The day after tomorrow morning it will be possible to see (through a telescope or on the Internet) the planet Hema passing across the surface of the sun * a small disc on a large disc
Eran Ofek
Mercury, as photographed by the Mariner 10 spacecraft in 1974. On average, there are about 13 transits of Mercury per century. Photo: NASA
Direct link to this page: https://www.hayadan.org.il/mercury050503.html
On Wednesday morning, Mercury will be visible to an observer from Earth as it passes across the Sun. Mercury is the closest planet to the sun, and it orbits it once every 88 days. Occasionally during its orbit it is visible to the observer from Earth as it passes across the sun's disk. This event does not occur once per orbit of the planet around the sun, and this is because the planet Mercury orbits the sun in a somewhat inclined orbit relative to the orbit of the earth around the sun.
In fact, these events of the passage of a planet across the Sun, called transits, are quite rare. On average there are about 13 transits of the planet Mercury every hundred years. Transits of the planet Venus are even rarer: the last transit of Venus occurred in 1882, and the next transit will occur in 2004. Since Mercury and Venus are the only planets that orbit the Sun in an inner orbit to that of Earth, only they can be seen in transit .
For an observer from Israel, the disc of the planet Hema will be seen touching the sun at 08:12:28 Israel time; After 4 minutes and 26 seconds the entire disc will be on the surface of the sun and moving across it; At 13:27:05 the star Mercury will reach the other end of the sun's disc; And after 4 minutes and 25 seconds it will completely leave the solar disk. Those who will watch the event, through a shielded telescope, will be able to see the disk of the planet moving slowly across the disk of the sun.
Since the angular diameter (the size as seen by an observer from Earth) of Mercury is 150 times smaller than the angular diameter of the Sun, it is impossible to see the transit without binoculars or a small telescope. You should also be equipped with appropriate protective measures against sunlight.
It is absolutely forbidden to look at the sun with the eye, binoculars or a telescope without appropriate protective measures; Directly looking at the sun will cause severe damage to the eyes and even blindness. "Protective measures" such as carbonized glass are not suitable for observing the sun and their use may cause irreversible damage to the eyes. One of the appropriate protective measures is welding glass number 14 or "mylar paper" - paper that filters the sun's radiation and especially its ultraviolet radiation.
Today, events such as transits have negligible astronomical significance, but in the 18th century this phenomenon was used to measure the distance between the Earth and the Sun.
Today we know this distance with great precision (about 150 million km), but in the past it was only roughly estimated. The Greek astronomer Ptolemy estimated the distance between the Earth and the Sun at about 8 million km, while Johannes Kepler estimated it at about -22 million km.
The British astronomer Edmund Halley suggested measuring the distance between the Earth and the Sun using the transit of Venus. The method is based on measuring the start or end time of the transit from two points on Earth. The start/end time of the eclipse is different at every point on Earth, and the time differences depend on the distance of the Sun and Venus from Earth.
In 1769, an expedition led by the British Captain Cook, who discovered New Zealand on that trip, set out to measure the transit of Venus from Tahiti. The historical importance of this expedition is reflected in France's gesture towards the British explorer. At that time, France and Great Britain were at war, but the French government forbade its fleet to attack Captain Cook's ship because it was on an important mission for the benefit of all humanity. Indeed, Captain Cook's mission was crowned with success and thanks to his measurements, the distance between the Earth and the Sun was estimated to be approximately 153 million km.
People who do not have appropriate equipment will be able to watch the transit of the planet Hema in real time via the Internet. Tel Aviv University's Wise Observatory will operate a special camera, which will transmit the images to the Internet at: http://wise-obs.tau.ac.il/astroclub/transit The Weizmann Institute of Science and the Givatayim Observatory will hold an activity (for a fee) in honor of the event
The next transit of a planet will be on June 8, 2004. This event will be easier to observe since the angular diameter of Venus is significantly greater than that of Mercury.
This week: a solar eclipse by the planet Mercury
This is how the observation should be made when the planet Mercury will pass across the sun on Wednesday. The recommended precautions are necessary
On Wednesday morning, the hot star, Mercury, will pass over the sun
and will cause a "solar eclipse" different from the usual one, which he performs
The moon * is a rare event, the observation of which requires great caution
Dr. Noah Brosh
This week, on Wednesday, May 7, from 7:13 am Israel time, a relatively rare celestial phenomenon will begin to show. The planet Mercury will perform a very partial solar eclipse. It will be possible to observe it, in an observation that requires quite a bit of caution - and whoever succeeds, will get to see the eclipse, as a black dot on the bright background of the sun.
Although the phenomenon itself has no scientific value nowadays, when spacecraft periodically visit most of the planets, including Mercury - the event is of educational value in that it focuses attention on one of the main "players" in our solar system, and also highlights the difficulties in discovering planets To others, moving around suns (in other systems).
Of the large members of the solar system, only Mercury and Venus can pass between us and the sun. The reason is: the distance of these planets, from the Sun, is smaller than the distance of the Earth.
Despite this, the transits of the inner planets across the surface of the Sun - as seen from Earth - are relatively rare. In the 21st century, only 14 transits of Mercury will occur, and only two of Venus. The rarity is a result of the relative tilt between the Earth's orbit, and the orbits of the other two planets.
Although the planet is between us and the sun, it is not exactly on the same line of sight, but slightly above or below this line. When the three bodies are arranged exactly on the same line, observers from Earth see a tiny black dot, on the bright disk of the Sun. This is actually a solar eclipse, caused by another planet, and not by our moon, as it happens in conventional solar eclipses.
In a normal solar eclipse (by the moon) the intensity of the light reaching us from the sun decreases, in a very significant way - and it is described by the words "darkness at noon" or "the night falling in the middle
today".
This will not be the case in the upcoming eclipse caused by the planet Mercury. The decrease in the intensity of the sunlight that will reach the country will only be one hundred percent, so tiny that it cannot be measured, except from space and with special equipment. This low intensity of the falling light is a result of the small diameter of the planet Mercury, relative to the diameter of the Sun: only about 5000 km, compared to the diameter of the Sun which is almost 1,400,000 km.
This highlights the difficulty in detecting planets orbiting other suns using the eclipse method. With this method, the presence of the planet is detected when it passes over the other star (its sun) and causes a decrease in light. But in order for this to be measurable, the planet has to be huge!
Anyone who plans to watch this interesting, unique phenomenon must be careful not to look directly at the sun. Viewing the sun with the naked eye is dangerous. may cause serious damage to the eye. The use of observation tools such as binoculars or a telescope, without taking maximum precautions, will cause permanent damage - up to the loss of sight!
Besides the use of special light filters, which are only in the hands of a few, it is therefore recommended to use the method of projecting the image, as explained in the illustration shown here: in this method, a telescope, which magnifies the image 70 times or more, casts the image of the sun on white paper. The planet Mercury will appear as a black dot when passing the surface of the Sun. It will "crawl" from one side of the sun
to her other side.
The duration of the transit of Mercury across the surface of the Sun will be approximately five hours and 20 minutes. So that there will be enough time, until about half an hour after noon today, to observe and experience the event.
For news on this topic at the BBC
Knower of the sun, planet Mercury and Venus
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