Become a fan of Slashdot on Facebook

 



Forgot your password?
typodupeerror
Check out the brand new SourceForge HTML5 speed test! Test your internet connection now. Works on all devices. ×

Submission + - A Glimpse Through a Cosmic Keyhole (quantamagazine.org) 1

An anonymous reader writes: A few weeks ago, I came across a preprint of a striking astronomy paper that none of my physicist friends seemed to be talking or tweeting about. The paper’s co-authors, Russ Taylor and Preshanth Jagannathan of the University of Cape Town in South Africa, had spent 300 hours observing a small patch of sky using India’s Giant Metrewave Radio Telescope. The galaxies in this particular patch had been imaged before with optical telescopes, but the long-exposure radio image caught the galaxies in a surprising act.

The image revealed 65 “active” galaxies, meaning that they have jets of material streaming out in two directions, probably powered by the supermassive black holes spinning at the galaxies’ centers. (The jets emit radio light but typically aren’t visible at optical frequencies, which is why they hadn’t been seen before.) Remarkably, the jets of about a dozen of the galaxies, concentrated in a subregion of the field of view, can all be seen pointing in the same direction. “You can visually see it,” said Richard Battye, an astronomer and cosmologist at the University of Manchester who was not involved in the work. The alignment “is definitely there.”

Comment Did I miss something? (Score 1) 314

"I met this man in Meghalaya, who has a solar set-up for his homestay. He mentioned that only the initial setting up costs you much," Deepika Gumaste, a travel writer told Slashdot. "But once you have set it up, the operating costs are not much and more importantly, the environmental costs also go down. Good on your pockets too in the long run."

Did this guy just extrapolate grid-sized solar capacity from one guy's home solar setup???

Submission + - Ask Slashdot: Anachronistic computational devices? 1

tgibson writes: For some time I have been thinking about designing and delivering a one- or two-credit course on the use of computational devices that are either no longer used or are given short shrift due to technological advances. Examples include the abacus, slide rule, and astrolabe. More exotic examples might include the Antikythera mechanism, the E6B flight computer or even archaeoastronomical sites. I would also like to have some of the simpler, unavailable tools 3D-printed for the students and incorporate them into activities.

Although I have been accumulating a list of such devices and other background material, I'm sure there are many "must-haves" I am unaware of. What anachronistic computational devices would be well-suited for such a course?

Comment Re:threatened to nuke America (Score 1) 192

The Tsar Bomba TEST yielded 50MT. That was because it was missing it's outer uranium boost blanket that would've made it dirty as sin but a full 100MT.

I quote:

The initial three-stage design was capable of yielding approximately 100 Mt, but it would have caused too much nuclear fallout and the plane delivering the bomb would not have enough time to escape the explosion. To limit fallout, the third stage and possibly the second stage had a lead tamper instead of a uranium-238 fusion tamper ...

Comment Re:Why only one (Score 1) 140

The oft-overlooked part of this is all of the infrastructure needed to manage the sats once in orbit. There are only so many earth stations and only so much TDRSS satellite bandwidth available.

Also, by the time a satellite is finished, technology has usually outpaced the onboard systems and made it illogical to duplicate the original sat.

Slashdot Top Deals

Forty two.

Working...