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August 09, 2019, 10:30 UTC

Planet Venus will be visible on images coming from space for few days

Venus on image from LASCO, SOHO Planet Venus is visible on images coming from the solar coronagraph LASCO. This image was received on 09.08.2019.


Not very rare, but very spectacular astronomical phenomenon - planet Venus appears on the images coming from space, the event can be observed for about almost a week and a half. Venus is currently passing at the maximum distance from Earth on the opposite side of the Sun, and strange though it may seem, but because of this exact position it is now most visible and bright.

This is due to the fact that Venus, like any other planet, shines only because it reflects the sunlight. That is easy to understand knowing the fact that when the planet is closest to Earth, it is when its orbit is between the Earth and the Sun, the sun illuminates it from behind. For this reason, the planet will not be visible to us. And the opposite, when Venus is located on the opposite side of the Sun it is reflecting the light from its illuminated side facing the Earth, it is then when the planet is most visible and bright. The closest analogy to this is the phases of the Moon all familiar to everyone from observation. The moment when the Moon passes right between the Earth and the Sun, we witness a new moon (dark moon), because the Sun shines from the opposite side. To mention that the solar eclipses occur only during the new moons it doesnt happen when the Moon is located somewhere between the Sun and the Earth but when it is passing directly across the solar disk, fully or partly obscuring it. The moment when the Moon is located on the opposite side of the Sun, we witness a full moon, from this position the Sun fully illuminates the lunar side facing the Earth. That is why only during the full moon lunar eclipses can be observed. It occurs when the Moon is directly behind Earth and covered in its shadow.

Using these terms, we can say that now we are observing the Venusian full moon, more correctly, the Venus is in its maximum full phase.

The more known and rare effect associated with the convergence of the inner planets (Mercury and Venus) with the Sun is their transit across the solar disk. It may seem that this event shouldnt be so rare and should occur with every revolution and transit the solar disk accordingly. It would have been so if the orbits of the planets looked as they are drawn in school books - concentric circles or ellipses located on one plane. In reality, each orbit is slightly tilted towards a common plane (ecliptic). For this reason, both planets Venus and Mercury while approaching the Sun, passing above or below the solar disk. Their direct hit of the solar disk is an exceptional event. The transit of Venus, as a rule, happens only twice in a century, and both of these events have already taken place in 21st century, in 2004 and 2012, the next one we will have to wait till the year 2117. Mercury in this regard got more luck. The planet's closest transit will happen very soon on 11 November 2019, and the next one after the 13 years later, in 2032.

Despite the fact that Venus now looks very bright on images coming from space, it is extremely difficult to see it from Earth at the moment. It is due to its close proximity to Sun: Venus is now drowning in the solar rays scattered in the earth's atmosphere. The amateurs of the starry sky will have to wait at least until the end of September when Venus leaves the Suns aura and the evening star will shine in the sky again. On the solar images, the planet will be visible for about a week and a half till the 20th or 24th of August.


Laboratory of X-ray astronomy of the Sun, Lebedev Institute, Russia
© XRAS tesis.lebedev.ru