.3MB) (I’ll convert to djvu soon). You can download it here (90 pages, pt_br).
Comments, suggestions and job proposals are welcome

The abstract:

The Cassini-Huygens arrival into the Saturnian system brought a large amount of data about the satellites and rings. Two diffuse rings were found in the region between the A ring and Prometheus. R/2004 S1 is coorbital to Atlas and R/2004 S2 is close to Prometheus.
In this work we analyse the closest approach between Prometheus and both rings. As a result we have found that at each period of the satellite a gap is created in the inner F-ring’s strand and waves are formed in the further strands. Prometheus also scatters particles from F-ring and a similar behaviour occurs in the R/2004 S2 ring, with gap formation and particle scattering. The numerical simulations has shown that Prometheus does not influence the R/2004 S1 ring but Atlas is responsible for the formation of three regimes in this ring, as expected for a satellite embedded in a ring.
The determination of Lindblad and corotation resonances showed that there is an overlap of resonances in the region of the R/2004 S2 ring. Furthermore, the computation of the Lyapunov Characteristic Exponent has revealed that the R/2004 S2 ring lies in a chaotic region.
When solar radiation pressure effects are considered, micrometre-sized particles from F-ring decay and collide with Prometheus, except for few particles of 1µm which cross Prometheu’s orbit and reach the R/2004 S2 region. The solar radiation pressure affects the behavior of the R/2004 S1 ring leading to collisions between Atlas and these small particles, although some of them decay in direction of Saturn.

Keywords: F-ring, planetary rings dynamics, resonances, Lyapunov Characteristic Exponent, solar radiation pressure

Definition
Let JD be the Julian Day corresponding the first day of a generic meeting M.

Theorem
If you submit a paper A for M, then your poster PO or your presentation PR won’t be finished before JD-5.

Are you an astronomy enthusiast? Do you want to contribute to scientific research? It’s easier than you think and you don’t need to be an expert on astronomy to help.

GalaxyZoo is an online project which intends to classify galaxies according their shape, that could be elliptic, spiral (subdivided into clockwise or anticlockwise rotation), irregular or merged galaxies. It seems to be an easy task, but as the project developers say:

“… the human brain is much better at recognizing patterns than a computer can ever be. Any computer program we write to sort our galaxies into categories would do a reasonable job, but it would also inevitably throw out the unusual, the weird and the wonderful. To rescue these interesting systems which have a story to tell, we need you.”

So, how to proceed:

1. Before start working, I strongly recommend you to read carefully the tutorial available here
2. Once you understand the procedure and feel confident to classify go to the project website and create an account
3. After register, you need to do a small trial where you must correctly classify 8 or more galaxies (of 15)
4. After finish the trial, you’re read to have fun

Thanks to Luiz Armesto that remember me about this project.