|Why is the temperature of the atmosphere 1700
|Question Date: 2019-02-22|
The temperature of Earth’s atmosphere depends
on which layer you’re in. Earth’s atmosphere
is divided into five main layers: the
troposphere, the stratosphere, the mesosphere, the
thermosphere, and the exosphere (space).
If you measure temperature as you go up, the
temperature kind of zig zags. The air starts off
warm in the troposphere but gets colder as you go
up, then warms again in the stratosphere.
The mesosphere is the coldest layer, at -90
degrees Celsius; this is where meteors burn
up. The thermosphere is probably the
layer you’re asking about because it gets really
hot, around 1500-1700 degrees Celsius.
Interestingly, it doesn’t feel warm up there
because it’s so close to being a complete
vacuum. The reason this layer is so hot is
because it absorbs a lot of energy from the
sun, like x-rays and UV radiation, and converts it
into heat. Also, since it’s so low
pressure, the small number of gas particles it
contains heat up very easily and quickly. These
two factors together create the intensely hot
temperature of the outer atmosphere.
The temperature of the entire atmosphere is not
1700°C, only the layer (
one of five which comprise
the atmosphere) called the thermosphere.
This is the officially the second-highest layer,
but the layer beyond it (
the exosphere ) is so sparsely populated
that it is essentially empty space (such that some
scientists do not even consider it part of the
For the purposes of this
question, consider the thermosphere to be the
outer layer of the atmosphere. As the outermost
layer, it is the first to be impacted by the
high-energy radiation emitted by the sun. As these
photons collide with particles in the thermosphere
and transfer energy to the gases there, in some
ionizing them and causing the auroras.
Transferring energy to the gas particles is
another way of saying that the temperature of the
gas particles is increased. This is because
temperature is essentially a measure of the
kinetic energy of molecules in a material. The
temperature of the thermosphere is so high for a
combination of reasons. First, it absorbs a lot of
much of the ultraviolet, visible, and gamma
radiation emitted by the sun is absorbed in
this portion of the atmosphere).
In addition, there aren't many particles there
(even though it
is denser than the exosphere, the pressure in the
thermosphere is only a small fraction of that in
troposphere where humans live). This has the
twofold effect of each particle taking in a lot of
energy, and limiting the possibility of collisions
with other particles to get rid of energy.
Interestingly, despite the temperature of the
thermosphere being so high, it would feel quite
cold and a typical thermometer would read below
freezing. This is also a result of the low
pressure: few particles means there would not
be enough collisions to transfer a significant
amount of energy (i.e., to cause a significant
increase in temperature of the thermometer). Even
though the temperature of the individual particles
is very high, the total amount of heat contained
is relatively low because of the low density.
(This information is in the above references. For
more, see the ScienceLine answers
You did not specify which planet, moon, or star
has an atmosphere with a temperature of 1700
degrees Celsius, so I can't answer as each
atmosphere has its own reasons for having the
temperature that it does.
If you are referring to Earth's atmosphere,
thenthe answer is that Earth's atmosphere is
not that hot. Earth's atmosphere ranges from
about -50 Celsius to about 50 Celsius depending on
season, time of day, and location. 1700 degrees
Celsius is hot enough to melt most rocks. If
Earth's atmosphere were to become that hot, then
the entire planet would become one gigantic ocean
of molten lava.
The temperature of the atmosphere on Earth is
mostly between 0 degrees Celsius [freezing point
of water = 32 deg F] and 40 degrees Celsius [104
degrees F]. The temperature of the atmosphere
above Earth depends on the altitude [how high
above earth the atmosphere is], and things like
the weather at that altitude.
Wikipedia mentions that “Atmospheric
temperature is a measure of temperature at
different levels of the Earth's atmosphere. It is
governed by many factors, including incoming solar
radiation, humidity and altitude”. You can
read more on the link below:
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