In a Sudoku puzzle, what is the minimum number of pre-filled boxes for a puzzle to have only one solution? |
- In a Sudoku puzzle, what is the minimum number of pre-filled boxes for a puzzle to have only one solution?
- How much energy is released by dropping a pen on a neutron star?
- Are light photons emitted by fire the same photons emitted by artificial light such as a light bulb or LED?
- What would happen if we had twice as many veins but they were half the size? (Same amount of blood, same size heart)
- Why does adrenaline make you stop feeling injuries?
- Does the rotation/spin of the earth reduce our feeling of gravity?
- [Psychology] What is the current understanding of how the Ferber method affects children's development when compared to other approaches to responding to babies?
- If an organ from a 50 year old is put into the body of a 20 year old, does any special considerations have to be made for the advanced age of the donated organ?
- Assuming a clear path, would it be possible for an object to orbit the earth a few feet off the ground?
- [Physics] How does current density affect the specific energy of an electrochemical cell?
- Where in a uniform sphere is gravity most strongly felt?
- Are there any critical phenomena where the timescale and lengthscale diverge identically with temperature?
- If photons can eject valence electrons from certain materials/elements, do new electrons replace the ejected ones? If so, how?
- What limits how hot a laser can make something?
- Why can't light coming perpendicular to my vision affect light that is coming straight to me?
- Gravitational waves not discovered?
- Can you count past infinite? And if you can, how?
| Posted: 02 Jul 2016 08:51 PM PDT |
| How much energy is released by dropping a pen on a neutron star? Posted: 03 Jul 2016 05:28 AM PDT Hi guys. Neutron stars fascinate me. Crushing the mass of 3 suns into a Manhattan sized ball of neutron soup is a mind blowing concept. Anyway it's been said that if you were standing on surface of a neutron star and you dropped a pen it would approach the speed of light as it hit the ground. it's been well over 15 years since I've crunched logs and sci notation and I can't get the units down right, so my question is how much energy would be released by a pen hitting the floor at near speed of light? Not sure how much a pen weights... 10 grams? Thanks [link] [comments]  |
| Posted: 02 Jul 2016 08:37 AM PDT Edit: This post has absolutely blown up and given me quite the insight on many things I didn't know. You've been quite helpful and to be honest my brain hurts a little. I did already know that that white light is made up of all colors of the spectrum but the majority of this thread is blowing my mind. Edit 2: You guys have been awesome. I learned a Shit ton and know that I've read through just about every graph link and explanation I've been provided. Happy fourth everyone. [link] [comments]  |
| Posted: 03 Jul 2016 07:32 AM PDT |
| Why does adrenaline make you stop feeling injuries? Posted: 02 Jul 2016 05:52 PM PDT Today, I read a few posts in an /r/askreddit thread that told how they did not feel their very major injuries (broken back and hip) until they woke up later in a hospital bed. Specifically, ones story was this: they went over a jump on their horse which they were training and lost memory at that point. Witnesses described them as cleaning their horse and driving home without ever noticing they broke their back. Why does adrenaline do this? Shouldn't it make you more aware of what's going on, instead of less aware? [link] [comments]  |
| Does the rotation/spin of the earth reduce our feeling of gravity? Posted: 03 Jul 2016 07:03 AM PDT Thinking about how when you spin things naturally move away and the concept of spinning large space stations for artificial gravity... If the earth stopped spinning would gravity double? Triple? [link] [comments]  |
| Posted: 02 Jul 2016 10:11 AM PDT Are there any reputable long-term studies on the subject? [link] [comments]  |
| Posted: 02 Jul 2016 12:22 PM PDT |
| Posted: 03 Jul 2016 05:08 AM PDT How fast would the object need to be moving? Would this be slower or faster than an object orbiting in space? [link] [comments]  |
| [Physics] How does current density affect the specific energy of an electrochemical cell? Posted: 02 Jul 2016 10:59 AM PDT I was reading a paper, and came across this: "attained specific energies of 303 Wh/kg cathode at 0.1 mA/cm2, 183 Wh/ kg cathode at 0.2 mA/cm2, and 76 Wh/kg cathode at 0.8 mA/cm2. The active material utilization achieved at these current densities was 94. 54. and 23%. respectively." I am confused, how does the rate of use of a battery affect its overall capacity? [link] [comments]  |
| Where in a uniform sphere is gravity most strongly felt? Posted: 02 Jul 2016 05:30 PM PDT |
| Posted: 02 Jul 2016 07:40 PM PDT For example, many critical phenomena (phase transitions, etc.) have a diverging lengthscale that goes as ξ ∼ (T−Tc)α where Tc is the critical temperature. The characteristic dynamics of this system will then scale as τ ∼ ξz ∼ (T−Tc)zα Are there any systems where z=1 , meaning that the static and dynamic divergences scale to the same power α with respect to temperature? [link] [comments]  |
| Posted: 02 Jul 2016 05:45 PM PDT |
| What limits how hot a laser can make something? Posted: 02 Jul 2016 10:48 AM PDT I know that, using the sun as a light source, you cannot make anything hotter than the surface of the sun. ΘΑ=ΘΑ and all that. Now, how hot can you make something with a hypothetical 50W blue laser? How is that energy absorbed by the material it is fired at? Is there a terminal temperature that it will reach, maybe until the spot itself is radiating 50W of energy as the laser comes in? [link] [comments]  |
| Why can't light coming perpendicular to my vision affect light that is coming straight to me? Posted: 02 Jul 2016 09:33 AM PDT As per my understanding, a candle burns yellow because it emits photons of the yellow wavelength and my eye detects those photons that are coming at me directly. However, if I shine a purple light perpendicular to my field of vision, intersecting what should be the yellow light, it does nothing to change the color what the candle appears to be. You would think that since it's all affecting the electro-magnetic field, there would be some kind of interaction that would either make the yellow appear purply or the purple to appear more yellow (should you be looking at the purple light directly). What's going on here? [link] [comments]  |
| Gravitational waves not discovered? Posted: 02 Jul 2016 09:29 AM PDT I was recently reading an article which claims that the gravitational waves discovery can be contributed to the milky way. "In the joint analysis, the researchers overlaid data recorded by the BICEP2 telescope at a frequency of 150 gigahertz (GHz) with data recorded from the same patch of sky by Planck at 353 GHz, a frequency at which almost all the polarized light comes from dust. (Planck also records polarization signals at lower frequencies.) The two data sets proved to be a match — the region in which BICEP2 found its strongest signal is the same place in which the Planck dust signal is strongest, indicating that the BICEP2 signal is due almost entirely to dust." Article link here : http://www.nature.com/news/gravitational-waves-discovery-now-officially-dead-1.16830 Any thoughts on this? [link] [comments]  |
| Can you count past infinite? And if you can, how? Posted: 02 Jul 2016 12:05 PM PDT |
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