Sensei

There is no perfectly transparent medium. It's just a matter of how many meters, or kilometers, we're talking about. If you point laser to water, you can see laser beam. It means that some photons from laser beam have been reflected from water molecules or contamination present in it.

Point light source, in this case star, is (typically) emitting photons in the all directions equally. Therefor power per area unit (in frame of reference of star) is given by equation: [math]P = \frac{P_0}{4\pi r^2}[/math] P0 is initial power of the star, P is power in watts per area unit at distance r. Spaceship, observer, is flying toward, or reverse, to star emitting these photons. In one second spaceship will travel some distance, but in the same time P in the above equation will change slightly because r will change (from r0 to r1). [math]P (r_0) = \frac{P_0}{4\pi r_0^2}[/math] [math]P (r_1) = \frac{P_0}{4\pi r_1^2}[/math] Periodical change of brightness can be used to measure distance to some distant star. Because of rotation of the Earth around the Sun, one day of year, Earth is ~ +150 mln km closer, half year later it's ~ 150 mln km further away from distant star. Giving you [math]\Delta r[/math] = ~ 300 mln km difference year-to-year.

You also need to take into consideration change of distance from point light source to observer using inverse-square law. https://en.wikipedia.org/wiki/Inverse-square_law

There is no bugs free programs, there are only ones nobody found bugs yet...

If people don't report bugs, to software developers, they will remain. Even remain forever, if nobody bothers reporting them (or reporting them not to authors of software, like in this case, but to some unrelated community, complaining on forum)..

Distill them, and try again whether you have the same results..

Nope. You misinterpreted what I said, and put my words upside-down.. What I said you should read: "C'mon, they ("D.Trump and his crew") are deniers ("in climate change") because they're ignorant.. See their ("D.Trump and his team") age- they are 70-80+ years old grandpas. They ("D.Trump and his fellows") don't understand anything from the modern world."

You know.. to be able to make sequel.. I urgently ask you to write for us energy conservation calculations of fusion of two protons..

Precisely..

Missing energy is supplied by cosmic rays, mostly from the Sun.

After removing some unique posts from threads, entire threads would be disrupted, and stopped making sense.. Quotes of member, deleted as well? And replies to replies as well? Nope.

You took my post personally.. Knowledge gained in the school of statistical person is decreasing after leaving school (but life experience is increasing, and knowledge/experience in the area he/she is working for living is increasing). Just percent of people (scientists, intellectualists etc. unique personalities) are trying keep up to date with current knowledge of human kind. Their children, and grandchild, are learning new, modern things. Majority of people, the peak of their knowledge they have in school. Well, make a test. Get modern school books (physics, chemistry, biology etc.), and read them. Make tests they contain, to check how much do you still know and remember from them. Test knowledge from books on your dad, and grandpas, giving them questions from books..

Reactions which require external source of energy.. ?

BTW, just a thought, quite cynical to be honest, natural disasters such as hurricanes, flooding, fire, etc. are one of the best things businessman-real estate developer can dream about.. Constant flood of orders every year for rebuilding ruined houses and buildings, especially interesting if paid by government..

C'mon, they are deniers because they're ignorant.. See their age- they are 70-80+ years old grandpas. They don't understand anything from the modern world. Times when the wisest and the most knowledgeable people in the village are grandpas and grandmas, are long time gone. Regardless, climate change is human-made, or it's f.e. natural increase of power of the Sun (when it'll be turning to red giant and burning Helium-4 more extensively), it's in the best human interest to "do something", and f.e. prevent higher radiation of the Sun by placing mirrors in the cosmic space between the Sun and Earth, to decrease radiation.. and being able to remotely control it when needed.. Without such devices this planet will vaporize and sterilize from living organisms much more quicker.. I would split deniers to "denying human-made climate change but accepting climate change" and "denying any climate change".

Ehem.. Decay of neutral pion [math]\pi^0[/math] releases ~ 135 MeV, two gamma photons..

Check out how to perform example mass-energy conservation calculation in high energy physics area, during relativistic particles collisions: http://galileo.phys.virginia.edu/classes/252/particle_creation.html Lab-frame is Earth frame-of-reference. One beam of protons accelerated to relativistic velocities, in particle accelerator like CERN/LHC, hitting stationary protons/atoms. Center-of-mass frame is special FoR in which either particle moves. After collision, new particles pops out of existence for a fraction of second (if they are unstable).. Then they decay, annihilate, fly away from detector (if they're neutral like neutrino/antineutrino)..

Lucky Janiv..

Very good idea. Slightly correction needed.. ~ 4.184 J/K*g * 1000 g * 100 K = 418400 J / c^2 = ~ 4.65 * 10^-12 kg = ~ 4.65 * 10^-9 g

What power electric heater? What power laser? Imagine, you have electron with 230 eV kinetic energy flying through wire. It decelerates in the wire which has high resistance (230 Volts electric heater), and gives its kinetic energy to electric heater, then this energy goes to your test metal body.. It increases total mass-energy of metal piece.. Then spreads inside of this body.. and is emitted as bunch of new photons from its surface (because there is no other way to decrease temperature, no air gas molecules in vacuum).

I was asking about method of heating of body in vacuum.. How do you want to increase temperature of metal (or any body) inside of vacuum.. ? It can be done by photons (light) (like this happens with Sun -> Earth).. or direct touch with something much hotter.. or beam of accelerated electrons.. or.. propose something else?

"Increasing temperature in vacuum" is interesting subject by itself.. The only way body, levitating inside of your vacuum, can get, is in the form of photons arriving from environment around your body... Highly accelerated electrons hitting your body to give their kinetic energy (and this way increasing temperature).. would give completely unreliable results, because of their enormous mass-energy.. (mass of electron = 1/1836.15 mass of proton).. You couldn't be sure that electrons fly away from test body or remained f.e. on surface..

Modern instrument for measuring weight is mass spectrometer. Which measures mass of quantum particles and/or their quantity and/or their charge.. https://en.wikipedia.org/wiki/Mass_spectrometry

If you have hot (spherical) body which has some temperature T, it's emitting photons in the all directions uniformly. It's called inverse-square law. Once photon escapes body, energy (and thus mass) of that body, must decrease. The hotter body is, the more energetic photons are emitted. It's called black body radiation. Therefor it's possible to make IR thermometers working from distance. They observe (absorb) photons and analyze where is their peak and maximum. To check if they work correctly, use traditional Mercury thermometer and IR thermometer and compare their results. This process can be reversed. f.e. beam of electrons hitting body, after collision they will give body part, or all, of its kinetic energy, and mass-energy of body will be increased. Energy will spread across entire body, and temperature of body will increase, and it'll be again emitted in form of photons.

The one of the most common way of breaking in somebody computer/smartphone is by intercepting DNS somebody is using, which can be done by f.e. breaking in to Wifi Router and replacing DHCP settings in it by fake made DNS daemons. They will be monitoring and logging what user is doing, which websites user is visiting (when web browser is asking DNS for IP of given name).. and then replacing them by fake-HTTP servers in fake-DNS records. If you are walking with your smartphone and using any free WiFi Hot Spot you will find in the city to save regular LTE transfer there is no, and never will be, encryption that can help you.. Even if you don't do that, somebody can break in your home WiFi router. And then your computer/smartphone will download modified versions of apps which auto-update..