August 5, 2011
April 11, 2011
Star disintegration : A massive interstellar explosion near a black hole
0 commentsMore @ NASA
November 14, 2010
Quantum Quest: A Cassini Space Odyssey
1 commentsMarch 10, 2010
Is Obama's space policy right?
0 commentsFollowing article comes from The Wall Street Journal
(http://online.wsj.com):
February 25, 2010
Trading the Moon for Mars
Obama's NASA budget has our space priorities right.
By Buzz Aldrin
In January, President Obama announced a new budget for NASA that would, newspaper headlines screamed, "Eliminate Funds for Manned Missions to the Moon." Instead, the budget proposes new missions in near-Earth orbit. It also directly challenges and empowers the private sector to push the envelope of human space travel, and implicitly puts America on track to perfect life support and other technologies that can be tested closer to home before embarking on more distant destinations in space.
Many said the president's decision was misguided, short-sighted and disappointing. Having the experience of walking on the moon's surface on the Apollo 11 mission, I think he made the right call.
If we follow the president's plan, our next destination in space, Mars, will be within our reach. Rich in potential resources—including water, an atmosphere, and oxygen in the soil—Mars invites human exploration and eventual habitation. But perfecting the technology necessary to succeed in our eventual journey is a wise first step. Empowering the private sector to carry crews and cargoes into orbit faster is a critical second step.
The new NASA budget makes sense for many important reasons. First, the president is signaling that this agency deserves the full support of this administration and Congress, even as priorities are sorted out and other budgets are cut. Second, getting long-range space flight right requires getting near-Earth orbit perfect. Third, forestalling the moon mission in favor of perfecting the technologies that will allow us to reach Mars within some defined period ahead is sound. We should not rush it and experience an avoidable tragedy.
Mars is the long-range objective for our space program. Just as deep sea exploration began with practice in our littoral waters, a successful Mars mission begins with near-Earth orbit testing. To get to the final stage, we must perfect all that we'll need for the journey. The president' budget and step-by-step approach helps do that, minimizing the risks and costs as we go.
The new direction that Mr. Obama has set in this budget is the kind of bold initiative we have needed for many years. Mankind must explore and America must lead—in all aspects of space exploration, not least manned space exploration. But we must be willing to embrace real vision and reach for Mars with the patience that leadership has always required.
As President John F. Kennedy said in his historic 1962 speech at Rice University, "We choose to go to the moon in this decade and do the other things not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills."
The same can now be said of missions for the permanent human settlement of Mars. Yes, there will be risks. But a great nation has always known the risks of exploration are far outweighed by the discoveries and better lives that exploration brings to our country. With this budget, the president is preparing us for a brighter American future in space. I believe he deserves our support.
March 1, 2010
De l'eau sur Encelade ?
Ce que vous voyez comme de la lumière c'est en fait des jets avec des particules de glace, de la vapeur d'eau et de composés organiques. Ces jets ont lieu dans de nombreuses fissures le long des fameuses "rayures de tigre" près du pôle sud d'Encelade, lune de Saturne. Plus de 30 jets individuels de tailles différentes peuvent être observées dans l'image et plus de 20 d'entre eux n'avaient pas été identifiés auparavant.
Cette mosaïque a été créée à partir de deux images à haute résolution qui ont été capturés par la caméra de la sonde spatiale Cassini qui avait survolé ces jets le 21 novembre 2009. La vue a été obtenue à une distance d'environ 14000 kilomètres d'Encelade et à un angle de phase de 145 degrés. L' échelle de l'image est de 81 mètres par pixel.
Les scientifiques du projet Cassini continuent d'étudier la question de savoir si les réservoirs d'eau liquide existent sous la surface de cette lune.