Archive for the ‘Astrophysics’ Category

View from the Moon [credit: Wikipedia]

View from the Moon
[credit: Wikipedia]


First there was a report saying:
‘Computer model shows moon’s core surrounded by liquid and it’s caused by Earth’s gravity’

Of course the words ‘Computer model shows’ will ring a few alarm bells with some talkshop readers. Yes, it’s a theory based on a model, and the output of ‘climate models’ has led to many controversies so we may well be suspicious already.

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saturn2

From NASA:

Cassini took readings of the day-length indicator regarded as most reliable, the rhythm of natural radio signals from the planet. The results give 10 hours, 45 minutes, 45 seconds (plus or minus 36 seconds) as the length of time it takes Saturn to complete each rotation. Here’s the puzzle: That is about 6 minutes, or one percent, longer than the radio rotational period measured by the Voyager 1 and Voyager 2 spacecraft, which flew by Saturn in 1980 and 1981.

[Tallbloke notes that Venus has also slowed by an unexplained six minutes since 1997]

Cassini scientists are not questioning Voyager’s careful measurements. And they definitely do not think the whole planet of Saturn is actually rotating that much slower than it did two decades ago. Instead, they are looking for an explanation based on some variability in how the rotation deep inside Saturn drives the radio pulse.

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imageThe New Scientist reports the discovery of many more electron eating bacteria.

Geobacter and Shewanella were the first, now a further eight have been identified.

Kenneth Nealson from the University of South California “electrons must flow in order for energy to be gained. This is why, when someone suffocates another person, they are dead within minutes. You have stopped the supply of oxygen, so the electrons can no longer flow”. Nealsons team have grown electric bacteria on battery electrodes. Bacteria can either “eat” electrons from the higher voltage, or “breathe” electrons to the lower voltage electrode

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From Nature.com, a new paper which looks at how dry atmosphere’s of some exoplanets could cast doubt on long cherished notions about planet formation. Current mainstream thinking is that big planets form a long way out and migrate inwards. Perhaps the opposite may be the case, and ‘hot jupiters’ form near the parent star and increase the size of their orbits asthay gain angular moentum. Supporting this possibility, a recent paper by Poppenhaeger on the electromagnetic coupling of proto-planetary discs with the host star posit a slowing the stellar rotation and a shift of its angular momentum to the forming planets.

hd189733Scientists searching for worlds outside of the Solar System say that three such planets — distant gas giants that resemble Jupiter — are surprisingly dry.

The atmospheres of these exoplanets, known as ‘hot Jupiters’, contain between one-tenth and one-thousandth water vapour than predicted, measurements from the Hubble Space Telescope show. The findings, published 24 July in Astrophysical Journal Letters1, are at odds with theories of how planets form.

Madhusudhan thinks that it is possible, but not likely, that clouds are skewing his results. The particles would have to be high in the atmosphere, above the water vapour, for this to be true. That would place the clouds in the thinnest part of each exoplanet’s atmosphere, but they could be too heavy to stay aloft. The clouds would also need to survive in the wide range of temperatures the three planets’ atmospheres span — 900–2,200 ºC — which models can’t yet explain. “There is just no candidate cloud composition or physics that can do it,” he says.

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ImageReversals of the solar magnetic dipole in the light of observational data and simple dynamo models
V. V. Pipin., D. Moss, D. Sokoloff, and J. T. Hoeksema

Astronomy & Astrophysics, July 17th 2014

http://dx.doi.org/10.1051/0004-6361/201323319

ABSTRACT
Context. Observations show that the photospheric solar magnetic dipole usually does not vanish during the reversal of the solar magnetic field, which occurs in each solar cycle. In contrast, mean-field solar dynamo models predict that the dipole field does become zero. In a recent paper it was suggested that this contradiction could be explained as a large-scale manifestation of small-scale magnetic fluctuations of the surface poloidal field.
Aims. Our aim is to confront this interpretation with the available observational data.

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I came across this paper today while searching for the heat capacity of Venus near surface atmosphere, which is actually an ocean-like (in thermodynamic terms) supercritical fluid. It presages Harry Dale Huffman’s ‘rediscovery’ of the lapse rate calculation by four decades. Another paper, much more recent, (Bolmatov et al 2013) contains some theory which raises yet more questions about the reasons for Venus’ high surface temperature. So, greenhouse due to radiative proerties of co2 as Sagan claimed, lapse rate due to gravity and pressure as Nikolov and Zeller maintain, or the thermal properties of supercritical fluids and geothermal energy having a hard time escaping the lower atmosphere? Let the debate recommence!

venustemp1

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While browsing Ian Wilson’s excellent Astro-Climate Connection blog, I found a graphic showing the coincidence of El Nino with the alignment of the Lunar line of nodes (declination cycle) and line of apse (orbital precession), with the Sun. I’ve taken the liberty of adding my Solar – El Nino hypothesis to it: the proposal is that El Nino tends to be initiated as the cycle starts to decline steeply and initiated again at solar minimum as it ‘bottom’s out’. I’ll reproduce Ian’s accompanying text below the break but to get to the point, here’s  the result:

enso-lunisolar

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From Ian Wilson’s Astro-Climate Connection blog:

rranom.vic.0112.19917

The Moon’s orbit is tilted by approximately five degrees compared to the Earth-Sun plane. The net affect of this is that the strength of Lunar-tides at a given latitude on the Earth’s surface vary in strength over a cycle of 18.6 years. This 18.6 year Draconic cycle is also clearly evident in the small changes that take place in the rate of rotation of the Earth.

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I’m of the opinion that before getting into the complexity of numerical modelling, it’s wise to put considerable effort into trying to understand the physical processes at work in the climate system, and the origins of the energy flows that drive them. David Evans’ recent series of posts over at Jo Nova’s site have generated a lot of interesting discussion (despite being roundly ignored by Anthony Watts at WUWT), and I think we can shed some light on the ‘mysterious 11yr lag’ between solar input and climate response.

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kaptyenchart-600x383

A newly discovered planet pair orbiting a red dwarf a mere 13 light years from our solar system is in a near 2:5 orbital resonance. From National Geographic:

An international team of astronomers reports the discovery of two new planets orbiting Kapteyn’s star, a nearby red dwarf with a long history. One of its newly discovered worlds, dubbed Kapteyn b, circles the star at the right distance to allow seas to survive on its surface, where water is seen as a key ingredient of life as we know it.

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Andromeda galaxy [credit: Wikipedia]

Andromeda galaxy
[credit: Wikipedia]

Once again observation clashes with theory. This time it’s dwarf galaxies putting a spanner in the works of the ‘standard model’, says an international team of researchers.

“When we compared simulations … to what is observed by astronomers, we found a very substantial mismatch,” the lead author said.

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Speculative result based on a new toy at University of Göttingen

How Did the Moon Really Form?

Dan is a deputy news editor for Science.
Email Daniel

By Daniel Clery Thursday, June 5, 2014 – 3:45pm

Planetary scientists have long believed that our moon formed following a collision between Earth and another planet, but studies of Earth and moon rocks suggest otherwise. A new analysis of the composition of moon rocks brought back by Apollo astronauts may help finally resolve the mystery.

Science magazine article

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Big Bang [image credit: wikipedia]

Big Bang [image credit: wikipedia]

More ‘settled science’ on the ropes.

Quote: ‘These results are consistent with what would be expected from ordinary geometry if the Universe was not expanding, and are in contradiction with the drastic dimming of surface brightness predicted by the expanding Universe hypothesis.’

But Wikipedia says : ‘The Big Bang theory is the prevailing cosmological model for the early development of the universe. The key idea is that the universe is expanding.

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Hexagon found on Neptune?

Posted: May 19, 2014 by oldbrew in Astrophysics, solar system dynamics
Neptune - Earth comparison [credit: Wikipedia]

Neptune – Earth comparison [credit: Wikipedia]

Last year we had an interesting discussion here at the Talkshop on the topic of Saturn’s ‘polar hexagon’ which has been the subject of many photos and videos by the Cassini orbiter.

During the discussion Dr Carolyn Porco, a NASA scientist, dropped by to explain a few points about the properties of that phenomenon – images and comments here:

Stunning new image of Saturn’s polar hexagonal jet stream

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Image

High precision model of precession and nutation of the asteroids Ceres, Vesta, Eros, Steins, and Itokawa

A. Petit, J. Souchay and C. Lhotka

Observatoire de Paris and University of Rome

http://dx.doi.org/10.1051/0004-6361/201322905 (open access with registration)

“Abstract

Context. Several asteroids have recently been visited by spacecrafts that give us precious information and new constraints on their physical and rotational properties. In parallel, there are already several well-established theories to model the rotational motion of a rigid body, but accurate models of the rotational motion of asteroids have been poorly investigated so far. … “

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Big Bang  [credit: Wikipedia]

Big Bang
[credit: Wikipedia]


An orchestrated media blitz to push claims that ‘spectacular’ evidence of cosmic inflation had been detected by researchers could be turning sour only a few weeks later.

The story broke in a blaze of publicity – but before peer review:
‘First direct evidence for cosmic inflation announced’

Now it seems the BICEP2 results are looking a bit flabby according to one commentator close to the action.

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From Discovery.com

Time flies on beta Pictoris b, a behemoth gas planet orbiting a young neighbor star about 63 light-years from Earth.

A day there lasts just eight hours, making beta Pic b a faster spinner than even Jupiter, which rotates in 10 hours. Pic b is the first planet beyond the solar system to have its rotational rate clocked, scientists said in an article published in this week’s Nature.

Technically, what is interesting is that it was so easy to do these observations,

lead researcher Ignas Snellen, with Leiden University, Netherlands, wrote in an email to Discovery News.

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Image

New paper finds solar activity related to the polar vortex & jet stream variability

This paywalled JGR paper seems to have created a fuss in some circles.

The concept of solar / polar linkage makes sense in my opinion if there is a magnetic connection to this. Others disagree.

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Earth-Moon-Phi

Let’s take a virtual trip to the Moon with an idea of Johannes Kepler to guide us. In this image we have the Moon placed next to the Earth – what are we seeing?

The triangle has one side running from the centre of the Moon to the centre of the Earth, one running at right angles to it from the Earth’s centre point to the edge of the Earth, and the third side completing the triangle.

Since it’s a right-angled triangle, the third side is also the hypotenuse of a Pythagorean triangle. But it’s a bit more than that too.

According to NASA’s Moon factsheet, the ratio of the equatorial radius of the Moon to that of the Earth is 0.2725.

That means if the Earth radius is given a value of 1, the Moon radius will be 0.2725 on the same scale (i.e. as a ratio), making a combined Earth+Moon radius of 1.2725, which is almost identical to the square root of phi (1.27202) – a 99.96% match.

http://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html

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Talkshop readers will remember that some time ago, we had a guest post from Raghu Singh about a gravity theory he has been developing. Since the discussion here, Raghu got his paper published in the General Science journal and received a lot of feedback. That led to some reworking and he has now re-written his paper. The latest version of his model has had some theoretical success. In email Raghu tells me:

Gravity-1“My primary goal has been to explore gravitational radiation. More than one theory can explain several gravitational phenomena – except gravitational radiation, which one and only one theory shall explain. Physics does not have that one experimentally confirmed theory of gravitational radiation as of now. Astrophysicists claim, rightly so, that there are indirect evidences of the existence of gravitational waves, but those are not evidences on the physics of gravitational radiation (i.e., its emission, propagation, structure, speed, and polarization).

I used the revised model to calculate the orbital shrinking of pulsars PSR B1913+16, the results are astonishing. The model yields 3.71 mm/period; general relativity yields 3.5 mm/period. This is the ultimate test for any gravitation theory. Hulse and Taylor received Nobel Prizes for applying general relativity to the orbits of PSR B1913+16

Physics has been waiting for several decades just to detect gravitational radiation; must it wait longer? Our increasingly vast knowledge of the strong nuclear, the weak nuclear, and electromagnetic interactions notwithstanding, deciphering gravitation is essential to the survival of the species beyond the solar system and the Milky Way – as the great Professor Hawking would like to say.

A Constructive Model of Gravitation

Raghubansh P. Singh

Abstract
The paper presents a physical model in which mass fields and momentum fields mediate gravitational interactions.

The model addresses: Gravitational interaction between masses, between mass and energy, and between photons; Gravity’s effect on spectral lines, time periods of atomic clocks, and lengths of material rods; Gravitational radiation; Mercury’s orbital precession rate; and the Pioneer effect. Of particular importance, it calculates gravitational radiation power emissions from the moon, the planets of the sun, and the binary pulsars PSR B1913+16. It reflects upon time.

The model rediscovers the initial predictions of general relativity. It makes new predictions:

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