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Comment: M-Theory and gravity (Score 2) 147

by blincoln (#47495577) Attached to: Can the Multiverse Be Tested Scientifically?

Ever since I read The Elegant Universe years ago, I've had a number of questions related to this (as I imagine many people have). This is the first time I've seen the topic discussed by professional scientists, though, as opposed to people like myself with a hobby interest in the subject or in science fiction (Alastair Reynolds makes use of it in one of the Revelation Space novels, for example).

For the most part, it seems like String/M-Theory is very difficult (at best) to test using technology we have access to at present. But because it includes the idea of gravity being a force which can travel between branes, it's seemed to me and a few friends of mine that this would definitely produce some interesting effects in the real world.

As the article discusses, there should be some subtle evidence of the effects of gravity from external sources on the large-scale structures of our own universe. I would think maybe even enough to at least partly explain "dark matter" and "dark energy", since those are basically the known matter in our universe behaving as if there were a lot more mass that we can't actually see (one set to hold relatively closely-spaced matter together, and the other to accelerate the expansion of the large-scale structures away from each other, if I understand correctly).

A simple flatland-style analogy for "dark energy" might be that our universe is a sheet of paper which is intersected by a universe which is wrapped around into a tube shape or a torus. The gravity of the mass in that second universe pulls objects in our universe toward it, so for the part of our universe in the "eye" of the tube, they tend to accelerate away from each other. That's a vast oversimplification, but I'm not a physicist :).

For "dark matter", the idea that's always stuck with me since reading The Elegant Universe is that maybe some/all of the most massive objects in our own universe - especially the black holes at the centers of galaxies - are caused by the same kind of cross-brane effect. If you have a bunch of matter clumping together in one brane/universe, and it exerts gravity which can cross into other branes, then it seems like it would create corresponding accretions of mass in other nearby branes. Basically, that what we perceive to be a roughly spherical/point object would effectively be the hyperdimensional equivalent of that same shape that would "pin" itself together across branes.

Where I see this as becoming testable (and I could be wrong - again, I'm not a physicist) is that if this were the case, there should be examples of anomalous astrophysical objects and events, where the mass we observe does not line up with effects we also observe. For example, a stable neutron star suddenly flashing into a black hole when it passes too close (hyperdimensionally, of course) to a large mass in another brane. Another example might be a star or planet whose mass can't be reconciled with its observed size - e.g. maybe there is a planet the size of our moon, but which exerts gravity as if it were made entirely out of a material ten times as dense as uranium.

I know that in the context of our own universe/brane, there's no way to pull matter out of a black hole (other than Hawking radiation), but assuming the "hyperdimensional singularity"-type thing I described above is accurate, would it be possible for the cross-brane components to separate (since they wouldn't actually be touching, just exerting gravity on each other)? If so, there might be even stranger observable effects, like neutron stars that "flash" into black holes, but then return to their former state when the mass in the other brane(s) is pulled too far away. IE they would "blink".

Comment: Re:Another materials article (Score 1) 33

by blincoln (#47384401) Attached to: Researchers Create Walking, Muscle-Powered Biobots

Seems like one could use this type of engineered muscle to power an electrical generator which would either recharge a battery or power an electronic device directly. Then you'd have an implanted electronic device which never needed to have its battery changed or recharged using external means.

If it burned enough calories, maybe it could even be sold for cosmetic reasons - eat all you want, and transfer the surplus charge from your implanted battery to an outside system via induction.

There isn't exactly a surplus of empty space inside the human body, but I imagine this type of system could also be used to pre-condition engineered muscle tissue or replacement hearts before they're implanted into their intended recipient's body.

Comment: Re:Meh (Score 1) 129

by blincoln (#46823615) Attached to: Lytro Illum Light-Field Camera Lets You Refocus Pictures Later

So your solution to the problem is that everyone should become a Sports Illustrated-grade professional photographer and shoot hundreds or thousands of photos at every event they go to so they can pick out the 3-5 that were actually in focus and properly composed?

I think I'm going to go with the light-field camera being the more realistic option.

Comment: Re:Not sending history to Valve (Score 1) 511

by blincoln (#46276065) Attached to: Gabe Newell Responds: Yes, We're Looking For Cheaters Via DNS

Most cheating involves modifying processes in memory, not the files on disk.

I do agree that it's really heavy-handed of Valve to ban players over DNS entries, though. What's to stop me from posting a page on some heavily-trafficked site with embedded image tags pointing to those systems (they may not load, since who knows if the cheat servers are even running web server components, but visiting machines will still cache the DNS entries), trying to get anyone who visits it banned on Steam?

Comment: Re:Humanoid robots are kind of dumb to me (Score 4, Insightful) 51

by blincoln (#45761291) Attached to: Japanese SCHAFT Takes the Gold at DARPA Robot Challenge

I believe the idea with humanoid robots is that if you have to deploy a robot into an unforeseen and dangerous situation, having a robot with a humanoid form means it's more likely to be able to do all of the things that a human could do, and get into all of the same places.

E.g. if you have a nuclear reactor emergency - especially in an older facility - most of the controls are going to be designed for a human to operate, like the valve wheels depicted in some of the challenges in this contest, and at least some of the building is only going to be accessible through doorways, stairways, ladders, and crawlspaces designed for humans.

It's the same with operating an arbitrary vehicle (another one of the challenges). Just about any vehicle that's going to be available in an ad-hoc situation is going to be built for use by someone with at least two arms and two legs, with hands that have opposing thumbs, and which is somewhere within 20-30% of 2 meters tall (or their eyes won't be able to see anything).

Sure, you could try to build all of your critical infrastructure in ways that would allow non-humanoid robots to operate it easily as well, but that doesn't take care of all of the legacy stuff that's out there, and will be out there indefinitely.

You could also build a variety of robots that are specialized to do one or more of those things without being humanoid, but that robot probably won't do very well in the other types of situations this contest is intended to simulate.

Once they work a *lot* better, and are intuitively controllable via telepresence, I can really see some commercial applications of this too. One or two telepresence androids available for remote use sitting in a datacenter would be better in some ways than having iLO cards in every physical server. Just about anything that involves a remote, un-staffed facility becomes a lot easier if your workers can "teleport" there by android instantly when something goes wrong.

Comment: Re:Chip and Pin (Score 4, Informative) 191

by blincoln (#45733537) Attached to: Target Has Major Credit Card Breach

Chip-and-PIN isn't perfect, but it's about a thousand times better than the archaic mag-stripe cards that are still in use in the US.

Mag-stripe cards are a relic of 30-40 years or more ago - similar to social security numbers - where your identification is the same as your authentication. It's a "secret name"-type system where as soon as you tell someone what your account number is, they can do whatever they want with it.

Mag-stripe cards can be cloned easily with a ~$100 reader/encoder that you can order from China on eBay (I have one - it's pretty neat). All you need to do is swipe the card through it once (or through a cheap reader, which you save the data from and then write to a card using the bulkier encoder later). AFAIK with Chip-and-PIN, you would need a lot more time with the card, some expensive hardware, and some reverse-engineering skills instead of just click-the-copy-button skills.

Also, AFAIK, with Chip-and-PIN, you can't clone the card solely by intercepting network or device-to-device traffic. You have to compromise the reader itself. If you can intercept unencrypted network traffic from a mag-stripe transaction, then at a minimum you've got everything you need to use that card fraudulently online, and depending on how bad the system is that's involved, you probably have everything you need to create a full clone of the card.

Comment: Re:don't connect everything to the internet! (Score 4, Informative) 191

by blincoln (#45733477) Attached to: Target Has Major Credit Card Breach

Who said anything about these devices being compromised by an attack from the internet? There are all sorts of ways to attack them indirectly:

- Compromise the system that manages them, then use that management system to push out compromised firmware or OS updates (depending on the device type - the newer payment terminals are often little Linux machines).
- Compromise the POS registers and capture the data there instead of directly on the terminals.
- Compromise the centralized back-end systems that Target uses for payment authorization. PCI-compliant retailers aren't supposed to capture full track data from the cards, but it might be possible to enable some sort of legacy mode that does just that.
- Compromise the network devices (routers, etc.) that the data is transmitted over. PCI only requires network-level encryption for transmission over untrusted networks, not internal corporate networks.

Etc. etc. Magnetic-stripe cards are a security nightmare, and everything that retailers do related to them is just a band-aid. We (the US) need to move to systems that use one-time codes - like chip-and-PIN - like the entire rest of the world is either in the process of doing or has done already.

Comment: Re:Infared Contact Lenses? (Score 1) 320

by blincoln (#44986945) Attached to: Two Years In Prison For Using Infrared Contact Lenses To Cheat At Poker

There's a problem with the theories all of you are coming up with - IR-pass filters appear black to the human eye. Unless casino staff were unable to see that there was something unusual about the guy with pitch-black irises, I'm thinking this is not what happened. In addition, unless the casino was lit with some sort of incandescent/halogen lighting or the sun, anyone wearing long-pass (visible-light-blocking) contacts would be blind in most indoor locations. Fluorescent and LED lighting put out basically zero near-IR light.

In addition:

- Near-IR really is infrared. It is "near" as opposed to "mid" and "far", not near as in "almost". It's the kind of infrared that remote controls used until RF (e.g. Bluetooth) became common, the kind that night vision goggles use, and the kind that CD drives (but not DVD or Blu-Ray drives) use for their lasers.
- Despite the arrangement of most spectrographic data arranging it to the right of visible light, all IR is longer-wavelength (lower frequency) than visible light.

Comment: Re:good news for NSA (Score 3, Insightful) 157

by blincoln (#44570357) Attached to: MIT Research: Encryption Less Secure Than We Thought

Actually, you're both wrong.

For certain types of encryption, you are right - a known-plaintext attack that easily reveals the key is a fatal problem for the encryption method. This is true of AES, for example. The converse is also true - currently, knowing the plaintext and encrypted values for an AES-encrypted block of data does not let an attacker determine the encryption key in a reasonable amount of time. It still requires testing every possible key to see if it produces the same encrypted block given the known plaintext.

Other types of encryption are absolutely vulnerable to known-plaintext attacks. I'm less familiar with this area, but certain common stream ciphers (like RC4) are literally just an XOR operation, and so if you know the plaintext and ciphertext, you can obtain the keystream by XORing them together.

"Trust me. I know what I'm doing." -- Sledge Hammer