It is also closer to the Earth than any other planets. Besides the Sun and the Moon, Venus is the brightest object in the sky. Transit of Venus is a rare astronomical phenomenon. The next transit will occur on 6 June After which it will only recur in When Earth is closer to the Sun's powerful gravity, it moves slightly faster in its orbit than when it's farther from the Sun.
In the future, transits of Venus will become even more rare. This diagram shows the track Venus will take across the Sun in In and , Venus's path will miss the Sun from Earth's perspective. Both Venus's and Earth's orbits precess, meaning they rotate over long time periods to produce a rosette-like pattern.
In other words, Earth's perihelion shifts in its orbit, and so does Venus's. Because of precession, Earth-bound astronomers will only be able to enjoy one ascending-node transit for centuries after the year They will see a descending-node transit in , but 8 years later, in , Venus will come to inferior conjunction too far above the Sun to transit its disk. And over tens of thousands of years, the year cycle will eventually change as the eccentricity of Venus's and Earth's orbits evolve due to the gravitational perturbations of other planets.
Over even longer timescales, chaotic effects take over, and the mathematics becomes so uncertain that today's astronomers can no longer predict when these rare celestial alignments will take place, and what future cycles will be like.
By plotting the number of days into each year when a transit of Venus occurs, it's easy to see the long-term behavior of transits of Venus, and the fact that we're fortunate to live during a period when we get to see two transits at both the ascending and descending nodes. Note the change from the Julian Calendar to the Gregorian Calendar around the year Thanks for the great article.
Learning more about the subtleties of our galaxy is very cool. Since this is a once well twice in a lifetime event, I'm going to make sure to witness it and I can add more fun to the event by visualizing the details in this article regarding the respective orbital planes, speed and orbital nuances of Earth and Venus.
Thanks again! Log in to Reply. I would like to find out about what time of day on June 5th and 6th Venus will start its transit across the sun. I have read a few different articles about Venus's transit and it seems that none of them indicated what time it starts for different areas of the Earth. Tried to print the story as it is very useful however the is a page missing between 5 and 6! The alignment of Sun, Venus and Earth that produces a transit recurs with high precision about 1 arc minute in the relative position of Venus every years.
This recurrence is more precise than the 8-year cycle that usually gives us two consecutive transits. The 8-year cycle is off by nearly 20 arc minutes in position compared to the In Because our Gregorian calendar system is adjusted for the precession of the Equinoxes, the calendar date of the alignment is typically a couple days later each time June 5, vs. The so-called transit of Venus is a much-anticipated event that has attracted wide interest around the globe.
To prepare for the historic spectacle, here are some frequently asked questions and answers on the rare celestial sight:. When Venus crosses in front of the sun, astronomers refer to this as a "transit. Due to the tilt of the planet's orbit, transits of Venus are some of the rarest astronomical sights because they only occur in pairs eight years apart, once every years or so. The last Venus transit occurred on June 8, , and the next one will not be visible again until the year , more than years from now.
As Venus passes in front of the sun, the planet will cover only a small fraction of the solar disk, which means observers need to protect their eyes. It is very dangerous for humans to stare at the sun even mid-transit without proper eclipse glasses or solar filters for binoculars and telescopes. To observe the sun, dense filters are used to block damaging rays.
The only safe filters are 14 welder's glass, which is sold in specialized welder's supply stores. Special eclipse glasses are also available from telescope stores and astronomy clubs they should only cost a couple of dollars.
Another way to watch the transit is using a "pinhole camera," which can be made from a large cardboard box.
0コメント