In the Arms of M83
Big, bright, and beautiful, spiral galaxy M83 lies a mere twelve million light-years away, near the southeastern tip of the very long constellation Hydra. This cosmic close-up, a mosaic based on data from the Hubble Legacy Archive, traces dark dust and young, blue star clusters along prominent spiral arms that lend M83 its nickname, The Southern Pinwheel. Typically found near the edges of the thick dust lanes, a wealth of reddish star forming regions also suggest another popular moniker for M83, The Thousand-Ruby Galaxy. Dominated by light from older stars, the bright yellowish core of M83 lies at the upper right. The core is also bright at x-ray energies that reveal a high concentration of neutron stars and black holes left from an intense burst of star formation. In fact, M83 is a member of a group of galaxies that includes active galaxy Centaurus A. The close-up field of view spans over 25,000 light-years at the estimated distance of M83.
Superflares Are Not Possible
Says NASA:
Given a legitimate need to protect Earth from the most intense forms of space weather – great bursts of electromagnetic energy and particles that can sometimes stream from the sun – some people worry that a gigantic “killer solar flare” could hurl enough energy to destroy Earth. Citing the accurate fact that solar activity is currently ramping up in its standard 11-year cycle, there are those who believe that 2012 could be coincident with such a flare.
But this same solar cycle has occurred over millennia. Anyone over the age of 11 has already lived through such a solar maximum with no harm. In addition, the next solar maximum is predicted to occur in late 2013 or early 2014, not 2012.
I’m hardly surprised that the doomsday prophecies based on Mayan calendars continue to be refuted, but it is curious that there isn’t even enough energy in the Sun to cause a deadly superflare like the one in Knowing
more/via NASA
NGC 7380: The Wizard Nebula
From NASA APOD:
What powers are being wielded in the Wizard Nebula? Gravitation strong enough to form stars, and stellar winds and radiations powerful enough to create and dissolve towers of gas. Located only 8,000 light years away, the Wizard nebula, pictured above, surrounds developing open star cluster NGC 7380. Visually, the interplay of stars, gas, and dust has created a shape that appears to some like a fictional medieval sorcerer. The active star forming region spans 100 about light years, making it appear larger than the angular extent of the Moon. The Wizard Nebula can be located with a small telescope toward the constellation of the King of Aethiopia (Cepheus). Although the nebula may last only a few million years, some of the stars being formed may outlive our Sun.
Our Future in Space
This is one of the best videos I’ve seen this year. Phil Plait, Pamela Gay, Lawrence Krauss, Bill Nye, and Neil deGrasse Tyson, discuss the future of human spaceflight:
It’s long, but it’s definitely a must-watch.
In 1920 The New York Times Didn't Understand Vacuums
Back before spaceflight was cool, the New York Times published an editorial bashing Robert Goddard for apparently not understanding, as “any high school student would,” that “rockets don’t work in space:”
Topics of the Times
(“New York Times,” 13 January, 1920, p. 12, col. 5)A Severe Strain on Credulity
As a method of sending a missile to the higher, and even highest, part of the earth’s atmospheric envelope, Professor Goddard’s multiple-charge rocket is a practicable, and therefore promising device. Such a rocket, too, might carry self-recording instruments, to be released at the limit of its flight, and conceivable parachutes would bring them safely to the ground. It is not obvious, however, that the instruments would return to the point of departure; indeed, it is obvious that they would not, for parachutes drift exactly as balloons do. And the rocket, or what was left of it after the last explosion, would have to be aimed with amazing skill, and in dead calm, to fall on the spot where it started.
But that is a slight inconvenience, at least from the scientific standpoint, though it might be serious enough from that of the always innocent bystander a few hundred or thousand yards away from the firing line. It is when one considers the multiple- charge rocket as a traveler to the moon that one begins to doubt and looks again, to see if the dispatch announcing the professor’s purposes and hopes says that he is working under the auspices of the Smithsonian Institution. It does say so, and therefore the impulse to do more than doubt the practicability of such a device for such a purpose must be–well, controlled. Still, to be filled with uneasy wonder and express it will be safe enough, for after the rocket quits our air and and really starts on its longer journey, its flight would be neither accelerated nor maintained by the explosion of the charges it then might have left. To claim that it would be is to deny a fundamental law of dynamics, and only Dr. Einstein and his chosen dozen, so few and fit, are licensed to do that.
His Plan Is Not Original
That Professor Goddard, with his “chair” in Clark College and the countenancing of the Smithsonian Institution, does not know the relation of action to reaction, and of the need to have something better than a vacuum against which to react–to say that would be absurd. Of course he only seems to lack the knowledge ladled out daily in high schools.
But there are such things as intentional mistakes or oversights, and, as it happens, Jules Verne, who also knew a thing or two in assorted sciences–and had, besides, a surprising amount of prophetic power–deliberately seems to make the same mistake that Professor Goddard seems to make. For the Frenchman, having got his travelers to or toward the moon into the desperate fix riding a tiny satellite of the satellite, saved them from circling it forever by means of an explosion, rocket fashion, where an explosion would not have had in the slightest degree the effect of releasing them from their dreadful slavery. That was one of Verne’s few scientific slips, or else it was a deliberate step aside from scientific accuracy, pardonable enough of him in a romancer, but its like is not so easily explained when made by a savant who isn’t writing a novel of adventure.
All the same, if Professor Goddard’s rocket attains a sufficient speed before it passes out of our atmosphere–which is a thinkable possibility–and if its aiming takes into account all of the many deflective forces that will affect its flight, it may reach the moon. That the rocket could carry enough explosive to make on impact a flash large and bright enough to be seen from earth by the biggest of our telescope–that will be believed when it is done.
I wonder if the author suspected in his wildest dreams that Robert Goddard and Konstantin Tsiolkovsky would be remembered forever as the fathers of astronautics!
What makes the story positively ridiculous is that we knew that rockets would work in vacuums in 1920, as we had for centuries. As the Wikipedia article on Robert Goddard notes, “Unbeknownst to the Times, thrust is possible in a vacuum.[69]”. Citation 69 simply links to Isaac Newton’s magnum opus, the Principia, which was published in 1687. The proof in question is Newton’s third law of motion: “Every action has an equal and opposite reaction.” (Rockets could not simply not work in space—if you shoot out stuff in one direction, you will move in the other.)
The New York Times retracted the editorial in 1969.
via reddit