APOD: Zodiacal Light and Mars (2021 Mar 11)

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APOD: Zodiacal Light and Mars (2021 Mar 11)

Post by APOD Robot » Thu Mar 11, 2021 5:05 am

Image Zodiacal Light and Mars

Explanation: Just after sunset on March 7, a faint band of light still reaches above the western horizon in this serene, rural Illinois, night skyscape. Taken from an old farmstead, the luminous glow is zodiacal light, prominent in the west after sunset during planet Earth's northern hemisphere spring. On that clear evening the band of zodiacal light seems to engulf bright yellowish Mars and the Pleiades star cluster. Their close conjunction is in the starry sky above the old barn's roof. Zodiacal light is sunlight scattered by interplanetary dust particles that lie near the Solar System's ecliptic plane. Of course all the Solar System's planets orbit near the plane of the ecliptic, within the band of zodiacal light. But zodiacal light and Mars may have a deeper connection. A recent analysis of serendipitous detections of interplanetary dust by the Juno spacecraft during its Earth to Jupiter voyage suggest Mars is the likely source of the dust that produces zodiacal light.

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Re: APOD: Zodiacal Light and Mars (2021 Mar 11)

Post by Ann » Thu Mar 11, 2021 6:03 am

A non-collimated lightsaber beam is hitting the Pleiades and Mars! Aldebaran and the Hyades, to the upper left of Pleiades and Mars, narrowly escape getting hit! Note that Aldebaran and Mars look like twins, because of their identical apparent luminosity and color! The Alpha Persei moving cluster, to the upper right of the Pleiades, is looking good!

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Re: APOD: Zodiacal Light and Mars (2021 Mar 11)

Post by Knight of Clear Skies » Thu Mar 11, 2021 12:17 pm

Didn't know the zodiacal light might be connected to Mars. So in a loose sense, Mars could be said to have a ring system that spans the solar system.
Caradon Observatory, Cornwall, UK.

dww

Re: APOD: Zodiacal Light and Mars (2021 Mar 11)

Post by dww » Thu Mar 11, 2021 12:18 pm

The chances of anything coming from Mars are a million to one, they said ....
But still they come! Though only as dust. So far.

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Re: APOD: Zodiacal Light and Mars (2021 Mar 11)

Post by De58te » Thu Mar 11, 2021 2:42 pm

I am just thinking about the transitory nature of the descriptive adjectives in Astronomy. We are told that the barn is an old barn. And indeed it is old compared to the some 8 minute old Zodiacal light. But can we say the barn is old compared to the 115 million year old Pleiades? For the Pleiades in their view looking down at the barn it is just a young whippersnapper. But then consider the 4 and a half billion year old Mars. For most of Mars' lifetime the Pleiades never existed and are themselves young baby whippersnappers!

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Re: APOD: Zodiacal Light and Mars (2021 Mar 11)

Post by neufer » Thu Mar 11, 2021 2:47 pm

https://en.wikipedia.org/wiki/Zodiacal_light wrote:
<<The source of zodiacal light dust has been long debated. Until recently, it was thought that the dust originated from the tails of active comets and from collisions between asteroids in the asteroid belt. Many of our meteor showers have no known active comet parent bodies. Over 85 percent of the dust is attributed to occasional fragmentations of Jupiter-family comets that are nearly dormant. Jupiter-family comets have orbital periods of less than 20 years and are considered dormant when not actively outgassing, but may do so in the future. The first fully dynamical model of the zodiacal cloud demonstrated that only if the dust was released in orbits that approach Jupiter, is it stirred up enough to explain the thickness of the zodiacal dust cloud. The dust in meteoroid streams is much larger, 300 to 10,000 micrometres in diameter, and falls apart into smaller zodiacal dust grains over time.

The Poynting–Robertson effect forces the dust into more circular (but still elongated) orbits, while spiralling slowly into the Sun. Hence a continuous source of new particles is needed to maintain the zodiacal cloud. Cometary dust and dust generated by collisions among the asteroids are believed to be mostly responsible for the maintenance of the dust cloud producing the zodiacal light and the gegenschein.

Particles can be reduced in size by collisions or by space weathering. When ground down to sizes less than 10 micrometres, the grains are removed from the inner Solar System by solar radiation pressure. The dust is then replenished by the infall from comets. Zodiacal dust around nearby stars is called exozodiacal dust; it is a potentially important source of noise for directly imaging extrasolar planets. It has been pointed out that this exozodiacal dust, or hot debris disks, can be an indicator of planets, as planets tend to scatter the comets to the inner Solar System.

In 2015, new results from the secondary ion dust spectrometer COSIMA on board the ESA/Rosetta orbiter confirmed that the parent bodies of interplanetary dust are most probably Jupiter-family comets such as comet 67P/Churyumov-Gerasimenko. Data from the the Juno mission indicate that the dust close to Earth has a local origin in the inner Solar System, best fitting the planet Mars as a source.>>
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Re: APOD: Zodiacal Light and Mars (2021 Mar 11)

Post by orin stepanek » Thu Mar 11, 2021 3:32 pm

ZodiacalLightBarn1024.jpg

First thing I noticed was the Pleiades star cluster and Mars! Of course Orion Constellation! I have trouble finding Saiph! :shock:
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Re: APOD: Zodiacal Light and Mars (2021 Mar 11)

Post by Sa Ji Tario » Thu Mar 11, 2021 3:47 pm

I think it is the star attached to the left frame

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Re: APOD: Zodiacal Light and Mars (2021 Mar 11)

Post by Astronymus » Thu Mar 11, 2021 4:44 pm

First thing I noticed are the photoshop traces in the gras. Force of habit. :facepalm:
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Shergottites

Post by neufer » Fri Mar 12, 2021 3:09 am

https://en.wikipedia.org/wiki/Asteroid_belt wrote:
<<The high population of the asteroid belt makes for a very active environment, where collisions between asteroids occur frequently (on astronomical time scales). Collisions between main-belt bodies with a mean radius of 10 km are expected to occur about once every 10 million years. A collision may fragment an asteroid into numerous smaller pieces (leading to the formation of a new asteroid family).

Along with the asteroid bodies, the asteroid belt also contains bands of dust with particle radii of up to a few hundred micrometres. This fine material is produced, at least in part, from collisions between asteroids, and by the impact of micrometeorites upon the asteroids. Due to the Poynting–Robertson effect, the pressure of solar radiation causes this dust to slowly spiral inward toward the Sun.

The combination of this fine asteroid dust, as well as ejected cometary material, produces the zodiacal light. Asteroid particles that produce the visible zodiacal light average about 40 μm in radius. The typical lifetimes of main-belt zodiacal cloud particles are about 700,000 years. Thus, to maintain the bands of dust, new particles must be steadily produced within the asteroid belt. It was once thought that collisions of asteroids form a major component of the zodiacal light. However, computer simulations by Nesvorný and colleagues attributed 85 percent of the zodiacal-light dust to fragmentations of Jupiter-family comets, rather than to comets and collisions between asteroids in the asteroid belt. At most 10 percent of the dust is attributed to the asteroid belt.>>
https://en.wikipedia.org/wiki/Tissint_meteorite wrote: <<On July 18, 2011, around 2 AM local time, a bright fireball was observed by several people in the Oued Drâa valley, east of Tata, Morocco. One observer reported that the fireball was initially yellow in color, then turned green, illuminating the entire area before it appeared to break into two pieces; two sonic booms were heard over the valley. In October 2011, nomads began to find very fresh, fusion-crusted stones in a remote area of the Oued Drâa intermittent watershed. The Tissint meteorite was named after the town of Tissint, 48 kilometres away from the fall site. Dozens of fragments with masses ranging from 0.2 to 1,282 grams were collected, totaling roughly 12–15 kilograms.

The meteorite was ejected from the surface of Mars between 700,000 and 1,1 million years ago. Tissint appears to be derived from a deep mantle source region that was unlike any of the other known Martian shergottite meteorites. The material is highly shocked and indicates it was ejected during the largest impact excavation in record. Given the widely dispersed shock melting observed in Tissint, alteration of other soft minerals (carbonates, halides, sulfates and even organics), especially along grain boundaries, might have occurred. This may in part explain the lack of such minerals in Tissint, but it is unknown if it is of biotic origin.

The meteorite fragments were recovered within days after the fall, so it is considered an "uncontaminated" meteorite. The meteorite displays evidence of water weathering, and there are signs of elements being carried into cracks in the rocks by water or fluid, which is something never seen before in a Martian meteorite. Specifically, scientists found carbon and nitrogen-containing compounds associated with hydrothermal mineral inclusions. One team reported measuring an elevated carbon-13 ratio, while another team reported a low 13C ratio as compared to the content in Mars' atmosphere and crust, and suggested that it may be of biological origin, but the researchers also noted that there are several geological processes that could explain that without invoking complex life-processes; for example, it could be of meteoritic origin and would have been mixed with Martian soil when meteorites and comets impact the surface of Mars, or of volcanic origin.

The data on refractory trace elements, sulfur and fluorine as well as the data on the isotopic composition of nitrogen, argon and carbon released upon heating from the matrix and glass veins in the meteorite unambiguously indicate the presence of a Martian surface component including trapped atmospheric gases. So, the influence of in situ Martian weathering can be distinguished from terrestrial contamination in the meteorite. The Martian weathering features in Tissint are compatible with the results of spacecraft observations of Mars, and Tissint has a cosmic ray dating exposure age of 0.7 ± 0.3 Ma—consistent with the reading of many other shergottites, notably EETA79001, suggesting that they were ejected from Mars during the same event.

The overall composition of the Tissint meteorite corresponds to that of aluminium-poor ferroan basaltic rock, which likely originated as a result of magmatic activity at the surface of Mars. These basalt then underwent weathering by fluids, which deposited minerals enriched in incompatible elements in fissures and cracks. A later impact on the surface of Mars melted the leached material forming black glassy veins. Finally shergottites were ejected from Mars about 0.7 million years ago.>>
https://en.wikipedia.org/wiki/Martian_meteorite#Shergottites wrote: <<Roughly three-quarters of all Martian meteorites can be classified as shergottites. They are named after the Shergotty meteorite, which fell at Sherghati, India in 1865. Shergottites are igneous rocks of mafic to ultramafic lithology. They fall into three main groups, the basaltic, olivine-phyric (such as the Tissint group found in Morocco in 2011) and Lherzolitic shergottites, based on their crystal size and mineral content. They can be categorised alternatively into three or four groups based on their rare-earth element content. These two classification systems do not line up with each other, hinting at complex relationships between the various source rocks and magmas from which the shergottites formed.>>
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Re: APOD: Zodiacal Light and Mars (2021 Mar 11)

Post by VictorBorun » Fri Mar 12, 2021 4:33 am

Knight of Clear Skies wrote:
Thu Mar 11, 2021 12:17 pm
Didn't know the zodiacal light might be connected to Mars. So in a loose sense, Mars could be said to have a ring system that spans the solar system.
Or maybe it's a comet tail of Mars

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Re: APOD: Zodiacal Light and Mars (2021 Mar 11)

Post by VictorBorun » Fri Mar 12, 2021 4:50 am

I wonder why
1) zodiacal light is brightest in the two arcs of zodiacal circle: one centered in the Sun and the other is opposite to the Sun
2) zodiacal light is best viewed after the sunset on the equinox of the Northern hemishpere's spring or before the sunrise on the equinox of the Northern hemishpere's autumn

1) The dusty ring-tail of Mars is in a circular orbit around the Sun and must shine equally bright all along the ring. For an observer on Earth such dusty tail-ring should look uniformly bright and differ only in the width: the farthest parts seen near the Sun should look the most narrow (which contradicts the pic in this post?)
2) How can an observation before the dawn differ from one after the sunset, and how can an observation in the Northern hemishpere differ from one in the Soutern hemishpere ?

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Zodiacal Light and Mojave?

Post by neufer » Sat Mar 27, 2021 10:00 pm

https://en.wikipedia.org/wiki/Mojave_(crater) wrote:
Click to play embedded YouTube video.
<<Mojave is a 58 km diameter impact crater in the Oxia Palus quadrangle of Mars. The crater is located at 7.5° N and 33.0° W within the Martian Xanthe Terra region. Some parts of the crater display a high concentration of closely spaced pits. Pits show little or no evidence of rims or ejecta. The pits are so close to each other that adjacent pits often share the same wall. It is believed that the pits form from steam produced when the heat from the impact process interacts with ice in the ground. Mojave is a rayed crater, another indication of its youth, and is the largest such crater on Mars. Based on crater counts of its ejecta blanket, it is thought to be about 3 million years old. It is believed to be the most recent crater of its size on Mars, and has been identified as the probable source of the shergottite meteorites collected on Earth.

The depth of Mojave is approximately 2,600 meters. Based on its ratio of depth to diameter, researchers believe it is very young. It is not old enough to have accumulated much material and start to fill. Its relatively undegraded state helps scientists model impact processes on Mars. If one measures the diameter of a crater, the original depth can be estimated with various ratios. Because of this relationship, researchers have found that many Martian craters contain a great deal of material; much of it is believed to be ice deposited when the climate was different.>>
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