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Submission + - Another large Black hole in "our" Galaxy (arxiv.org)

RockDoctor writes: A recent paper on ArXiv reports a novel idea about the central regions of "our" galaxy.

Remember the hoopla a few years ago about radio-astronomical observations producing an "image" of our central black hole — or rather, an image of the accretion disc around the black hole — long designated by astronomers as "Sagittarius A*" (or SGR-A*)? If you remember the image published then, one thing should be striking — it's not very symmetrical. If you think about viewing a spinning object, then you'd expect to see something with a "mirror" symmetry plane where we would see the rotation axis (if someone had marked it). If anything, that published image has three bright spots on a fainter ring. And the spots are not even approximately the same brightness.

This paper suggests that the image we see is the result of the light (radio waves) from SGR-A* being "lensed" by another black hole, near (but not quite on) the line of sight between SGR-A* and us. By various modelling approaches, they then refine this idea to a "best-fit" of a black hole with mass around 1000 times the Sun, orbiting between the distance of the closest-observed star to SGR-A* ("S2" — most imaginative name, ever!), and around 10 times that distance. That's far enough to make a strong interaction with "S2" unlikely within the lifetime of S2 before it's accretion onto SGR-A*.)

The region around SGR-A* is crowded. Within 25 parsecs (~80 light years, the distance to Regulus [in the constellation Leo] or Merak [in the Great Bear]) there is around 4 times more mass in several millions of "normal" stars than in the SGR-A* black hole. Finding a large (not "super massive") black hole in such a concentration of matter shouldn't surprise anyone.

This proposed black hole is larger than anything which has been detected by gravitational waves (yet) ; but not immensely larger — only a factor of 15 or so. (The authors also anticipate the "what about these big black holes spiralling together?" question : quote "and the amplitude of gravitational waves generated by the binary black holes is negligible.")

Being so close to SGR-A*, the proposed black hole is likely to be moving rapidly across our line of sight. At the distance of "S2" it's orbital period would be around 26 years (but the "new" black hole is probably further out than than that). Which might be an explanation for some of the variability and "flickering" reported for SGR-A* ever since it's discovery.

As always, more observations are needed. Which, for SGR-A* are frequently being taken, so improving (or ruling out) this explanation should happen fairly quickly. But it's a very interesting, and fun, idea.

Submission + - Surado, formerly Slashdot Japan, is closing at the end of the month. (srad.jp) 1

AmiMoJo writes: Slashdot Japan was launched on May 28, 2001. On 2025/03/31, it will finally close. Since starting the site separated from the main Slashdot one, and eventually rebranded as "Surado", which was it's Japanese nickname.

Last year the site stopped posting new stories, and was subsequently unable to find a buyer. In a final story announcing the end, many users expressed their sadness and gratitude for all the years of service.

Comment Re:Space is hard (Score 1) 32

>SpaceX rockets failed repeatedly before getting it right

They didn't, though. There is a HUGE difference between test flights and production flights.

Falcon 1 scheduled several test flights. This where test flights, designed as such, and carrying accordingly mass-simulators, broken satellites, or a bloody wheel of cheese. Their first few failed, which was expected, and not a concern, as this are test flights. Then they reached orbit succesfully, and so they went into production. Their next flight was a production flight, and worked flawlessly too.

Then Falcon 9 came, which worked flawlessly on their first flight, and flew flawlessly for 5 straight years. They had ONE in-flight failure with 1.1, then absolutely none since FT. So 8 years of flawless launches, almost 200 of them too.

Comment Re:Cheap, efficient on-demand launch. (Score 3, Interesting) 32

Virgin Orbit offers expensive, inconvenient, unreliable launches.

For instance, Electron costs *half* of what a LauncherOne will cost you, and RocketLab is more reliable, has more launches under their belt, and offers a fantastic truly customer-oriented system.

The supposed advantages of air-launch aren't such. First of all, it's for the most part a lie. "It's just a plane, so we can launch anywhere". Well, except you do need pretty much all facilities except for a launch tower at your airport. And you need authorizations from everyone, from the FAA to the airport itself, local authorities, etc. Launching from another country? Even more bureaucracy. And it'll only be ok if it's a NATO country and the US gives the Ok for it (because ITAR). So all of those advantages evaporate fairly quickly.

If you want cheaper, and your orbit allows it, you can get on a SpaceX ridesharing mission. Anywhere from 300k to around 2 to 3 million for the max payload capacity that LauncherOne can handle. And you're launching on the most reliable rocket in history.

The problem with their last launch is a fundamental flaw, not necessarily on design, but on how they do things. Their processes are horrible. Sure, they aren't the same company as Virgin Galactic now, but they used to be, and they obviously inherited the same culture.

VO was already not very appealing, but now there are even more options, and more are coming. VO hasn't gone the way of Astra yet for the same reason BO isn't out of business: A big ego with big pockets behind it.

Comment Re:I don't understand why anyone is working on thi (Score 1) 40

Generally, I agree with your sentiment, but also "letting them get away with it" is a bad precedent. We've already seen similar efforts from microsoft, and from other manufacturers. Apple isn't the first, nor will be the last, to try and lock down a platform.

Breaking whatever BS protection they throw at it and doing what you want with the platform is exercising your right to use your own stuff however the hell you want. It's like the US flying over what China claims as the South China Sea. Basically, use it or lose it.

Comment Re:It's "Crew 6", not 6 crew. (Score 1) 45

That is correct. The first mission to carry humans for NASA wasn't a production mission, and so it was called Demo-2 (after Demo-1, which did everything but without people onboard). After that, Crew 1 through 6. So it's the 7th mission *for NASA*. In addition, they also flew Axiom 1 and Inspiration 4.

So, 1 manned demo mission, 6 missions for NASA in the main contract, "Crew" series, 1 for Axiom, 1 private, for a grand total of 9 missions with crew onboard so far.

Comment Re:The cure may be worse than the disease (Score 1) 110

Frequency response is all about spikes in demand or more often tripping generators. I can't talk too UK figures but for ireland peak demand is around 6000 MW and a large generator is arounf 420 MW and they do trip from time to time.

The Grid has genrators all in sync and the frequency is aimed to be at 50 Hz. When you lose a large generator the load is transfered to the other generators and they slow down , when they slow down this reduces the power on the grid increasing the load on the generators which slow down and unchecked spirals out of control and the grid crashes and then comes the long hard process of restarting the grid. This is extremely rare but the potential is there. The frequency is continually monitored and at a frequency of 49.8 hz approximately this will trigger automatic response This may include Battery sites releasing power to the grid, demand sites such as large frozen food distributors (basically removing demand is effectively the same as increasing generation but faster. This is the intially front line response and occurs within the second. Further power sources will kick in as needed. The short run generation can run for up to 3 hours usually which is enough time to being online long run generators (these can take up to 2 hours to ramp up from a warm start).

You can't really predict when a generator is going to trip out but the national grid is generally ready for it. Even texas is better prepared now.

There is flexibility you can over supply to a degree and if you turn on power and the demand is too high you may get another trip within a second of the power returning. Domestic consumers don't individually contribute that much and the grid has a pretty good idea of how much powers going to be needed to a particular sub-station. Grid operators are skilled and most of the time rarely have disruptions that reach the end consumer.
                   

Comment Re:The cure may be worse than the disease (Score 1) 110

People are going to recharge battery packs when the power returns but it will not create a peak as large as typical peak time demand which is when blackouts are liable to occur. So they will be recharging and at the same time generators will be ramping down just a bit slower than usual.

It's not going to be the same area's getting powercut either. So if you do lose power due to a shortage of energy in the grid it will likely be somewhere else that loses power the next time. For London, Birmingham Manchester Sheffield they will probably see more curtailment than other places but thats because they are the largest population centres using most power. It will be distributed around as there is a limit to how far you can shift supply around the grid.
   

Comment Peak demand is 4 to 8pm (Score 2) 110

Hi most of the day there shouldnt be a problem, peak demand is around double of the off peak so off peak there are generators either stopped or at minimum production (it's a lot easier to ramp up than start up). The UK and Ireland have a fair amount of wind generation available. For example in Ireland yesterday about 72.5% of the electricity generation was from renewable energy, still about 18% was from gas fired generators.

So the main problem time will be between 4 to 8pm with low wind generation. So if it looks like its going to be a miserable day chances are you won't be sitting in the dark with no electricity. The colder the day the more power will be needed at a rough guess a 1 degree drop in temperature will require an extra 750 MW of supply in the UK. A typical gas fired power station might be 420 MW.

There is a daily cycle of power usage with peak demand being about twice that of off peak. so off peak there are a lot of generators sitting idle that can be brought online and the wholesale price will be low at peak its the otherway round and there isn't much to spare. There is some reserve generation it's typically about the size of the 2 largest generators. so if the biggest two have say 1500MW between them there is usually backup of 1500MW this is standard practice in Australia but most grids will be similar.
Renewable energy is a great thing e.g in ireland yesterday i saw 72.5% of electricity production was renewable but on other days it can be as low as 1% (most typically in the summer when the weather is nice).

There are going to be days where the supply will be at risk, the industrial users are already looking at reducing usage during peak hours, In Ireland some industrial users will be subject to manditory demand reduction. Individual households can play thier part too by reducing their usage at peak times. Obviously one of the big uses of electricity at peak time is cooking but you could mitigate that by slow cooking during the day meaning you can have a hot meal ready when you walk in the door and avoiding peak electricity usage.

For computer users we can run laptops on battery over the peak time. Apples introduced smart charging to iPads in IOS 16 for USA initially so your iPad will try to charge when there is more renewable energy on the grid. Little things can help as there are a lot of us.

If you have a UPS have an Led lamp plugged in at around 6 watts it should easily run for the 3 hours of a black out. You might do the same for your router broadband companies will usually have backup power on thier networks.

Reductions in peak usage are going to be critical. When demand is high then the less gas fired generators running the better to avoid blackouts. The more we shift demand to off peak when renewable energy is available the better. E.g yesterday when we had that 72.5 % renewable energy on the grid as demand started to pickup so did the amount of Wind generation we were basically using the maximum amount of Wind on the grid that allows for grid stability, which implies there were some curtailments of Wind generation during the earlier hours as Wind generation moved closer to the expected availability. That was essentially energy going to waste.

It's basically going to be a learning experience for the general public, but the simple answer is reduce your peak hour electricity usage. It doesn't mean you have to wear a hair shirt and shiver but being a little smarter when you choose to use it.

Comment Re:for the price apple charges for storage they sh (Score 1) 45

To be fair i agree.

It's worth considering the difference roughly on my M1 mini the internal drive is twice the speed of the one on the Air 256GB Model, However the Samsung 1 TB T7 drive which lives attached to my M1 mini is about 4x slower than the internal drive or about half the speed if attached to the Air. The speed of a Sata interface is slower than the Samsung which is way faster than any mechanical HDD.

So I don't think you can say the SSD in the Air sucks , it's just not as fast as it could be.
On a more practical side of things 256 GB is a pretty small drive. Just loaded with applications on my mini, i have about 82 GB free and thats with all my data moved to my T7 it's closer to 20GB free normally. Which is not enough. If I was buying again I would buy the 512GB model. The 1 TB model would allow me to keep more on it but that goes against the principle of keeping archived data off that machine I have nas storage for that. which is backed up.

The Ram difference between 8 and 16 GB isn't a huge difference in most circumstances.

The next stage up is an M1 pro and then the M1 ultra models which really means going to the Studio models. The M1 pro models are probably the best bang for the buck, the Ultra's are faster but not twice as fast.

For me an M1 pro makes sense as i am not paying myself to work on it. If I were say Disney then the Ultra works out better if it's making the operator more productive. Thats the real expense wages, not the machines.

You could also argue that a PC that outperforms the Ultra would be a better option for Disney if the operator would find it a better machine to work on.

Personally I find the Dell i use for work loud and obnoxious, my boss isn't going to buy me a mac even though there is nothing running on the Dell that I couldn't run on a Mac.

So yes it's a poor choice on the part of Apple to put a slower SSD on the 256GB models, it's also a poor choice to buy the 256GB models and it's also a pain that its much faster to be able to buy a 256GB version and takes a few weeks to get the higher capacity versions.
           

Comment Re: I guess they didn't get the memo... (Score 1) 79

Well one thing they could do is export power. Which allows you to produce more safely. So it may have been they produced enough to power the UK's requirements with renewable and then exported the excess generated by conventional. I don't know the UK grid code so they may allow more on it's generally going up year on year.

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