Photo Credit: Damia Bouic, DARTS, ISAS, JAXA
By Amber Bennett
You'd think that the rotational speed of a planet would remain constant. Take earth for instance. At the equator, the planet spins at roughly 1,600 km/hr (1,000 mph), and that speed doesn't change much, which gives us our consistent 24-hour days.
However, scientists have discovered that Venus doesn't have a constant rotational speed. In fact, it can speed by up to 2 minutes per Venus day. The reason? The extremely thick atmosphere that surrounds the planet, which moves faster than the planet spins.
With the help of computer models, researchers found that the winds on Venus move an astonishingly 100 m/s (about 224 mph)! That's about a third of the speed of sound on earth.
Measurements of Venus' day length, or rotational period, can vary by up to 7 minutes, likely because of how the atmosphere moves against the mountains.
It's important to note that the rotational speed isn't constantly increasing, however. Another force is at play to slow it back down, likely gravitational influence from the sun.
Given enough time, ignoring this small difference would lead to a noticeable difference in things like when the sun rises and sets. Well ... noticeable might not be the right word; I don't think many of us would have noticed the sun rising 27 seconds earlier today than it did on this day in 1972. It would be a measurable difference, though.
However, scientists have discovered that Venus doesn't have a constant rotational speed. In fact, it can speed by up to 2 minutes per Venus day. The reason? The extremely thick atmosphere that surrounds the planet, which moves faster than the planet spins.
With the help of computer models, researchers found that the winds on Venus move an astonishingly 100 m/s (about 224 mph)! That's about a third of the speed of sound on earth.
Measurements of Venus' day length, or rotational period, can vary by up to 7 minutes, likely because of how the atmosphere moves against the mountains.
It's important to note that the rotational speed isn't constantly increasing, however. Another force is at play to slow it back down, likely gravitational influence from the sun.
More on Earth's Rotation
Actually, Earth's rotation IS slowing very gradually due to tidal forces from the moon, so that the length of a day gets a tiny bit longer over time. Presently, a day lasts about 24 hours and 0.68 thousandths of a second. To account for the fact that a day is slightly longer than 24 hours, leap seconds are periodically added to all of our clocks. We have added 27 leap seconds since 1972 when the first leap second was added.Given enough time, ignoring this small difference would lead to a noticeable difference in things like when the sun rises and sets. Well ... noticeable might not be the right word; I don't think many of us would have noticed the sun rising 27 seconds earlier today than it did on this day in 1972. It would be a measurable difference, though.
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