1 Joule of meteorite energy will give approximately 1 Joule of heat in an impact.I need a way to convert kinetic energy into thermal energy
80% nitrogen, 20% oxygen are a good approximation.as well as the specific heat of the entire Earth's atmosphere
No. And your approach to calculate it does not work.The idea is to see if the heat generated by many meteoroid fragments could possibly account for any climate change.
Solar constantMain article: Solar constant
The solar constant, a measure of flux density, is the amount of incoming solar electromagnetic radiation per unit area that would be incident on a plane perpendicular to the rays, at a distance of one astronomical unit (AU) (roughly the mean distance from the Sun to the Earth). The "solar constant" includes all types of solar radiation, not just the visible light. Its average value was thought to be approximately 1.366 kW/m²,[7] varying slightly with solar activity, but recent recalibrations of the relevant satellite observations indicate a value closer to 1.361 kW/m² is more realistic.[8]
Total (TSI) and spectral solar irradiance (SSI) upon EarthTotal
Solar Irradiance upon Earth (TSI) was earlier measured by satellite to be roughly 1.366 kilowatts per square meter (kW/m²),[7][9][10] but most recently NASA cites TSI as "1361 W/m² as compared to ~1366 W/m² from earlier observations [Kopp et al., 2005]", based on regular readings from NASA's Solar Radiation and Climate Experiment(SORCE)
mfb said:Apart from the redundancy, where is the problem in the quoted part?
Uncertainties at the numbers would be nice, but if you really need these values for actual scientific work, take the references given there.
mfb said:1 Joule of meteorite energy will give approximately 1 Joule of heat in an impact.80% nitrogen, 20% oxygen are a good approximation.
However, your approach cannot work. The atmosphere is not an isolated system, it constantly exchanges energy with space and with the surface of the earth. Think about day and night: The temperature differences show you how much energy is exchanged every day. This is several orders of magnitude larger than any long-term climate changes.
It is better to consider the equilibrium temperature*: The atmosphere will reach this very quickly and follow it, if it changes.
Meteorite impacts do not change the equilibrium temperature, as soon as their produced dust is gone (only relevant for really large impacts).
*averaged over natural cycles like days and years. If you want to do it right, this can get quite tricky, but it is possible.Short answer:
No. And your approach to calculate it does not work.
mfb said:But then we need an increased impact rate to change the temperature.
Anyway, the incoming energy is extremely small compared to the radiation from the sun.
I found an upper estimate of 10000 tons per day, with ~40km/s this gives a total energy of 8*10^15J. This is the energy the Earth gets from the sun within 50 milliseconds. The solar radiation adds 2 million times more energy than meteors, even with this high number of incoming material.
forumasker said:First, let's just try and see how much energy the Earth's atmosphere would gain. THEN, let's consider how much energy the Earth loses and gains over time.
Do you have a link to that I could look at?
Did you notice that these are two different measurements? It is explained in the quoted part.256bits said:Did you not notice the 1.366 kW/m² vs 1361 W/m² that's sloppy on the author's part not uncertainty.
Wikipedia with reference to abc.net.auWikipedia said:Around 15,000 metric tons of meteoroids, space dust, and debris of different types enters Earth's atmosphere each year
mfb said:Did you notice that these are two different measurements? It is explained in the quoted part.
QUOTE]
The wiki author has used kilowatts/ m^2 versus watts/m^2 - it is the units that I am referring to - in his TSI.
And 1366W/m^2 = 1.336kW/m^2, as dots are used as decimal mark.256bits said:mfb said:Did you notice that these are two different measurements? It is explained in the quoted part.
The wiki author has used kilowatts/ m^2 versus watts/m^2 - it is the units that I am referring to - in his TSI.
sophiecentaur said:The Whole Earth gets the energy and the mean temperature increase will depend upon the total thermal capacity, eventually.
sophiecentaur said:I meant that thermal capacity affects the rate of temperature change.
When an object or substance is in motion, it possesses kinetic energy. When this motion is impeded by a force, such as friction, the kinetic energy is converted into thermal energy. This is because the force causes the molecules within the object to vibrate or move faster, generating heat.
The temperature of the object will increase as the kinetic energy is converted into thermal energy. This is due to the increased motion and vibration of molecules, which results in a higher average kinetic energy per molecule.
Yes, all forms of kinetic energy can be converted into thermal energy as long as there is an opposing force present to impede the motion and create friction. This includes mechanical, electrical, and thermal energy.
In most cases, yes, thermal energy is produced when kinetic energy is converted. However, if the motion is impeded by a force that does not generate heat, such as magnetic or elastic forces, then thermal energy may not be produced.
Some common examples include rubbing your hands together to warm them up, braking while riding a bike, or rubbing two sticks together to create fire. Any situation where motion is impeded and results in the production of heat is an example of converting kinetic energy into thermal energy.