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The Milky Way Is Much Less Massive Than Previous Thought

buback Re:Is this surprising? Twice as many stars (119 comments)

*2y dark matter mass to our y dark matter mass*

It would be 18y dark matter to Milky Way y matter.

about three weeks ago

The Milky Way Is Much Less Massive Than Previous Thought

buback Re:Is this surprising? Twice as many stars (119 comments)

So then really what they are confirming is that inference; that matter and dark matter are in a 1/9 ratio, and that if our galaxy has x stars and Andromeda has 2x stars, then Andromeda will also have 2y dark matter mass to our y matter mass.

That seems to be a more interesting finding.

about three weeks ago

The Milky Way Is Much Less Massive Than Previous Thought

buback Is this surprising? Twice as many stars (119 comments)

I've been taught that Andromeda has approx. 2x as many stars as the Milky Way. I learned this years ago, as far as i can remember.

Is it really surprising news that a galaxy with twice as many stars is twice as massive? Were these researchers just fact-checking?

about three weeks ago

Ode To Sound Blaster: Are Discrete Audio Cards Still Worth the Investment?

buback Creative can suck it. (502 comments)

I'm still bitter about Aureal.

about a month and a half ago

Moon Swirls May Inspire Revolution In the Science of Deflector Shields

buback Cosmic rays (76 comments)

Protecting from solar radiation is great, but i understand that the greater threat is cosmic rays. Solar radiation is somewhat easy to block, because you just put a light element shield, like hydrogen tanks, between the astronauts and the sun.

Cosmic rays are much harder to shield from because they are so high energy. They also come from everywhere, so require a omnidirectional shield.

about 2 months ago

Greek Government Abruptly Shuts Down State Broadcaster

buback SUVs (230 comments)

*cough* USgasolinesubsidies*cough*

about a year ago

Australian Police Move To Make 3D Printed Guns Illegal

buback counterproductive (551 comments)

3d-printing of guns: the quickest way to create legislation regulating the sale of bullets.

about a year ago

Solar Panels For Every Home?

buback Re:Flooded batteries (735 comments)

you were also missing half your roof. By your logic, you shouldn't put a roof over your head because a tornado might damage it.

PS. Homeowners insurance will cover and replace the solar panels that are damaged.

about a year and a half ago

Solar Panels For Every Home?

buback Re:Don't Strong Storms Eat Solar Panels? (735 comments)

If a tree* lands on your roof, solar-panel covered or not, you've got enough problems. But that's what homeowners insurance is for.

*or anything heavy enough to break a solar panel

about a year and a half ago

Solar Panels For Every Home?

buback Re:Extremely expensive (735 comments)

As you say, better generators cost more, and the power they generate is significantly more expensive than grid power. You would need to have a lot of power outages and spoiled food in order to break even on the cost during the usable lifetime of the generator.

A $2-3k generator and the cost of instillation is about 30% of the equipment costs of a solar installation, and the equipment is getting cheaper all the time (labor costs are flat or increasing). And a solar installation will pay for itself half way through it's warranted lifetime (about 1/3 of the way through it's usable lifetime).

about a year and a half ago

Apple Gets the Importance of Packaging; Why Doesn't Google?

buback Re:Ouch (639 comments)

Well I don't see what's so weird about displaying them on a bookshelf or table. Maybe with a nice tablecloth on top, and some candles and incense.

It's also a good place for me to put my sacrifices and to focus my prayers

more than 2 years ago

Intelsat Signs Launch Contract With SpaceX

buback Re:This is the exciting bit. (167 comments)

I think the pintile injector they are using, while not "new," is still exciting. This is old technology that hasn't been used much for first stage engines, in the US at least.

The pintile injector probably allowed such a safe and rapid shutdown during the first launch attempt.

more than 2 years ago

How Would Driver-less Cars Change Motoring?

buback Re:Ending congestion? (648 comments)

Yeah they would. Imagine perfect, zipper-like merging at highway speeds, and merging into a single lane to route around accidents, road work, or freight. The cars can all break and accelerate as one, and cars with equal acceleration/deceleration would be grouped together.

There is no lack of capacity on American highways. We could even reduce the number of lanes in each direction to two if everyone had driver-less cars.

more than 2 years ago

University of Florida Eliminates Computer Science Department

buback Re:The Department of Redundancy Department (628 comments)

Yeah because the primary purpose of a university is to make a profit. Sure, in the past the athletics programs were there for the benefit of the student body, but now it's the scholastic programs that are there for the benefit of the fans.

more than 2 years ago

Ask Slashdot: Home Testing For Solar Roof Coverage?

buback Retrofits aren't usually cost effective (85 comments)

I took a solar installer class, and learned that it's usually not cost effective to retrofit a house. Few houses have the proper size roof at the right angle to maximize efficiency. If there are trees in the way you can't cut down, just forget it.

but lets assume you want to find out anyway. well, you first need to look at how much power you use, because it will impact the size of installation you'd need. add up everything that draws electricity in the house. You'll probably find you need a much bigger array than you have roof space.

Now, that will be the size of the array at optimum efficiency. you'll have to subtract out all the efficiency losses for incorrect angle and shade, and add extra panels in order to get you back up to your needs.

I'm assuming you need certified installers in Floria because of the hurricanes, plus you'll need to get an electrician to install the inverter and breaker boxes, and probably a second electrician from the electric company to wire it up to the grid. If Floria has installation rebates, you'll need to do everything up and up in order to get your rebate.

So, first thing first: find a way to reduce your power draw by at least 1/3. it'll start saving you money now, plus you'll need a smaller array if you do commit to installation. it's much cheaper to start with efficient appliances and adequate insulation than it is to overcome it with more solar panels. Panels are getting cheaper, but labor costs are at least half of the costs. and while equipment costs go down, labor costs are flat or rising. If you build a house, build it with solar in mind and you'll save a ton of money up front, and you'll break even much much sooner.

more than 2 years ago

Electric Rockets Set To Transform Space Flight

buback Re:Electric Rockets Really? (114 comments)

Electric engines would either use solar panels or RTG for power, not batteries. Hell, they'd use fuel cells before they used batteries. any of these options are much much lighter than normal fuel, but even if they were equal for certain sized payloads, electric engines are much more efficient, so as payload mass increases, fuel mass scales at a much smaller rate.

more than 2 years ago

EPIC Sues FTC Over Google's Planned Privacy Changes

buback Re:EPIC (100 comments)

Meanwhile: Facebook changes it's privacy policy for the 20th time since the announcement of google's policy change.

more than 2 years ago

NASA Studying Solar Powered "Space Tugboat"

buback Casamir effect thrusters? (86 comments)

Do you mean VaSIMR?
Or Hall Effect Thrusters?

And Ion Thrusters of various types have been used as primary propulsion n space successfully ever since Deep Space 1. They've been used for satellite orientation and station keeping for decades. They are vastly more efficient than chemical thrusters, reducing the amount of propellant you need to carry, and therefore reducing launch costs.

more than 2 years ago

California State Senator Proposes Funding Open-Source Textbooks

buback Feynmans ghost approves (193 comments)

I'm sure if Richard Feynman were alive today he would be a very vocal proponent of OS text books. In fact, I'm sure he'd probably spend an inordinate amount of time editing them himself!

more than 2 years ago



Blue Origin breaks its silence (a little)

buback buback writes  |  more than 4 years ago

buback writes "Jeff Foust of talks to Blue Origins Gary Lai, discussing the past and future of Blue Origin, and giving tantalizing clues about their New Shepard LTVL craft.

"Goddard, the gumdrop-shaped prototype that flew in late 2006 and 2007 at Blue Origin’s secluded test facility in Culberson County in west Texas, may not offer clues on what the full-fledged New Shepard will be like, he cautioned. “That is not necessarily what the operational New Shepard vehicle looks like,” he said. Goddard was useful, though, in testing out operations of a VTVL rocket. “One of the main reasons for flying Goddard was to learn how to take a vertical-landing vehicle that uses the same propellants that our operational vehicle uses and learn how to fly that and turn it around in a very rapid manner,” he said. “Most of our lessons learned were in the operational area.”
the space review articles was published February 22, 2010"

Link to Original Source


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