so cute!

ok, i'm not usually this cheesy, but i really find this photo so cute!

it shows the satellite Herschel reflected in the mirror of the satellite Planck, which will (hopefully!) be launched next week, sharing the same rocket. that's why i actually found the picture totally sweet!

Herschel will observe the sky in the infrared, whereas Planck will scan it in the microwave, focussing on the CMB (cosmic microwave background), ie. the relic signature coming from the big bang.

ok, maybe it's a bit confusing... if infrared and microwave don't tell you much, check the next post for clarification. and check this blog soon for more about the CMB and Planck...

Image credits: ESA

the unbearable expansion of the universe

i just realised it's exactly 80 years now that Hubble found out we live in an expanding universe. yes, the galaxies all move away from each other, just like the points in this cute vintage photo do, as space itself is expanding. but i don't know how widely known this fact actually is. sometimes people ask me "since you're an astronomer, tell me, do you believe in the big bang theory??" like if it was a choice to believe in it or not! hell yes, this is my answer! true, it was a controversial topic, but those were... the 60's!! i mean, i reckon it IS a theory, and science wouldn't go on if theories weren't to be proven wrong from time to time, but up to now, with the experimental data collected so far, there is no other competing explanation at all. sure, the expansion is probably accelerating, and whatever is driving the acceleration, we almost know anything about that. true. but the expansion is a fact. people, deal with it!!!

Image credits: Life Magazine

developing astronomy globally

one of the key ideas of the International Year of Astronomy is to point out the contribution of astronomy to development.

in this context, it has just been announced that there will be grants available for projects related to the development of astronomy all over the world, especially in those regions that do not already have strong astronomical communities.

i thought it's an interesting opportunity, although i have no particular idea in mind and i have no experience whatsoever in planning such a project. so i thought i'd advertise it, at least...

the grants amount to 1,000 euro each, and the call for proposals can be found at the following address:

www.developingastronomy.org

Deadline: April 3rd, 2009
Watch out: deadline is next week!!!!

Note that, although this funding is aimed specifically at "developing countries", exceptions with appropriate motivation will be accepted - the main concern simply being who the beneficiaries would be.

Into the clouds where stars are born

Looking at the sky in the daytime, weather permitting, it is possible to see the Sun, the star which provides us with light and heat, thus making life on Earth possible. Looking at the sky during the night, one can see millions of stars: the firmament is abundant in large and small suns, located here and there in our galaxy, the Milky Way. Looking further away, with the aid of a binocular or a telescope, it is possible to perceive other galaxies, each of them containing from tens of millions to hundreds of billions of stars. Stars, stars, and even more stars. Where do all these stars come from? How did they form? They all derive from a mixture of gas and dust, known as interstellar medium, which is another important component of galaxies. The interstellar medium is rather homogeneous, but regions occur where the gas is particularly dense: it is exactly in these clouds, or nebulae, that stars are born.

When the gas within a nebula is so dense that its pressure cannot balance its own weight, the so-called gravitational collapse begins: the cloud starts breaking down into small fragments, which keep contracting and become rotating spheres of gas, increasingly denser and hotter. Collapse continues for a long time (up to a million years), until the temperature achieved within each “sphere” is so high that nuclear reactions set it, turning hydrogen into helium and producing energy: the gas “sphere” has now become a star. From the collapse of a single nebula, hundreds to thousands of stars with different masses are formed: the most massive ones will only live a few million years, whereas the smallest ones will go on burning for billions, even hundred billions of years.

This image of the Eagle Nebula is an example of a “stellar nursery”: the elongated structures visible in the centre are huge pillars of gas and dust, larger than our own Solar System, where stars are born. The bluish light permeating the central regions of the nebula comes from the first, young stars which formed: with their energy, they heat up the surrounding gas, thus making the formation of new stars even more likely. This image, obtained with the telescope on Kitt Peak in Arizona, USA, has an extremely high resolution, which allows to study star formation in detail; however, the Eagle Nebula can be observed even with a binocular, in the constellation of the Serpent, visible from Europe from May to September. New stars are formed all the time: in order to see them, we only need to lift our eyes up to the sky.

In the image, the Eagle Nebula, an open window onto the processes of star formation. Credits: T. A. Rector & B. A. Wolpa, NOAO, AURA.

Translated from Il Denaro, 12.02.2009

In search of the ideal site for astronomy

or: why is it convenient to build observatories on a volcanic island or a desertic plateau?

One fifth of the world population can no longer enjoy the sight of the night sky with the naked eye: close to urban and industrial areas, light pollution allows one to see only a few stars. It is a well known fact: anyone can perceive it, whenever looking up to the sky. If asked “which is the ideal site for astronomy?”, many would answer “far away from big cities.” Right, but not enough. Because escaping from light pollution is not the only problem to handle, in this case.

The key instrument in astronomy is the telescope. As the name itself says, its purpose is to look at objects which are located far away. In order to observe distant stars and galaxies, a telescope has to catch as much light as possible: this means that very large mirrors (currently with diameters of order 10 m, but up to 100 m for future generations) and very long exposure times are needed to achieve a good image. Unfortunately, before reaching the telescope, the light rays coming from stars and galaxies have to pass through the atmosphere of the Earth. Here, the cosmic light interacts with the turbulent atmosphere, thus losing track of much information about the objects (stars or galaxies) it comes from.

The atmosphere is not static nor homogeneous, but extremely turbulent. At every instant, a star or galaxy produces a slightly different image, according to the varying characteristics of the portion of atmosphere overlooking the telescope. A long exposure, needed to capture as much light as possible, is a superposition of the individual images obtained in several, consecutive instants. Because of atmospheric turbulence, the image resulting from such a superposition is blurred: this phenomenon is referred to as seeing.

It goes without saying that modern astronomy needs accurate and precise images, and the limiting effects due to the atmosphere have to be taken under control. Hence, in the last decades telescopes are being built in dry regions, preferably at high altitude, close to oceans or deserts, so that the surrounding air temperature is as constant as possible and the turbulence minimal. This is the reason why the ideal sites to build cutting-edge astronomical observatories are volcanic islands, such as Hawaii or the Canary Islands, and desertic plateaux, such as the Atacama desert in Chile.

An even more radical solution to remove the effect of seeing is a telescope orbiting around the Earth, outside of the atmosphere: though rather expensive, this formula has already been pioneered with the Hubble Space Telescope, and is the subject of several projects for the upcoming future.

---------

The photo, taken by Bobb Tubbs, shows the European telescopes in La Palma, on the Canary Islands: at an altitude of over 2,400 m, the observatory is higher than the clouds and the seeing is one of the best in the world.

Translated from Il Denaro, 22.01.2009

happy year of astronomy!

well, this blog didn't turn out to be a great success, i didn't really write a lot and stuff... lack of time, lack of ideas. whatever. the science magazine exercise idea was probably too ambitious, time-demanding, whatever...
but this year's the international year of astronomy, so i'll try to blog more, at least about astro stuff...

and if you want to celebrate the year of astronomy, visit www.astronomy2009.org and enjoy it :)

Energy comes from dancing!

last weekend i organised an anti-xmas-stress party (check the poster out: i made it! and am so proud of it!) with some people from the Weltladen, the fair trade store here in Heidelberg, and the dj there told me about a brand new club in the Netherlands where they are trying to use sustainable technologies, like that they produce electricity from the energy of the people dancing... how cool is that?? i was super excited, as i am always whenever i hear about energy that is conserved and reused in a clever way, and not only dissipated! so i started looking for info about the whole business, and i found out a lot of stuff...

the club is called Watt, it opened 3 months ago in Rotterdam and it's the first sustainable dance club ever. first, there is a special dance floor which makes use of the piezoelectric effect: some elements, crystals like quartz, if deformed or compressed are able to develop a potential difference, which can be plugged into a circuit and directly transformed into electric energy! which means that the more the people dance in the club, ie. the better the party is, the more energy is produced, and you can directly see it in the light show of the club itself! it clearly has a tiny energetic efficiency, but still it raises awareness about energetic issues, plus the club is sustainable in so many other aspects, from the refillable cups to the spectacular toilet where the flush water comes directly from the rain collected on the roof... for more info check out the website of the company (Sustainable Dance Club) or - if you trust me! - this article i recently wrote (in Italian...)

and now i want to go there and have a look, dance it out, produce some positive energy - and maybe take it along with me, i feel i need some...

Image credits: Mike Nolte & Giulia Melloni