Posts Tagged ‘planetary’

Juno probe


There’s nothing like observation for contradicting, or supporting, theory and the Juno probe has already upset a few ideas that scientists had about Jupiter.

Since it established orbit around Jupiter in July of 2016, the Juno mission has been sending back vital information about the gas giant’s atmosphere, magnetic field and weather patterns, as Universe Today reports.

With every passing orbit – known as perijoves, which take place every 53 days – the probe has revealed more interesting things about Jupiter, which scientists will rely on to learn more about its formation and evolution.

During its latest pass, the probe managed to provide the most detailed look to date of the planet’s interior. In so doing, it learned that Jupiter’s powerful magnetic field is askew, with different patterns in its northern and southern hemispheres.

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Lunar precession update

Posted: October 15, 2017 by oldbrew in Fibonacci, Maths, moon, Phi, solar system dynamics
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Credit: NASA


I found out there’s an easy way to simplify one of the lunar charts published on the Talkshop in 2015 on this post:
Why Phi? – some Moon-Earth interactions


In the chart, synodic months (SM) and apsidal cycles (LAC) are multiples of 104:
79664 / 104 = 766
728/104 = 7

The other numbers are not multiples of 104, but if 7 is added to each we get this:
86105 + 7 = 86112 = 828 * 104 (TM)
85377 + 7 = 85384 = 821 * 104 (AM)
5713 + 7 = 5720 = 55 * 104 (FMC)
6441 + 7 = 6448 = 62 * 104 (TY)

TM = tropical months
AM = anomalistic months
SM = synodic months
LAC = lunar apsidal cycles
FMC = full moon cycles
TY = tropical years


Here’s an imaginary alternative chart based on these multiples of
104. [Cross-check: 828 – 766 = 62]

In reality, 55 FMC = just over 62 TY and 7 LAC = just short of 62 TY.
For every 7 apsidal cycles (LAC), there are 766 synodic months (both chart versions).

In the real chart:
For every 104 apsidal cycles, all numbers except SM slip by -1 from being multiples of 104. So after 7*104 LAC all the other totals except SM are ‘reduced’ by 7 each.

In the case of tropical years, 6448 – 7 = 6441 = 19 * 339
19 tropical years = 1 Metonic cycle

If the period had been 6448 TY it would not have been a whole number of Metonic cycles.
Also 6441 * 4 TY (25764) is exactly one year more than 25763 synodic years i.e. the precession cycle, by definition.

Fibonacci: 104 is 13*8, and the modified FMC number is 55 (all Fibonacci numbers).

Phi: we’ve explained elsewhere that the number of full moon cycles in one lunar apsidal cycle is very close to 3*Phi².
We can see from the modified chart that the FMC:LAC ratio of 55:7 is 3 times greater than 55:21 (55/21 = ~Phi²)
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Note – for more discussion of the ~62 year period, try this search:
site:tallbloke.wordpress.com 62 year
[see Google site search box in grey zone on left of this web page]

Juno Jupiter Mystery

Posted: September 30, 2017 by oldbrew in solar system dynamics
Tags: ,

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‘Scientists are puzzled’ as usual when actual evidence arrives, but that’s only to be expected. Not looking good for metallic hydrogen theory?

Acksblog

The Current State of JUNO

The lead scientist, Dr. Scott Bolton, admits essentially that Jupiter is not a gas giant, stating ” We’re seeing a lot of our ideas were incorrect and maybe naive.” (1)  Scientists are puzzled to see that the familiar striped cloud layers ‘may be’ only skin deep. These zones and belts either don’t exist or the Juno microwave instrument just isn’t sensitive to it. (2) The gravity experiment is not seeing a concentrated core at the center of the planet or a pure hydrogen interior, the two competing hypotheses, Dr. Bolton stated “and what we found was that neither are true.” Instead, the data suggests a ‘fuzzy’ core, with unexplained ‘anomalous masses’. (3) The enormously powerful ultraoviolet auroral ovals are imagined to be due to energetic particles descending around the poles, but what the Juno JEDI energetic particle detector has detected to date are streams of…

View original post 669 more words

Credit: NASA


This is from a Q&A on a website linked with Sydney Observatory. We add brief notes at the end.

Lionel asks: Congratulations on your Venus book.

Excellent. I notice that there is a 243 year cycle for Transits of Venus
243 x 365.242 = 224.7 x 395
So far so good. The axial rotation period for Venus is 243.1 days.
Is this a coincidence or is there some underlying geometrical fact that I cannot see?
well-done,

Answer: An interesting and complex question that I address below.

Patterns in the transits of Venus
Let us first look at the patterns in the transits of Venus. We need to note that Venus and the Earth line up with the Sun every 583.92 days or 1.59872 years. This is called the synodic period.

If there was a transit, say the one in June 2004, for another transit to occur, the two planets must not only line up with each other and the Sun, but do so after an integer number of years so that they are back in the right places on each of their orbits.

Venus and Earth fulfil these requirements after five synodic periods = 7.9936 years as this is almost, though not quite, equal to the integer eight. Thus transits of Venus generally occur in pairs eight years apart. However, because of the slight inequality there is no third transit after another eight years.

A more accurate relationship occurs after 152 synodic periods = 243.00544 years or ~395 Venus years. The pattern of Venus transits thus repeats at 243 year intervals (This is the cycle quoted by Lionel in his question above). For example, the first pair of June transits after 8 June 2004 begins on 11 June 2247. Of course, in the meantime there is also a pair of December transits beginning in 2117.

The rotation of Venus
Scientists using radar observations from the 1960s onwards discovered that Venus spins backwards, that is in the opposite direction to its motion around the Sun, at the slow rate of 243.02 days.

They soon realised that means that Venus, almost but not quite, shows the same face towards the Earth each time the planets are lined up with each other and the Sun. Somehow there is a resonance between the motion of the Earth around the Sun and Venus’ spin around its axis. Scientists are unsure why this is the case, but one suggestion is that Venus is more massive on the face turned towards the Earth at those times and consequently it was gravitationally captured by the Earth.

How is it worked out that Venus shows the same face towards the Earth each time they line up? The quoted value of 243.02 days is with respect to distant stars. With a little arithmetic (taking inverses) we can easily convert that value to the rotation period with respect to the Sun or, in other words, to the day on Venus. It is 116.75 (Earth) days. Five of those periods equal 583.75 days, which is almost the same as the 583.92 day synodic period. So each time the planets line up Venus shows almost the same face to the Sun and hence the same face to the Earth, which is always on those occasions on the opposite side of Venus.

Coincidence or not
As Lionel points out it is interesting that transits of Venus repeat in a cycle of 243 years while the rotation period of Venus with respect to the stars is 243 days, The above detailed discussion indicates that there is no obvious connection that gives rise to the same number in each case. However, the calculations all depend on many of the same factors such as the orbital periods of Venus and the Earth so maybe there was a chance that the same number should recur.

Note the values quoted above are from the NASA Venus Fact Sheet.

Source: Are transits and the rotation of Venus linked? – Observations
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Talkshop notes

Re: ‘Five of those periods equal 583.75 days, which is almost the same as the 583.92 day synodic period.’ [‘Venus and the Earth line up with the Sun every 583.92 days or 1.59872 years’]

Note 1: 23 solar rotations @ 25.38 days = 583.74 days
This also looks like a resonance, this time between the Sun and the Venus day.
. . .
Re: Venus and Earth fulfil these requirements after five synodic periods = 7.9936 years
A more accurate relationship occurs after 152 synodic periods = 243.00544 years or ~395 Venus years.

Note 2: using their own data, 157 synodic periods is more accurate, i.e. closer to a whole number of Earth orbits.
1.59872 * 152 = 243.00534 years (as stated in their notes)
1.59872 * 157 = 250.99904 years (~408 Venus years)
Of course that would be an ‘extra’ five synodic periods = 7.9936 years.

That may contradict the official ‘wisdom’ but there it is. It was discussed in some detail in this 2015 Talkshop post (some readers may find the comments to be of interest):
Why Phi? – a Venus transit cycle model

Mercury [image credit: NASA]


The first photos of ice at Mercury’s poles were released in 2014 but this research goes a step further, as Phys.org reports. It finds that ‘the total area of the three sheets [is] about 3,400 square kilometers—slightly larger than the state of Rhode Island’.

The scorching hot surface of Mercury seems like an unlikely place to find ice, but research over the past three decades has suggested that water is frozen on the first rock from the sun, hidden away on crater floors that are permanently shadowed from the sun’s blistering rays.

Now, a new study led by Brown University researchers suggests that there could be much more ice on Mercury’s surface than previously thought.

The study, published in Geophysical Research Letters, adds three new members to the list of craters near Mercury’s north pole that appear to harbor large surface ice deposits.

(more…)

Image credit: NASA


We now know that Saturn’s rings share a process with spiral galaxies, and the unique co-orbital pattern of two of its moons get some attention.

This view from NASA’s Cassini spacecraft shows a wave structure in Saturn’s rings known as the Janus 2:1 spiral density wave, reports Phys.org.

Resulting from the same process that creates spiral galaxies, spiral density waves in Saturn’s rings are much more tightly wound.

In this case, every second wave crest is actually the same spiral arm which has encircled the entire planet multiple times. This is the only major density wave visible in Saturn’s B ring.

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Cassini probe at Saturn
[credit: NASA]


NASA’s Cassini space probe is still sending back useful data before it ends its 20 year mission by diving into the unexplored Saturnian atmosphere.

The spectacular rings of Saturn may be relatively young, perhaps just 100 million years or so old, says BBC News.

This is the early interpretation of data gathered by the Cassini spacecraft on its final orbits of the giant world. If confirmed, it means we are looking at Saturn at a very special time in the age of the Solar System.

Cassini is scheduled to make only two more close-in passes before driving itself to destruction in Saturn’s atmosphere on 15 September. The probe is being disposed of in this way because it will soon run out of fuel.

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Credit: NASA


Among other findings, solar EUV [extreme ultraviolet radiation] turns out to be a greater planetary force than expected in this new research. Also the bow shock is greater the nearer Mars gets to the Sun during its orbit.

As the energetic particles of the solar wind speed across interplanetary space, their motion is modified by objects in their path. A study, based on data from ESA’s Mars Express orbiter, has thrown new light on a surprising interaction between the planet Mars and supersonic particles in the solar wind, reports Phys.org.

Scientists have long been aware that a feature known as a bow shock
forms upstream of a planet – rather like the bow of a ship, where the water is slowed and then diverted around the obstacle.

The bow shock marks a fairly sharp boundary where the solar wind slows suddenly as it begins to plough into a planet’s magnetosphere or outer atmosphere.

In the case of Mars, which does not generate a global magnetic field and has a thin atmosphere, the main obstacle to the solar wind is the ionosphere – a region of electrically charged particles in its upper atmosphere.

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Jupiter is living up to its billing as a ‘planet on steroids’.
http://www.theguardian.com/science/2016/jun/04/probe-jupiter-juno

Planet Pailly

Last week, the Juno mission flew over Jupiter’s Great Red Spot and sent back some spectacular close-ups. But I’m not ready to talk about that. Not yet. I’m still catching up on the Juno news from two months ago.

Toward the end of May, NASA released a ton of fresh data from Juno, including new information about Jupiter’s auroras. Astro-scientists had previously known about two sources contributing to these auroras: the solar wind and the Io plasma torus. Now Juno may have discovered a third.

As Juno flew over Jupiter’s poles, it detected electrically charged particles flying up.

I can’t emphasize enough how weird this is. I wanted to write about it right away, but I held off doing this post because I was sure I must have misunderstood what I was reading.

Auroras are caused by electrically charged particles accelerated down toward a planet’s magnetic poles. These…

View original post 132 more words


Much media attention on this new paper this week. Is there a surprise lurking in the details now that the orbit period of the seventh planet has been confirmed?.

What the numbers in the diagram show is the orbits per planet in a fixed period (top row), the conjunctions per planet pair in the same period (second row), and the ratios that represents (third row).

The number of conjunctions of any two planets is the difference between the two orbit numbers in a given period, which in this case is equivalent to just under 1446 Earth days (see data below).

Apart from the obvious symmetry of the ratios, something else arose from the science paper.

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Credit: NASA/JPL


After 20 years of service its time is up, but due to its plutonium power source Cassini can’t be left to find its own final destination. Before its September demise it will weave through Saturn’s rings making yet more observations.

Cassini has used a gravitational slingshot around Saturn’s moon Titan to put it on a path towards destruction, reports BBC News.

Saturday’s flyby swept the probe into an orbit that takes it in between the planet’s rings and its atmosphere.

This gap-run gives the satellite the chance finally to work out the length of a day on Saturn, and to determine the age of its stunning rings. But the manoeuvre means also that it cannot escape a fiery plunge into Saturn’s clouds in September.
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Quote: ‘Flying through Steve, the temperature 300 km above Earth’s surface jumped by 3000°C’.

Thanks to social media and the power of citizen scientists chasing the northern lights, a new feature was discovered recently, as ESA reports.

Nobody knew what this strange ribbon of purple light was, so … it was called Steve. ESA’s Swarm magnetic field mission has now also met Steve and is helping to understand the nature of this new-found feature.

Speaking at the recent Swarm science meeting in Canada, Eric Donovan from the University of Calgary explained how this new finding couldn’t have happened 20 years ago when he started to study the aurora.

While the shimmering, eerie, light display of auroras might be beautiful and captivating, they are also a visual reminder that Earth is connected electrically to the Sun.
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The 1,100 year orbit of ‘DeeDee’

The solar system’s dwarf-planet population is about to increase by one, reports Space.com. The far-flung object 2014 UZ224 — informally known as DeeDee, for “Distant Dwarf” — is about 395 miles wide (635 kilometers), new observations reveal.

That means the frigid object probably harbors enough mass to be shaped into a sphere by its own gravity, entitling it to “dwarf planet” status, researchers said.

Astronomers first spotted DeeDee in 2014 using the optical Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile (though they didn’t announce the discovery until 2016).
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The satellites won’t land as the surface pressure – 92 times that of Earth – and heat of Venus would destroy them. Instead they will look for a ‘mysterious substance’ thought to be lurking in its atmosphere.

NASA has spent $3.6 million to build 12 small satellites to explore the planet Venus in search of a mysterious substance that absorbs half the planet’s light, reports The Daily Caller.

The CubeSat UV Experiment (CUVE) mission will launch the satellites to investigate atmospheric processes on Venus. The 12 satellites vary in size. One is less than four inches across and weighs a few ounces. Another weighs 400 pounds.
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Size comparison of GJ 1132 b (aka Gliese 1132 b) with Earth [credit: Wikipedia]


Early indications from models suggest that ‘an atmosphere rich in water and methane would explain the observations very well.’

Astronomers have detected an atmosphere around the super-Earth GJ 1132b, reports the Max Planck Institute for Astronomy.

This marks the first detection of an atmosphere around a low-mass Super-Earth, in terms of radius and mass the most Earth-like planet around which an atmosphere has yet been detected.

Thus, this is a significant step on the path towards the detection of life on an exoplanet. The team, which includes researchers from the Max Planck Institute for Astronomy, used the 2.2 m ESO/MPG telescope in Chile to take images of the planet’s host star GJ 1132, and measuring the slight decrease in brightness as the planet and its atmosphere absorbed some of the starlight while passing directly in front of their host star.

While it’s not the detection of life on another planet, it’s an important step in the right direction: the detection of an atmosphere around the super-Earth GJ 1132b marks the first time an atmosphere has been detected around a planet with a mass and radius close to that of Earth (1.6 Earth masses, and 1.4 Earth radii).
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View from Titan [artist’s impression]


‘The grains that cover Saturn’s [largest] moon act like clingy packing peanuts.’ An obvious question might be: where is Titan’s electrical charge coming from?

Experiments led by researchers at the Georgia Institute of Technology suggest the particles that cover the surface of Saturn’s largest moon, Titan, are “electrically charged.”

When the wind blows hard enough (approximately 15 mph), Titan’s non-silicate granules get kicked up and start to hop in a motion referred to as saltation. As they collide, they become frictionally charged, like a balloon rubbing against your hair, and clump together in a way not observed for sand dune grains on Earth — they become resistant to further motion.

They maintain that charge for days or months at a time and attach to other hydrocarbon substances, much like packing peanuts used in shipping boxes here on Earth. The findings have just been published in the journal Nature Geoscience.

“If you grabbed piles of grains and built a sand castle on Titan, it would perhaps stay together for weeks due to their electrostatic properties,” said Josef Dufek, the Georgia Tech professor who co-led the study. “Any spacecraft that lands in regions of granular material on Titan is going to have a tough time staying clean. Think of putting a cat in a box of packing peanuts.”

The electrification findings may help explain an odd phenomenon. Prevailing winds on Titan blow from east to west across the moon’s surface, but sandy dunes nearly 300 feet tall seem to form in the opposite direction.
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Credit: IB Times


It’s not yet known what the origin of asteroid (or comet) ‘Bee-Zed’ is or if it’s one of a class of similar objects in retrograde co-orbital resonance, as Phys.org reports. The researchers say ‘how it got there remains a mystery.’

For at least a million years, an asteroid orbiting the “wrong” way around the sun has been playing a cosmic game of chicken with giant Jupiter and with about 6,000 other asteroids sharing the giant planet’s space, says a report published in the latest issue of Nature.

The asteroid, nicknamed Bee-Zed, is the only one in this solar system that’s known both to have an opposite, retrograde orbit around the sun while at the same time sharing a planet’s orbital space, says researcher and co-author Paul Wiegert of Western’s Department of Physics and Astronomy.
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The largest ‘TNOs’

This is about the ‘no-name’ dwarf planet 2007 OR10, which has the unusual property of being 3 times further from the Sun at aphelion (furthest) than at perihelion (nearest).

Everybody gets a moon! With the discovery of a small moon orbiting the third-largest dwarf planet, all the large objects that orbit beyond Neptune now have satellites, reports New Scientist.

Trans-Neptunian objects (TNOs) spend most or all of their orbits beyond Neptune. Last April, the dwarf planet Makemake became the ninth of the ten TNOs with diameters near or above 1,000 kilometres known to have a moon.

So when dwarf planet 2007 OR10 was found to be rotating more slowly than expected, it was suspected that a moon might be the culprit.
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Image credit: NASA

Image credit: NASA


From the research paper: ‘We suggest the possibility that the Earth’s atmosphere of billions of years ago may be preserved on the present-day lunar surface.’

A team of researchers affiliated with several institutions in Japan, examining data from that country’s moon-orbiting Kaguya spacecraft, has found evidence of oxygen from Earth’s atmosphere making its way to the surface of the moon for a few days every month, reports Phys.org.

In their paper published in the journal Nature Astronomy, the researchers describe what data from the spacecraft revealed.
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Saturn and the lunar year

Posted: January 28, 2017 by oldbrew in Maths, solar system dynamics
Tags:

Comparison of Saturn and Earth [image credit: NASA]

Comparison of Saturn and Earth [image credit: NASA]


In a recent post: Sidorenkov and the lunar or tidal year we were looking at the match between tropical years and periods of 13 lunar months (i.e. the lunar, or tidal, year):
353 tropical years = 363 tidal years (where 1 lunar year = 13 lunar tropical months)

Here we want to see if Saturn links to the lunar year.
From the JPL ephemeris [target body: Saturn] we have:
Saturn orbit period = 10755.698 days

Jupiter-Saturn-Earth orbits  chart

Jupiter-Saturn-Earth orbits chart


From another post we produced a chart [right] based on 85 Saturn orbit periods:
85 x 10755.698 days = 914234.33 days

One tidal year = 13 x 27.321582 days = 355.18056 days
914234.33 / 355.18056 = 2573.9987 tidal years (2574)
So 85 Saturn orbits = 2574 tidal years

Since 2574 is divisible by 6 (= 429) we can use the chart to say:
403 Saturn-Earth conjunctions (S-E) = 429 tidal years
or, dividing by 13:
31 S-E = 33 tidal years
therefore, multiplying by 11:
341 S-E = 353 tropical years = 363 tidal years (the original match, see above)
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