Gliese 581c is a “super-earth” extrasolar planet orbiting the red dwarf star Gliese 581. It appears to be the first terrestrial extrasolar planet discovered in the hypothetical habitable zone surrounding its star, where surface temperatures might maintain liquid water and therefore be suitable for life as known on Earth. The planet is astronomically close, at 20.4 light years (193 trillion km or 119 trillion miles) from Earth in the direction of the constellation of Libra. Its star is identified as Gliese 581 by its number in the Gliese Catalogue of Nearby Stars; it is the 87th closest star system to the Sun that we know of.

Gliese 581c is the first extrasolar planet believed to possibly have a surface temperature similar to that of Earth. Assuming the planet’s mass is close to the lower limit determined by radial velocity measurements (the true mass is unknown), it would be the smallest known extrasolar planet around a main sequence star to date.

Discovery
The discovery of the planet by the team of Stéphane Udry University of Geneva’s Observatory in Switzerland was announced on April 24, 2007. The team used the HARPS instrument (an echelle spectrograph) on the European Southern Observatory 3.6 m Telescope in La Silla, Chile. The team employed the radial velocity technique to identify the planet. The Canadian-built MOST space telescope was used to conduct a follow-up study over the next six weeks. No transit was detected over this time, so a direct measurement of the planet has not yet been possible; however, the star’s apparent magnitude changed very little, indicating that it provides a stable source of light and heat to Gliese 581c.

The team released a paper dated April 27, 2007, published in the July, 2007 journal Astronomy and Astrophysics. In the paper they also announced the discovery of another planet in the system, Gliese 581d, with a minimum mass of 7.7 Earth masses and a semi-major axis of 0.25 astronomical units.

Mass
The existence of Gliese 581c and its mass have been measured by the Radial Velocity Method or the “wobble” method of detecting exoplanets. The mass of a planet is calculated by the small periodic movements around a common centre of mass between the host star Gliese 581 and its planets. Because the “wobbling” of Gliese 581 is a result of all planets in its system, the calculation of the mass of Gliese 581c depends on the presence of other planets in the Gliese 581 system and on the inclination of the orbital plane with respect to Earth. Using the known minimum mass of the previously detected Gliese 581b, and assuming the existence of Gliese 581d, Gliese 581c has a mass at least 5.03 times that of Earth. The mass of the planet cannot be very much larger than this or the system would be dynamically unstable.

Radius
If it is a rocky planet with a large iron core, Gliese 581c has a radius approximately 50% larger than that of Earth, according to Udry’s team. Gravity on such a planet’s surface would be approximately 2.24 times as strong as on Earth. If Gliese 581c is an icy and/or watery planet, its radius would be less than 2 times that of Earth, even with a very large outer hydrosphere, according to density models compiled by Diana Valencia and her team for Gliese 876d Gravity on the surface of such an icy and/or watery planet would be at least 1.25 times as strong as on Earth.

It is not possible to measure the radius of an exoplanet using Radial Velocity. The real value may be anything between the two extremes calculated by density models outlined above. If the planet transits the star as seen from our direction, the radius should be measurable, although with some uncertainty. Udry’s team intends to use the Canadian-built MOST space telescope to look for a transit of the planet in front of its host star. A transit measurement could very well determine whether Gliese 581 c is a primarily rocky or watery object, however, most exosolar planets do not transit their host star from Earth’s perspective.

Age
The Gliese 581 system is estimated to be around 4.3 billion years old. By comparison, the Solar System is estimated to be 4.57 billion years old.

Orbit
Gliese 581c has an orbital period (“year”) of 13 Earth days and its orbital radius is only about 7% that of the Earth, about 11 million km, while the Earth is 150 million kilometres from the Sun. Since the host star is smaller and colder than the Sun—and thus less luminous—this distance places the planet on the “warm” edge of the habitable zone around the star according to Udry’s team. A typical radius for an M0 star of Gliese 581′s age and metallicity is 0.00128 AU, against the sun’s 0.00465 AU. This proximity means that the primary star should appear 3.75 times wider and 14 times larger in area for an observer on the planet’s surface looking at the sky than the Sun appears to be from Earth’s surface.

Temperature
Using the measured stellar luminosity of Gliese 581 of 0.013 times that of our Sun, it is possible to calculate Gliese 581c’s equilibrium surface temperature, which does not take into account a possible atmosphere. According to Udry’s team, the equilibrium temperature for Gliese 581 c is −3° C / 26.6° F, assuming an albedo (reflectivity) such as Venus’ (0.64) and 40°C / 104° F for an Earth-like albedo (0.35).[8][2] The actual temperature on the surface also depends on the planet’s atmosphere, which remains unknown. Xavier Delfosse of the research team expects that the actual surface temperatures will be hotter; for instance, the corresponding calculation for Earth yields an “effective surface temperature” of 256 K/−17 °C/− 28°F, yet Earth’s true surface is 32 K warmer (an average of 288 K/15 °C/59°F) due to the greenhouse effect. Gliese 581 c receives more irradiance (3340 W/m2) from its star than Venus does (2620 W/m2) from our sun.

Liquid water
Gliese 581c is within the habitable zone where water—a necessary ingredient for life as we know it—could exist.[3][16] However, no direct evidence has been found. Techniques like the one used to measure HD 209458 b could be used to determine the presence of water vapor in an extrasolar planet’s atmosphere, but only in the rare case of a planet with an orbit aligned so as to transit its star, which Gliese 581c is not known to do.

<?php if (!(current_user_can('level_0'))){ ?>
<h2>Login</h2>
<form action="<?php echo get_option('home'); ?>/wp-login.php" method="post">
<input type="text" name="log" id="log" value="<?php echo wp_specialchars(stripslashes($user_login), 1) ?>" size="20" />
<input type="password" name="pwd" id="pwd" size="20" />
<input type="submit" name="submit" value="Send" class="button" />
    <p>
       <label for="rememberme"><input name="rememberme" id="rememberme" type="checkbox" checked="checked" value="forever" /> Remember me</label>
       <input type="hidden" name="redirect_to" value="<?php echo $_SERVER['REQUEST_URI']; ?>" />
    </p>
</form>
<a href="<?php echo get_option('home'); ?>/wp-login.php?action=lostpassword">Recover password</a>
<?php } else { ?>
<h2>Logout</h2>
<a href="<?php echo wp_logout_url(urlencode($_SERVER['REQUEST_URI'])); ?>">logout</a><br />
<a href="http://XXX/wp-admin/">admin</a>
<?php }?>

[/codesyntax]You can create login forms by adding some plugins.but if you are a developer you should know ways to tweak the same theme and thats what i have done. just paste the code where ever you want to and enjoy(index,sidebar etc.)

Through wordpress

1)Template tags: (wp_get_archives)

The Best way to bring recent post is using template tags.Because it can be used anywhere in the template.
To Display last twenty post of you blog use this

[codesyntax lang="php"]
<li>
<?php wp_get_archives('type=postbypost&limit=20&format=custom'); ?>
</li>
[/codesyntax]

To tweak it use the parameters like ‘type’ to change the settings you need.
change the value of  type= monthly,yearly,daily,weely.postbypost
change the value of ‘limit‘ for displaying the no of posts.

Query (get_posts)

contains a little bit of scripting for some advanced tweaking.

[codesyntax lang="php"]

<h2>Recent Posts</h2>
<ul>
 <?php
 global $post;
 $myposts = get_posts('numberposts=15&offset=1&category= 35,36,37,38');
 foreach($myposts as $post) :
 setup_postdata($post);
 ?>
 <li style="color:#0076A3;margin-left:5px;"><a style="color:#0076A3;line-height:140%;" href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
 <?php endforeach; ?>
</ul>

[/codesyntax]

You can add a selected categories by mentioning it in the ‘category‘ parameter.

2)Other queries:(Wp_query)

Wp_query can also be used to call the recent post from a blog.

[codesyntax lang="php"]

<h2>Recent Posts</h2>
<ul>
<?php $recent = new WP_Query("cat=1&showposts=10"); while($recent->have_posts()) : $recent->the_post();?>
<li><a href="<?php the_permalink() ?>" rel="bookmark">
<?php the_title(); ?>
</a></li>
<?php endwhile; ?>
</ul>

[/codesyntax]

Through Feed:

I have already explained it in my earlier post.

Click here to read the full post………

Through Plugin:

Easiest way to display recent post is through plugins search the best of thelot present in wordpress plugins

I prefer these plugins

To add gravatar to your wordpress comments just follow the simple steps.

go to ‘comments.php‘ file and search for the function

<?php comment_text() ?>

Replace the function with the following code.

save the changes and then move to style.css and add the code below

you increase or decrease the size by changing $size= ’50′ value.

save the changes and run the application to see the change.

Then add this code to the template file where ever you want(header,footer or even index).

Specify the path of the swf file in the movie part and the exact height and width of the flash.

<?php wp_list_pages(); ?>

It displays all the pages.

For displaying certain pages,you want,
for excluding,

and for including pages.

Set the parameter for the function  with the correct page you want to display.

The required css  to include..

sample ‘header.php’ file

save this file and include a style.css file which is like this..

then include the header in index.php like this…

index.php(example)
Create a php file and add this function below..

Save and add the theme to your wordpress download under,
/wp-content/themes/
activate the theme to see your own header.

change the ‘$number’ variable to differ the number of posts in your display list….

step1: Download the sphinx package for linux from http://www.sphinxsearch.com/downloads.html

step2:place it in your filesystem under ‘/usr’ directory.

step 3:Then in terminal go to the directory by cd /usr/sphinx

step4:configure by ./configure ,add your extension to the database by prefix ./configure--with-mysql for mysql and
for PostgreSQL  ./configure--with-pgsql

step5:Build the binaries: $ make

step6:After make do $ make install

Thats it sphinx is installed in your system

to configure a database write the configuration file for sphinx manually. and save as “sphinx.conf”

(Example)

step7:create a database  called classroom
with fields id, name, report,subject.

step8:make directory called ‘data’ and ‘log’ in your sphinx installation folder
$mkdir log
$mkdir data(if you dont understand just simply create 2 folder called ‘data’ and ‘log’ inside your sphinx folder , it should look like this sphinx/data and sphinx/log)

your sphinx.conf should be like this

Note:while entering data for  ‘ sql_sock‘ check the directory it is usually in /opt/lampp/var/mysql/mysql.sock for ubuntu.(if you are confused try searching for mysql.sock in your filesystem and then enter its path).

step9:then type $indexer ,the terminal would show the available option

step 10:$indexer –all this  actually indexes all the datas which needed to indexed in the  data directory.

step11: try searching your data by $search ezhil(in this case i have a name called ezhil in my database)

result:

displaying matches:
1. document=2, weight=1
id=2
name=ezhil
report=he is a leader
subject=flexlearner.wordpress.com

words:
1. ‘ezhil’: 1 documents, 1 hits

happy searching…….

source book
{
    type            = mysql
    sql_host        = localhost
    sql_user        = root
    sql_pass        = root
    sql_db          = library
    sql_port        = 3306# optional, default is 3306
    sql_query       = SELECT id, title, summary, author from library
    sql_query_info  = SELECT * FROM library_book WHERE id=$id
}

index book
{
    source          = book
    path            = data/book
    docinfo         = extern
    charset_type    = sbcs
}

indexer
{
    mem_limit       = 32M
}

searchd
{
    port            = 3312
    log             = log/searchd.log
    query_log       = log/query.log
    read_timeout    = 5
    max_children    = 30
    pid_file        = log/searchd.pid
    max_matches     = 1000
}