I think you are confused about what both "heat" is and maybe light/EM radiation. The definition of heat is simply "thermal energy transfer". And EM radiation transfers thermal energy (or at least heats up the recipient). Thus, any electromagnetic radiation can be considered heat.LightningInAJar said:
IR (and other EM radiation) is energy transfer not in the form of work or mass transfer...Orodruin said:
Not always. It can be part of a thermodynamic system such as a photon gas. It can be heat but must not be so.russ_watters said:
It sounds like you are saying that if you draw a system boundary such that the energy transfer is internal it doesn't count.Orodruin said:
Just like internal forces don’t count in a free body diagram.russ_watters said:
Ok...but that just means that if you draw a different system boundary/diagram, maybe they do. So in my opinion this line of reasoning creates an unnecessary distinction-without-a-difference.Orodruin said:
Are you arguing that the distinction between internal and external forces is unnecessary?russ_watters said:
No, I'm arguing that the distinction of whether EM is "heat" depending on the system boundary is unnecessarily narrow and leads to contradiction (the same EM being "heat" and "not heat" at the same time). Also, that isn't what you said to begin with. You said "IR is not heat" when I think it should have been "IR is not always heat".Orodruin said:
It doesn't. That's why IR telescopes are usually cooled to a temperature well below whatever objects they will be observing and why the Spitzer telescope had to stop long wavelength observations once it ran out of liquid helium coolant. The noise from the telescope's internal IR swamped these long wavelength observations with too much noise to get useful images.snorkack said:
That’s just word wrangling and ”IR is not heat” is technically just saying that there is not a equivalence.russ_watters said:
You are missing the point. The same thing can be said about internal vs external forces.russ_watters said:
Fair enough. I'm generally a fan of concise wording, but I submit that if I misunderstood your intent the OP may have as well. So thanks for clarifying.Orodruin said:
Hubble doesn't need extreme cooling of its sensors like JWST does. Hubble also has a smaller mirror, reducing its resolution and light gathering compared to JWST, and observes targets in a different part of the EM spectrum. Hubble is designed to image from UV down through visible light to the near-IR, the part of the IR band that's closest to visible light.LightningInAJar said:
LightningInAJar said:
Images of the Earth with much higher resolution than what JWST could deliver are not hard to find.LightningInAJar said:
Infrared radiation is a type of electromagnetic radiation that has a longer wavelength than visible light. It is not visible to the human eye, but can be felt as heat.
Infrared radiation is detected using special sensors, such as infrared cameras or thermal imaging devices. These sensors can detect the heat emitted by objects in the form of infrared radiation.
No, not all infrared radiation gets detected as heat. Infrared radiation can also be absorbed by certain materials or reflected by others, depending on their properties. For example, some materials, like glass, are transparent to infrared radiation and do not absorb it as heat.
Infrared radiation is generally not harmful to humans, as it is a natural form of energy that our bodies can handle. However, prolonged exposure to high levels of infrared radiation can cause burns or damage to the skin.
Infrared radiation has many applications in science and technology. It is commonly used in thermal imaging to detect heat signatures, in remote sensing to study Earth's atmosphere and surface, and in medical imaging to diagnose diseases. It is also used in communication systems, such as remote controls and wireless data transfer.