What is the difference between sunlight and incandescent light

As photons are bosons, you can put them into the same state and if you did this - you'd get a laser. The photons here have the same wavelength and polarisation but would have a slight spread of energies. We can take this idea further and consider a bose-einstein condensate of photons, only then would all the photons be doing the same thing. So, to summarise, when you have lots of photons, you can make assumptions where the light come from because of the spectrum, but if you were given one photon which could plausibly be produced from the sun or the blub, it would be impossible to tell if it came from a filament or the sun.

Here are already several good answers, but one thing hasn't been addressed, which might be what your friend refers to. The Sun and an incandescent bulb both emit close-to Planck spectra as shown in Tomi's and Cort Ammon's answers.

In contrast, fluoerescent bulbs, or tubes, emit spectra that have multiple spectral lines. Depending on which gas is used in the tube, or what material the tube is coated with, various spectra can be achieved. The color perceived by humans depend on the ratio between the intensity at three wavelength intervals in the blue, green, and red range, respectively.

This is because we only have three different color-sensitive photoreceptor cells, called "cones" in contrast, dogs only have two types of cones and thus lack one "color dimension", while butterflies have five, and mantis shrimps have 16! This means that different spectra can be percieved by humans as the same color. An example of a typical fluorescent lamp is shown below. On top of the spectrum, I've drawn the three spectral ranges that humans are sensitive to. The lamp spectrum is seen to have some larger peaks in the blue, green, and red range, and humans would interpret this roughly as "white".

But the same color could be made — "artificially" as your friend might call it — with some other lines, e. Or, with a Planck spectrum of roughly K. Spectrum of a typical fluorescent lamp black , and sensitivity curves of the three different human cones blue , green , and red.

The difference is expressed in terms of the temperature of the emitting surface. The sun is effectively at about degrees K, while a normal incandescent will run about K, and a halogen about K. On the one hand, in principle it's "simple" to produce a lamp with light essentially equivalent to sunlight - just run it at K. Problem is, no known substance will take that heat without melting. On the other hand, there are a large number of M class stars with a surface temperature of about K not ours, of course - ours is a G class.

Tourists to a planet in orbit around an M class would not need sunblock, for the same reason you don't need sunblock under incandescent lighting,. So, no, incandescent lighting is not unnatural or artificial in the sense your friend thinks.

The same cannot be said for most white LED bulbs, which have a spike in the blue portion of the spectrum, and this does not occur in nature. Either light from a bulb, or light from the Sun, will illuminate my path well enough that I can avoid stepping on the cat.

In that sense, they're the same. The light from the Sun has a color blip, right where early atomic physics suggested the element with two protons in its nucleus would radiate. That element, called Helium from Helios, Greek word for the Sun really does exist. There isn't any of it nor evidence of it in light from a typical light bulb. So, in that sense, light from the Sun and from a light bulb are NOT the same. Your friend sounds like an interesting person to have an argument with but I suspect that the lovely graphs from the other replies are not really going to help you.

One comment was about UV tanning lamps. This is the way to go with your friend, bring other examples into the discussion so you can illuminate! You should then be able to find out where her fuzzy or fixed boundaries are and tweak the discussion accordingly.

If you look at it photon-by-photon, you could not tell the difference between sunlight and laserlight or candlelight. An analogy: if you only looked at one molecule in ice, you could never be sure it was not steam. It is only the statistical distribution of the speeds of the molecules that makes a difference between ice and steam. And either one can burn you.

Similarly, there is a vast and very practical difference between the statistical distribution of the photons in sunlight and the photons from candlelight. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Is the light from the Sun the same as the light from a bulb? Ask Question. The filament in an incandescent lamp is what heats up.

Filaments are made out of double coils of tungsten, a type of metal. Tungsten has a high electrical resistance, causing it to glow incandesce when an electric current flows through.

Electric current, through high electrical resistance, results in heat due to the friction between the material and the electrons that are flowing through the material. Tungsten is used for incandescent bulb filaments because it is extremely resistant to melting at high temperatures. It also does not burn, because gas is injected into incandescent bulbs to eliminate all oxygen. The incandescent lamp was invented by Thomas Edison in At that time, filaments were carbonized fibers made by smothering a certain type of bamboo grown in Kyoto, Japan, but these days a variety of materials and methods are introduced to produce light bulbs.

There are many types of light bulbs, each with their own purpose. For example, there are silica bulbs with silica particles coated electrostatically on their inner surface to vastly improve light transmission and diffusion, krypton bulbs injected with krypton gas higher atomic weight than the normally used argon gas to increase brightness, and reflector lamps using highly reflective aluminum on their inner surface. Fluorescent light, a common form of illumination in offices, has a more complicated light emission mechanism than incandescent light.

Ultraviolet rays created within fluorescent lamps are transformed into visible light that we can see. Electrical discharge phenomena and the "excited state" and "ground state" of electrons play an important role here.

Let's start with a look at the basic structure of a fluorescent lamp. Fluorescent lamps are slender glass tubes coated with fluorescent material on their inner surfaces. Mercury vapor is injected inside, and electrodes are attached at both ends. When voltage is applied, an electric current flows in the electrodes, causing the filaments on either end to be heated up and start emitting electrons. Next, a small gas discharge lamp inside the fluorescent lamp turns off; electrons are emitted from the electrode and they begin to flow toward the positive electrode.

It is these electrons that produce ultraviolet light. Let's take a closer look at the mechanism by which fluorescent light emits ultraviolet rays. Electrons emitted from the electrode collide with the mercury atoms comprising the vapor inside the glass tube.

This causes the mercury atoms to enter an excited state, in which the electrons on the outermost orbit of the atoms and molecules obtain energy, causing them to jump to a higher orbit. Excited mercury atoms constantly try to return to their former low energy state ground state , because they are so unstable. When this happens, the energy difference between two orbital levels is released as light in the form of ultraviolet waves.

However, since ultraviolet rays are not visible to the human eyes, the inside of the glass tube is coated with a fluorescent material that converts ultraviolet rays to visible light. Natural light cycles from bright with a high blue content during the day, to soft with a high red content in the the evenings. The blue-rich bright light of a sunny day highlights primary colors and makes whites look crisp, while the soft light of sunset accents earth-tones and makes skin glow.

Natural light provides the visual aesthetic and biological health and wellness queues we need to see and feel our best! Most artificial light sources emit a static spectrum which means their mix of colors cannot change with time of day.

As a result artificial light sources are designed to either replicate daylight or evening light. Cool white LEDs and most fluorescents are designed to mimic daylight blue-rich light. Blue rich light interferes with our sleep and recovery and should therefore be avoided at night. Traditional incandescent and most Halogen light sources provide good full-spectrum light but can only mimic sunset red-rich light.