Wednesday, November 14, 2007

Club Nintendo Star Maker

When the spaceship affionda


session, at least occasionally, to the origins of this blog. Post
sc-sc-science today. Or how to remove always those twenty-five readers of this blog by Manzoni. Who wants to skip and can wait for hours of recreation: I can tell you is very long.
So do not wonder then ;-)))

Everything comes from the answer to the question: What is it and how the so-called gravity assist ? Well just yesterday

Rosetta had a second close encounter with Earth. I'm not talking nor my friend crashed to the ground or the crunchy roll (which, absurdly called Milan michetta ) unfortunately fell in the mud along with the salami: it is instead the probe launched in 2004 by ESA (European Space Agency) and to which Italy contributed to the establishment of special digital transponder on board. And before you ask, if it works and is flying is because not there I was.

The Rosetta mission is named after the stele that reveals the secrets of Egyptian hieroglyphics, because with this probe, we hope to uncover the secrets of comets, the oldest celestial bodies of the System Sunny.

operators have precisely maneuvered the probe to ensure that the Earth's gravitational attraction would provide a maximum thrust washer can, then you need to save fuel and arrive at your destination (ie the comet 67P/Churyumov-Gerasimenko in November 2014 four astronomical units away from the Sun Cheppalle, I get: 600 million km, so that is good?).

The moment of closest approach to Earth occurred November 13, 2007 at 21:57 CET as Rosetta in spite all'autovelox hurtled at a speed of 45,000 km / h (about 12.5 km / s) compared to Earth, flying over the Pacific Ocean, south-west of Chile, for un'altitudine di 5301 km. Sticazzi.

Comunque c’è una bellissima animazione qui .

L'incremento di energia acquisita aiuterà Rosetta ad attraversare una seconda volta la fascia di asteroidi, osservare Lutetia (il suo secondo obiettivo tra gli asteroidi) e infine effettuare l'incontro con la cometa.

Ma veniamo alla spiegazione: avete presente la fionda di Davide, che non era fatta da forcella ed elastici ma era piuttosto quella che nel medioevo veniva chiamata frombola ? Ecco, supponiamo di farla ruotare sopra la nostra testa e quindi di scagliare la pietra: essa partirà alla velocità cui stava ruotando (quando si dice partire per la tangen- ziale , Even at rush hour).
If I repeat the experiment by a speeding car (convertible, eh), the stone will have more speed than before that of the machine. The difficulty for us is the same, the increased speed at the cost of gasoline is wasted to make such a silly.

The thing is obvious to everyone, but who knows how it took the insight of the Italian scientist Giuseppe Colombo (every 500 years there is a Colombo with an intuition that changes history, and each point There is an intuition that Columbus used to stop the culprit) to understand that the same principle could apply the spacecraft, with significant fuel savings (aside: perhaps the Italian research funds cut them on purpose so much to us just three and a little snots' of string and go to Mars). And we can not bring on board all the fuel we want, because for every pound of weight should be sent into orbit to do half the oil tanker off the ground. What then, because what happens to oil lately, perhaps would agree as well.

Therefore, a probe that comes close to a planet will deviate from its trajectory due to the severity of it and moves away along a direction different from that of arrival:






If the planet was still, as long as the probe approaches would accelerate, then slow down and finally it should be at a rate equal to that approach. Just like when we overcome a bike off, then slow down and speed up down the next hill, and then left with the same speed at which we had arrived. But now, yet it moves, as he said another Italian genius, and in appropriate conditions the probe can be run at a speed greater than that with which they approached. Speed \u200b\u200bthat comes from the "push" provided by the planet, and is without consuming fuel. So the planet "grab" the probe, providing raises energy: By analogy with the example of stone, this mechanism is called a gravity assist.

But if nothing is created nor destroyed, although there is no meal aggratis , which has consequences for what? Answer: The planet slows its motion. At least in theory: do not think we will end up sooner or later cause the arrest: a case of ' huge difference between the mass of the probe and that of the planet, so it slows down in a negligible we can safely say that it continues to move as if nothing had happened (although the idea of \u200b\u200bsfruculiare even just the motion of planets and comets in the ass to those of astrologers and charlatans with their outlandish theories about the influence of celestial bodies, I am not a little amusement). A bit 'like trying to stop a truck to 130 km / h with an ascent of 40 km / h on the bumper: the ball bounces back to 170 km / h. Of course, to your face.

And yet to get the shooting.

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