Refining this value would become one of the main scientific reasons for transit observations. By the pair of June transits in and , scientists had determined that observations of the transit from multiple locations on Earth could be used to gauge solar parallax and from that the length of an AU.
Using combined data from both these transits, Jerome Lalande, a French astronomer, computed the AU to be 95 million miles million kilometers. Data from expeditions to view the December transits of and further refined the value. Simon Newcomb of the US Naval Observatory combined data from the four transits to calculate the value of Petersburg with a two-lens refractor and a weak solar filter, he discovered the Venusian atmosphere, a continuing motive for transit observations.
With the AU precisely determined, and the vast technological improvements available for the June and Venus transits, astronomers realized that these events could help them investigate exoplanets.
The transit fostered more ideas on how to use transits to discover exoplanets; transit studies have since become the most prolific exoplanet-detection method. Transits of Venus happen twice every or The last two of these occurred in and Transits are very important for another reason — They help us identify other planetary systems!
There are six primary strategies astronomers use to find planets orbiting other stars. These include astrometric, radial velocity, spectroscopic, direct imaging, microlensing, and transit detection methods. By far, transit detections have been responsible for discovering most of the extrasolar planets we know about today.
Once the size of the AU was known, it was possible to determine the real size of the solar system and, using a technique called stellar parallax, which I will talk about in a later post, the distances to the stars. You may remember from your high school science lessons that there is a relationship between the three quantities: the speed a smaller object such as the Earth orbits a larger object such as the Sun , its distance from the larger object and the mass of the larger object.
Once the distance from the Earth to Sun and the speed of the Earth in its orbit around the Sun were known, it was then possible to work out the mass of the Sun. This turned out to be around , times the mass of the Earth. The Russian astronomer Mikhail Lomonosov observed the transit and reported a bump or bulge of light off the solar disc as Venus began to exit the Sun.
He correctly attributed this bulge to the bending of sunlight by an atmosphere around Venus. This was the first time that an atmosphere had been found around any planet other than the Earth. The transit of Venus was observed by millions of people throughout the world, although not everyone in the world could see it. Even though the distance from the Earth to the Sun is now well known, so the transit was of lesser scientific important than earlier transits, it would still have been an interesting sight to observe.
It was also possible to view the Sun through the special glasses which are sold to view solar eclipses. Children Observing the transit in East Timor — image from Wikimedia commons.
To view it, please click on the link below. My blog explainingscience. It is written in a style that it is easily understandable to the non scientist. Publications and videos For links to my books and videos please visit www. Like Like. When this occurs it is known as a transit of Venus. More details of transits of Venus are in my previous post: Transit of Venus.
I enjoyed reading thoroughly. Like Liked by 1 person. I wonder, did you see the picture of the Mercury transit in the Sunday Times magazine? The photography exhibition of Solar System pictures opening at the Natural History Museum later this month sounds interesting. Transits of Mercury are much more frequent that Transits of Venus, but because Mercury is further from Earth and smaller the black dot on the surface of the Sun caused by a transit of Mercury is much smaller an thus harder to see than the black dot caused by a transit of Venus.
Very interesting. I had no idea of the role these observations had played in the development of modern astronomy. Thank you for comment and sorry you missed the transit. The transit was on a grey, overcast, rainy day around me, which of course it would be. Reblogged this on A Transit Diary, of Sorts. Have a look and I hope you enjoy as I did. Reblogged this on The Somnium Project. You are commenting using your WordPress. You are commenting using your Google account.
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