I am just curious if solar panels, because they absorb radiation, cool the atmosphere.  If there were enough of them, would the temperature be different?  I'm not a physicist or student.
86839
I guess that energy will be used up and, at the end, will contribute to heat the earth, so I see no big differences...  please explain your point of view.
49127
Sun is generating energy by nuclear fusion. And nuclear fusion will emit energy in the form of gamma rays.  Normally earth's ozone filtering the Ultraviolet radiation. And magnetic fields of earth deflecting the cosmic rays(charged particles).  But what kind of natural system protecting us from sun's gamma ray as it is main product of nuclear fusion?     Note: As we know gamma ray can be blocked by denser materials like   several meters of thick lead (Pb).
22968
This is homework. I've tried my best to find the best answer that I could understand and could be accepted by my lecturer.   I've searched my lecture notes, wiki and google to find some good explanation defining solar irradiance. But somehow I still don't understand how I should 'define solar irradiance'. Can someone give me a few good sentences explaining solar irradiance. What are the changes, if any, in a photovoltaic cell (in terms of short-circuit current and open-circuit voltage) if the irradiance is reduced by 50%?
123770
I'm looking for a list of nearly all elements and the temperatures they can reach when in a state of plasma. It is for a project I am working on. However, there isn't a list on google.  Preferably one that is hot enough to survive a drop from orbit.
16200
The resources that I've checked out seem to say thermal radiation only occurs in the infrared and visible spectrum. For example my heat transfer textbook and the Wikipedia page on .  In my mind thermal radiation is just energy emitted as a result of internal collisions from temperature. So, since temperature can range from 0K to huge numbers, I would think you would have a similar range of emitted energies. So then thermal radiation could occur throughout the whole of the electromagnetic spectrum.
84772
This well-observed phenomenon has, besides several others, always been a fascination to me. We are well aware of several theories, experiments, and practical applications of this well-known phenomenon, but is it established what goes on at the grassroots of reflection?  My high school teacher once told me that whenever light is incident on any reflecting surface, its electrons absorb the energy of the photon and release back the same energy. If this is actually true, then I have plenty of questions to continue, but if it is not, then what is reflection, and how and why does it take place?
47641
I'm just starting to learn physics and I have a question (that is probably stupid.)  I learned that energy levels that the bound electron can have are discrete. I also learned that when an electron transitions from one level to another, a photon with a specific wavelength (energy) is created and released into the wild.  My question is this: are there holes in the electromagnetic spectrum, values of frequency that the created photon can't possibly have?
111547
I have made a solar panel charger, it consists of a 1.2 watt panel connected to a buck converter, then to the phone.  Now, when I connect it, it charges the phone and in the battery settings it shows it is charging as "plugged ac" and slow charging.  I wanted to test if it can slow down the discharge rate, so I came up with a test procedure where I:   Downloaded "battery drainer" app (which essentially turns on cpu stress, gps, vibrator, full brightness etc);   Measure the time it take for the phone to get to 90% from 100% with solar panel attached and without solar panel attached.   But the time it takes to discharge is almost the same. I am wondering what am I missing. Wouldn't the solar charging increase the discharge time?  When I measured the solar panel output it was 5 V and around 110 mA.   Thank you, any help will be appreciated.
24667
I don't really know much about entropy but I learned recently that the entropy in the universe is constantly increasing and that perhaps someday we will reach maximum entropy and the universe will end in heat death. In order for this to be true there are two prerequisites:   Heat must constantly be created. There must be no way to destroy heat (at least no way that turns it into a more useful form of energy).   1 is certainly true. Every process creates some heat. When a person walks his/her feet hit the ground with kinetic energy and the friction creates heat.   But I don't see how 2 can be true. For one thing, heat never even leaves its place of origin (earth, another planet or a star). In order for heat to travel in requires air (or some other conductor/convector). Since there is no air in space there is also no heat. Heat leaves things only in the form of electromagnetic radiation (light) (in the case of earth, infrared).   So conversion from heat to light is certainly possible and is even found in nature. Now how do we get from light to other forms of energy? Well, photosynthesis. Solar panels. So this is possible too. If so, why will we ever run out of useful energy? Even if the rest of the universe does, can't we still reharness our own energy by converting the heat to light and light to other forms of energy?  Suppose the sun died (and leave aside the fact that it would first destroy earth with a supernova), can't we just put up a huge solar panel around earth to pick up all the infrared and convert it back to useful energy?
9912
Considering how low the power density is at the sun's core, I seem not to be able to expect what would happen to matter in case it was thrown inside the sun's core. For example, let's assume an Earth-like planet is placed at the center of the Sun's core, and with the power density of 276.5 $watts$/$m^3$ which is very low to even raise the temperature of the Earth by any noticeable degree. That was one thought. The other thought was that, the temperature in the core is already 15 million degrees K, so any matter there should get close to this temperature quickly enough.  So now I'm very confused,  like will the planet stay there intact for thousands or even millions of years until it has accumulated enough energy to melt or vaporize ?  Or there are other types of energy absorption the planet would experience and thus have a shorter time staying as one piece in the core ?  Just for trying to get a practical and numerical answer to this question, let it be : how long can the Earth as a whole survive in the core of the sun ?
48483
Okay, so everywhere I've read, I hear the main difference is the requirement of a medium. But for example, if you take the case of heat 'radiating' from  a red-hot iron, isn't that actually  and not ? I mean, isn't the temperature difference between the surrounding air and the iron causing the air to gain heat?
118330
We usually say that the ultimate source of energy for earth is the Sun. So this means that sun creates energy but according to the law of the conservation of energy energy can neither be created nor destroyed, so how does the energy come into the sun? That is just an example. We know that energy is transformed from one form to another but is not created and destroyed. But that is confusing because there must be an ultimate source of energy. How is  energy created in this source? If it is related to the atomic level, then how can atoms possess energy? Is the law of the conservation of energy untrue?
102265
The electromagnet spectrum looks to be continuous, yet energy is discrete. Shouldn't one see evidence of the electron's "quantum leap"? What's going on?     Moderator, please size my photo. Thank you.
106650
I have found that light always produces heat. The only cases I think heat is absent with light is  and  (maybe because they emit low energy but maybe the heat is still present?). So my question is: Is heat energy always present when light is emitted, specially for bright light(more energy)?    If some example or any links can be provided, then it will be very helpful.
28356
A show on  the weather channel said that as a water molecule ascends in the atmosphere it cools. Does it make sense to talk about the temperature of a single molecule?
1173
How does the surface of the photosphere conduct thermal energy from the convective zone to the corona, while remaining at such a relatively low temperature itself?  It seems odd to me that the photosphere is wedged between the convective zone and the corona, both of which are millions of degrees in temperature, while the photosphere itself is observed to be much colder by comparison - approx. 5-10 thousand degrees.  Based on my understanding of convection, this would require thermal energy to jump from the convective zone directly to the corona, and somehow skip the photosphere surface material in-between.  Is there a different model of convection that explains this? Or is there a type of matter with thermal conductive properties that could accomplish this?  EDIT: Perhaps the convective zone is emitting heat as a different form of energy, such as electromagnetic - thereby allowing the outer layers to cool and sink in standard convection, but without directly heating up the surface of the photosphere.  Based on my understanding of the standard model of the sun, the following layers should be present:  Predicted:   The core A central area with pressures high enough to induce hot fusion of atomic nuclei The radiative zone A spinning ball of somewhat solid material surrounding the core, through which energy is conducted via radiation   Semi-observable:   The convective zone A layer of plasma surrounding the radiative zone, through which energy is conducted thermally via convection flows - millions of degrees in temperature This is the subject of some 2012 studies by NASA in coordination with various other reputable institutions, which observed that the sun's convection appears to be "anomalously weak"    Observable:   The surface of the photosphere The border between the convective zone and the corona - temperature in the ballpark of 5-10 thousand degrees The corona The outer plasma atmosphere, where flares take place - millions of degrees in temperature
11483
I was looking at  on why  and emission lines don't cancel out:      An experiment shining light on the material and looking at the   reflected spectrum will see absorption lines at those frequencies,   because the relaxation of the excited electrons will emit back   radiation all around randomly, whereas the reflected spectrum is at a   specific angle.   However it is not totally convincing to me. The photons that get emitted towards the center of the Sun (by the electrons in higher energy states that absorbed a photon earlier) would get absorbed again when they hit a different electron (and then re-emitted) and would eventually make it out. So why don't absorption and emission lines cancel out in our Sun?