Return of the Pioneer Anomaly

One of the many pieces of evidence put forward for the existence of Planet X over the last few decades is the so-called ‘Pioneer anomaly’.  The two Pioneer spacecraft were sent on an incredible voyage across the solar system, visiting a number of planets as they went.  They not only imaged these planets, but used the gravity of the planets to accelerate onwards, deeper into the solar system.  This gravity assist is often used to allow spacecrafts to pick up speed.  As the Pioneer probes travelled across the outer planetary zone and on towards the Heliopause beyond in the 1990s, it became apparent that the craft were not moving away from the solar system quite as quickly as the theoretical trajectory projections demanded.  Something was essentially slowing them down.  Additionally, similar effects were noted for the Galileo and Ulysses probes.

Many ideas were put forward, including either gravitational or physical interaction with clouds of interplanetary dust in the Kuiper Belt, or even the added gravitational tug of an undiscovered Planet X body.  One of the lead researchers into the Pioneer anomaly at the Jet Propulsion Laboratory  was John Anderson (1), who, interestingly, also had a longstanding interest in the possible existence of a Planet X body (2).  At one point, puzzled physicists began to wonder whether this marginal but definitive anomaly might require new laws of physics (3).  In the end, it was agreed by technical experts that the anomalous deceleration was a result of radiation pressure caused by non-uniform heat loss from the probes (4,5). Flights of fancy about missing planets and new physics were promptly put to bed.

Despite this, the anomaly seems to persist in the increasingly accurate navigation and telemetry data returning from various spacecraft performing flybys past the Earth (6).  Similarly, the Juno spacecraft, now orbiting fairly closely around Jupiter, is reported to be slightly misplaced from its expected position (7).  This has been determined by looking at the Doppler shift of ranging data from the probe as it circumnavigated the poles of the great gas giant.  Quixotically, Juno did not exhibit the same anomalous behaviour during a previous flyby of Earth.  This suggests that this is not, then, the result of an internal machination of the probe itself, as described for the Pioneer probes.  Instead, there does appear to be an unexplained external effect worth exploring:

Another mystery is that while in some cases the anomaly was clear, in others it was on the threshold of detectability or simply absent – as was the case with Juno‘s flyby of Earth in October of 2013. The absence of any convincing explanation has led to a number of explanations, ranging from the influence or dark matter and tidal effects to extensions of General Relativity and the existence of new physics. However, none of these have produced a substantive explanation that could account for flyby anomalies.” (8)  Read More…

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Jupiter’s Internal Powerhouse and Ultracool Dwarfs

Jupiter, the solar system’s largest planet, is turning out to be as majestic as its ancient name implies.  High definition images taken of its poles, transmitted back to Earth by the space probe Juno, show a vibrant, churning cloudscape which appear to have been artistically generated in oils (1).  The gnarly appearance of the storms and tempests which are woven into this mind-blowingly immense vista seem peaceful enough from space, but the ferocity of their winds can only be imagined.  Although the colours have been enhanced to a certain extent artificially (2), Juno’s imaging equipment has captured the incredibly beautiful blue colours of the polar zones and the immense set of storms swirling within.

(Image credit: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt/Seán Doran)

These dramatic regions contrast strongly with the generally dull series of beige bands wrapping around the more familiar equatorial region (although Juno has also allowed us to better appreciate the intricate patterns of these banded zones, too) .  These blues are more reminiscent of the ice giants Neptune and Uranus, and perhaps even of Earth – although the constituent gases of the atmospheres of these worlds can differ significantly from Jupiter’s.  which give the clouds.  The different colours and properties of Jupiter’s clouds can be attributed to their constituent gases – mostly hydrogen and helium, but also water, ammonia, methane and sulphur.

It seems to me that the solar system is starting to come to life – not in the way of biological life, although that may yet come to be, but instead in terms of our appreciation of its rich complexity and visuality.  The Pioneer and Voyager space probes provided what were incredible images of the outer solar system planets back in their day.  But limitations in the image-capturing technology also created a sense in those images of dull uniformity.

In the decades before the space-probe images had been sent back from the outer solar system, sci-fi writers, film-makers and scientists had created an amazing array of ideas about what these worlds might be like.  This potential had become ingrained within the public collective consciousness, and to some extent helped drive NASA’s ambitious space programme forward.  This was enhanced by a sense of mystery – and a hope of alien life.  However, the images returning to our television screens in the latter part of the 20th century clearly did not do these worlds justice.  So, although obtaining the planetary images were astonishing achievements in themselves, the disappointing lack of features within them dashed many hopes, and provided the public with a new view of the outer solar system.  Like lifeless Mars and overheated Venus, the outer solar system consisted of a rather mundane set of giant planets distinctly lacking in the vibrant complexity of our own Earth.  Read More…

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