Because the gravitational pull of the planet isn't strong enough to hold any gasses.
Mercury
Mars has almost no atmosphere. APEX=MERCURY has no atmosphere.
There aren't. Mercury has almost no atmosphere. Therefore, it cannot have storms.
The planet Mercury has almost no atmosphere, it's essentially a vacuum.
Mercury has only a trace atmopshere of hydrogen that is almost null.
Mercury is pitted with craters because Mercury has almost no atmosphere to protect itself.
Very, very little, as Mercury's atmosphere is almost a vacuum only minute traces of gasses are found.
Of the inner four terrestrial planets in our solar system - Mercury, Venus, Earth and Mars - Mercury has almost no atmosphere.
The atmosphere on Mercury is about 42% oxygen, but is very thin as to be almost non-existent.
Mercury is so close to the Sun and so small that it has only a very small atmosphere. It has been blown away by the Sun's solar winds. That means that there is almost no air on Mercury.
Mercury has almost no atmosphere so that could be the answer. The otherpossible answeris Mars, which certainly does have a (thin)atmosphere.
Mercury is so close to the Sun and so small that it has only a very small atmosphere. It has been blown away by the Sun's solar winds. That means that there is almost no air on Mercury.