X-rays detected from the dark side of Venus

Posted: October 17, 2016 by oldbrew in Astronomy, Celestial Mechanics
Tags: ,
2012 Venus transit [credit:  JAXA/NASA/Lockheed Martin

2012 Venus transit [credit: JAXA/NASA/Lockheed Martin]

Venus is certainly an oddball in various ways. Is that the ghost of Velikovsky lurking in the background to this story?

Venus and Mercury have been observed transiting the Sun many times over the past few centuries. When these planets are seen passing between the Sun and the Earth, opportunities exist for some great viewing, not to mention serious research.

And whereas Mercury makes transits with greater frequency (three times since 2000), a transit of Venus is something of a rare treat. In June of 2012, Venus made its most recent transit – an event which will not happen again until 2117.

Luckily, during this latest event, scientists made some very interesting observations which revealed X-ray and ultraviolet emissions coming from the dark side of Venus.

This finding could tell us much about Venus’ magnetic environment, and also help in the study of exoplanets as well. For the sake of their study (titled “X-raying the Dark Side of Venus”) the team of scientists – led by Masoud Afshari of the University of Palermo and the National Institute of Astrophysics (INAF) – examined data obtained by the x-ray telescope aboard the Hinode (Solar-B) mission, which had been used to observe the Sun and Venus during the 2012 transit.

In a previous study, scientists from the University of Palermo used this data to get truly accurate estimates of Venus’ diameter in the X-ray band. What they observed was that in the visible, UV, and soft X-ray bands, Venus’ optical radius (taking into account its atmosphere) was 80 km larger than its solid body radius. But when observing it in the extreme ultraviolet (EUV) and soft X-ray band, the radius increased by another 70 km.

To determine the cause of this, Afshari and his team combined updated information from Hinode’s x-ray telescope with data obtained by the Atmospheric Imaging Assembly on the Solar Dynamics Observatory (SDO). From this, they concluded that the EUV and X-ray emissions were not the result of a fault within the telescope, and were in fact coming from the dark side of Venus itself.

They also compared the data to observations made by the Chandra X-ray Observatory of Venus in 2001 and again in 2006-7m which showed similar emissions coming from the sunlit side of Venus. In all cases, it seemed clear that Venus had unexplained source of non-visible light coming from its atmosphere, a phenomena which could not be chocked up to scattering caused by the instruments themselves.

Comparing all these observations, the team came up with an interesting conclusion. As they state in their study:
“The effect we are observing could be due to scattering or re-emission occurring in the shadow or wake of Venus. One possibility is due to the very long magnetotail of Venus, ablated by the solar wind and known to reach Earth’s orbit… The emission we observe would be the reemitted radiation integrated along the magnetotail.”

In other words, they postulate that the radiation observed emanating from Venus could be due to solar radiation interacting with Venus’ magnetic field and being scattered along its tail. This would explain why from various studies, the radiation appeared to be coming from Venus’ itself, thus extending and adding optical thickness to its atmosphere.

If true, this finding would not only help us to learn more about Venus’ magnetic environment and assist our exploration of the planet, it would also improve our understanding of exoplanets.

Full report: X-rays detected from the dark side of Venus | Phys.org

Talkshop note – copied from Wikipedia:
On January 29, 2013, ESA scientists reported that the ionosphere of the planet Venus streams outwards in a manner similar to “the ion tail seen streaming from a comet under similar conditions.”

When a planet behaves like a comet: The tail of Venus and the weak solar wind | Phys.org

  1. Curious George says:

    Why did they wait for a Venus transiting the Sun? Then you have to separate the dark side of Venus from a very bright Sun. When Venus is far from the Sun, we still see half of the dark side. To wait for a transit looks like asking for trouble.

  2. oldbrew says:

    The full study is here: http://dx.doi.org/10.3847/0004-6256/152/4/107

    We studied the Venus transit across the solar disk, which occurred in 2012 and was observed with Hinode/XRT in the X-ray band and SDO/AIA in the EUV and UV bands. We have measured a significant X-ray residual flux from Venus’ dark side (i.e., from the Earth-facing side) during the transit that was significantly above the estimated noise level of 2 DN s−1, as reported by Kobelski et al. (2014).

  3. Alan Poirier says:

    Venus is certainly an odd planet. A captured comet?

  4. tallbloke says:

    Venus is the same size as Earth. Not a ‘captured comet’.

  5. tom0mason says:

    To paraphrase Douglas Adams —

    “We’ll be saying a big hello to all intelligent lifeforms everywhere and to everyone else out there, the secret is to rip the particles apart, guys.”

  6. hunter says:

    I bet it has something to do with voltage potentials from liquid minerals and metals flowing on and near the surface of Venus.

  7. pg sharrow says:

    Venus is not a former comet. Em….. I agree however, Venus could not have originated in it’s present orbit. Wrong rotation direction and speed and far too much atmosphere to have existed in it’s present orbit for over 4 billion years. Present magnetic fields and volcanic activities indicate much younger conditions. Rotation direction and speed indicates being a former gas giant satellite. The orbit plain of Venus indicates it’s origin is of this solar system and is not an interloper.
    There are several indications of close encounters with something LARGE in our solar system over the time since it’s origin…pg

  8. Alan Poirier says:

    If anyone follows the Thunderbolt crew, they contend Venus was a satellite of Saturn (along with Earth and Mars) that was captured by the Sun.

  9. Oldbrew, TB interesting discussion here a few years ago https://tallbloke.wordpress.com/2013/04/04/tom-van-flandern-was-the-planet-mercury-once-a-moon-of-venus/. From that I bought Van Flandern’s book

  10. oldbrew says:

    Certainly the amount of volcanic activity on Venus is extremely high compared to the other rocky planets, and no obvious explanation exists – unlike Jupiter’s moon Io for example, which is known to be strongly stirred up by Jupiter itself.

    ‘Spacecraft that have flown by Io since 1979 have observed numerous surface changes as a result of Io’s volcanic activity’

  11. oldbrew says:

    Old but still worth a look…

    Surprise! Venus May Have Auroras Without a Magnetic Field
    By Charles Q. Choi, Space.com Contributor | April 5, 2012

    “The plasma dynamics of Venus and Earth are surprisingly similar, despite their very different magnetic environments, with and without intrinsic magnetic fields,” said study lead author Tielong Zhang.

    It’s often said that Earth’s magnetosphere ‘protects’ the atmosphere against the force of the solar wind, but Venus with almost no magnetosphere still manages to have by far the thickest atmosphere in the inner solar system.

  12. pg sharrow says:

    While Venus and Earth are in nearby orbits and are similar in size, they are nothing alike. They display different conditions due to history of their creation, rotation speed and direction, magnetic fields, atmospheric and surface conditions. Mars is similar to earth but smaller.
    It is interesting that Aurora is caused by Solar wind and magnetic fields rather then planetary magnetic fields. I have watched the curtains and streamers in the land of the midnite sun. The earths magnetic fields do have an effect on the Aurora Display. One could say that Venus is a good proxy for a non rotating, magnet field less Earth. Oh yes, and without a LARGE moon. Not much in common, really,..pg

  13. pg sharrow says:

    @oldbrew, I understand that Venus slight backwards rotation is “rapidly” slowing, as if it were being “stirred” in the correct direction by wind and maybe even subsurface forces. Rotating bodies tending to align their axis and spin do to their angular momentum induced fields…pg

  14. oldbrew says:

    NASA: Why doesn’t Venus have a magnetic field ?

    ‘Today, the only magnetic field Venus may have comes from the interaction between Venus’s upper atmosphere and the solar wind. The interaction causes electric currents to flow in the upper atmosphere which then create a weak magnetic field that streams behind the planet like a comet’s tail.’