<p>As others have calculated, there are no predicted double transits. Since Venus transits for about 12 hours each hundred years (roughly), Venus is in transit for about 1/100000 of the time. </p>

<p>Thus there is a (roughly) 1 in 100000 chance that a randomly chosen transit of mercury will coincide with a transit of Venus. Since Transits of Mercury occur every 10 years or so, one would expect a double transit to happen on average once every million years. This is clearly a very rough estimate, but we should not be surprised that such an event has not happened in the historical period.</p>

CC BY-SA 3.0
2016-01-18T01:08:16.273Z
I like this answer, as it illustrates the reason very nicely.
Jens
CC BY-SA 3.0
2016-01-16T15:14:52.490Z
2016-01-16T15:14:52.490Z
James K
<p>Transits of Mercury happen fairly frequently due to its short period, but transits of Venus are less frequent.  I've looked over the data available to me and found that there have been transits of both planets in the same calendar-year in 1631 (Nov &amp; Dec) and in 1769 (Jun &amp; Nov).  </p>

<p>What would really be interesting is if the two planets transited the Sun at the same time! With the rule being, that the second transit begins before the first transit completes.  </p>

<p>Can we figure out if they have ever so transited, or if they ever will so transit?</p>

<orbit><venus><mercury><planetary-transits>
Are there ever any simultaneous transits of both Mercury and Venus as seen from the Earth?
Cyberherbalist
# Are there ever any simultaneous transits of both Mercury and Venus as seen from the Earth?

(Asked by: username_0 on 2016-01-15)

Transits of Mercury happen fairly frequently due to its short period, but transits of Venus are less frequent. I've looked over the data available to me and found that there have been transits of both planets in the same calendar-year in 1631 (Nov & Dec) and in 1769 (Jun & Nov).

What would really be interesting is if the two planets transited the Sun at the same time! With the rule being, that the second transit begins before the first transit completes.

Can we figure out if they have ever so transited, or if they ever will so transit?

**Tags:** orbit, venus, mercury, planetary-transits


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## 1 answers

### Answer by username_1 on 2016-01-16. Score: 11

As others have calculated, there are no predicted double transits. Since Venus transits for about 12 hours each hundred years (roughly), Venus is in transit for about 1/100000 of the time.

Thus there is a (roughly) 1 in 100000 chance that a randomly chosen transit of mercury will coincide with a transit of Venus. Since Transits of Mercury occur every 10 years or so, one would expect a double transit to happen on average once every million years. This is clearly a very rough estimate, but we should not be surprised that such an event has not happened in the historical period.

> **Comments:**
> **username_2**: I like this answer, as it illustrates the reason very nicely.  

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