Tag: science

Baffling ridges on Mars

1:01 pm

Baffling ridges on Mars
Click for full image.

Today’s cool image is one of my “what the heck?” photos. The picture to the right, cropped and reduced to post here and taken on September 3, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), shows a strange dune field of many parallel long dunes, cross-cut by larger ridges.

Are the larger ridges dunes? Or are they some form of volcanic or tectonic ridge, which is also very typical of this region, called Tempe Terra and located in the transition zone between the southern cratered highlands and the northern lowland plains?

Or are they eskers, ridges frequently found in places that were once covered by glaciers? At 35 degrees north latitude, it would not be surprising to see glacial features here, but as far as I can tell, the full image has no obvious such features.
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Radar images of Apophis during its March close approach of Earth

9:45 am

Apophis as seen by radar March 9, 2021
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Using two radar dishes, Green Bank in West Virginia and Goldstone in California, astronomers were able to produce radar images of the asteroid Apophis during its most recent close fly-by of Earth on March 10th.

The image to the right, cropped and reduced to post here, shows Apophis on March 9th. If you go to the full image you can also see the March 10th and 11th images, which appear to show the asteroid in different orientations as it rotated.

These images represent radar observations of asteroid 99942 Apophis on March 8, 9, and 10, 2021, as it made its last close approach before its 2029 Earth encounter that will see the object pass our planet by less than 20,000 miles (32,000 kilometers). The 70-meter radio antenna at the Deep Space Network’s Goldstone Deep Space Communications Complex near Barstow, California, and the 100-meter Green Bank Telescope in West Virginia used radar to precisely track Apophis’ motion. At the time of these observations, Apophis was about 10.6 million miles (17 million kilometers) from Earth, and each pixel has a resolution of 127 feet (38.75 meters).

The data obtained has firmly removed any chance Apophis will impact the Earth in the next 100 years. However, it still could hit us late in the 22nd century.

These observations were originally planned to also include data from the Arecibo Observatory, but that telescope was destroyed in December when its instrument platform collapsed. If it had been operational, these radar images would have had much better resolution.

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Ice-filled crater in Mars’ glacier country

2:06 pm

Crater filled with ice
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Cool image time! The photo to the right, cropped and reduced to post here and taken on January 7, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), provides us a perfect example of the kind of glacial feature that scientists find routinely in the 30 to 60 degree mid-latitude bands on Mars. In this case the crater is in the northern reaches of a chaos region dubbed Nilosyrtis Mensae, the easternmost mensae region of what I dub glacier country on Mars.

When first identified scientists named this concentric crater fill, a purposely vague term that is only descriptive because they then did not know what it was made of, though they had their suspicions that it was buried glacial ice. Since then radar data has routinely confirmed that there is ice in such filled craters, making this particular glacial feature one of the most prevalent in those mid-latitude bands.

You can see a quite similar ice-filled crater, also in Nilosyrtis, in an earlier post from October 2020. While that earlier crater was on the southern edge of Nilosyrtis, today’s crater is about 300 miles almost due north, near the region’s northern fringe. In between are lots of similar glacial features, sometimes in craters, sometimes flowing off the slopes of mesas, and sometimes flow features in the open canyons between.

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Mars’ polar ice canyons are young and the source for mid-latitude ice

9:40 am

Mars' north pole icecap
Mars’ north polar ice cap.

Scientists have now proposed that the giant ice canyons seen at the edges of Mars’ polar ice caps are very young and are also the source of the water that sublimates away when the planet’s rotational tilt (its obliquity) is high, to fall as snow in the mid-latitudes where it forms the glaciers and ice sheets we now find there.

The image to the right, reduced to post here, shows the entire north pole ice cape on the left, with its spiral canyons. The two inserts on the bottom show for scale Hawaii’s Big Island and the Grand Canyon. From the release:

“Erosion formed a huge ice canyon system, and that erosion is a source of the long-known mid-latitude mantles on Mars,” said Rodriguez, lead author of “North polar trough formation due to in‑situ erosion as a source of young ice in mid‑latitudinal mantles on Mars” that appears in Nature Scientific Reports.

The troughs are arranged in a vast spiral pattern covering an area the size of Texas. We find that their growth lateral to katabatic wind (wind that carries high-density colder air from a higher elevation down a slope) directions produced widespread simple intersections, from which the highly complex spiral arrangement emerged, Rodriguez said. “The spiral pattern seen in the troughs is basically an erosional byproduct,” he said. “As the pits grow and intersect over a pre-existing dome-shaped polar cap, the spiral pattern emerges.

“It has long been proposed that sublimation of water ice from the north polar cap during high-obliquity cycles was an essential source of the planet’s mid-latitude icy plains. Our finding identifies the troughs as direct evidence of those sublimation phases,” Rodriguez said.

These spiral trough features formed very recently, in geologic terms: between a few million and 50,000 years ago, Rodriguez said.

This hypothesis, if true, is very important in understanding the long term geological history of Mars. The present theory is that when the obliquity rises to as high of 60 degrees, compared to today’s 25 degrees (similar to Earth’s), the mid-latitudes are colder than the poles, and the ice at the poles then migrates to the mid-latitudes. This paper gives us the place at the poles where the icecap shrinks as that ice sublimates away.

Knowing that these polar canyons are young and the source of the mid-latitude ice scientists can now begin to write the geological history of the polar ice caps themselves. They can also use this information to maybe determine whether the caps are presently in a steady state, as now believed, or growing or shrinking.

The youth of these canyons also suggests that any mid-latitude ice from them is also young, and thus more likely pure water unpoisoned by the toxic perchlorates found in many places on the Martian surface. It will thus be easier to obtain pure drinkable water from them.

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The 1st image of a black hole’s magnetic field

8:54 am

The magnetic field lines of a black hole

Using the data from the first image of a black hole, obtained in 2019, scientists have now extracted evidence of the magnetic field lines near the event horizon, and from this produced the first image of such lines.

The image to the left, reduced to post here, shows the spiraling magnetic field lines against the bright event horizon ring.

As the Event Horizon Telescope (EHT) team describes today in a pair of papers in Astrophysical Journal, the new picture uses the same data as in the original image, produced from a series of observations in 2017 of the supermassive black hole at the core of nearby galaxy M87, using the combined collecting power of eight radio observatories across the world. To extract the polarization information, the data have gone through many months of additional analysis.

The scientists also note that the orientation of the field lines might eventually help explain the jets being thrown from its poles.

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Layers upon layers of Martian volcanic ash

2:05 pm

Layers upon layers of Martian volcanic ash
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Today’s cool image provides I think a hint at the vast amount of time that has passed on Mars, allowing uncounted major events to occur which each lay down a bit of the geological history, a history that is now piled up on the surface so deeply that it will take decades of research to untangle it.

The photo to the right, cropped and reduced to post here, was taken on December 23, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the layered nature of the Medusae Fossae Formation, the largest volcanic ash deposit on Mars (about the land area of India) and thought by some to be the source of most of the dust across the entire red planet.
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Scientists: Mars is losing water seasonally through its atmosphere

9:38 am

The uncertainty of science: Two new studies using data Europe’s Trace Gas Orbiter and Mars Express orbiters have found that Mars is losing water seasonally through its atmosphere.

The studies also found that global dust storms accelerate the process.

Anna and colleagues found that water vapour remained confined to below 60 km when Mars was far from the Sun but extended up to 90 km in altitude when Mars was closest to the Sun. Across a full orbit, the distance between the Sun and the Red Planet ranges from 207 million to 249 million km.

Near the Sun, the warmer temperatures and more intensive circulation in the atmosphere prevented water from freezing out at a certain altitude. “Then, the upper atmosphere becomes moistened and saturated with water, explaining why water escape rates speed up during this season – water is carried higher, aiding its escape to space,” adds Anna.

In years when Mars experienced a global dust storm the upper atmosphere became even wetter, accumulating water in excess at altitudes of over 80 km.

But wait, didn’t planetary scientists just announce that Mars hasn’t lost its water through the atmosphere, but instead lost it when it became chemical trapped in the planet’s soil? Yup, they did, but that was a model based on new ground data. This new result is based on atmospheric data.

Or to put it another way, the model was incomplete. While it could be true that a large bulk of Mars’ water is trapped chemically in the ground, that is not proven, only hypothesized. What has been proven, and is now confirmed by these two studies, is that, depending on weather and season, the water of Mars does leak into its upper atmosphere where it can escape into space, never to return.

What remains unknown is how much water escaped into space, and when. Moreover, the ground-based model could still be right, even if it is true that Mars is losing water through its atmosphere. At the moment the data is too incomplete to answer these questions with any certainty.

Meanwhile, this press release once again gives the false impression that the only water left on Mars is at its poles (and in this case, only the south pole). This is not accurate, based on numerous studies finding evidence of buried ice and glaciers everywhere on the planet down to the 30th latitude, in both the north and south hemispheres. Mars might have far less water now than it did billions of years ago, but it still has plenty, and that water is not found only at the poles.

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A data-based broad look at the entire COVID epidemic, one year later

2:24 pm

The Scream by Edvard Munch
The Scream by Edvard Munch

One year ago I posted an essay entitled COVID-19: the unwarranted panic. At that time we had just begun a “15-day-lockdown” to slow the spread of the virus, a lockdown that has ended up lasting a year with literally no signs of ending, even though vaccines for the coronavirus are now available and are being administrated widely to millions.

In that essay I reviewed four early science studies that provided some solid initial data about the coronavirus, all of which strongly suggested that it was not the plague many government healthy officials at that time were proclaiming it to be. Instead, these studies showed that it was only a threat to the elderly sick, that it was relatively harmless to a young population, and that the death rate was low, likely well below 1% and possibly very comparable to the flu.

These data strongly suggested to me that lockdowns, social distancing, masks, and restrictions on the freedom of the healthy and young were all a bad idea. Better to follow the traditional response to past such epidemics in which you quarantine the sick, protect the vulnerable (the elderly), and allow everyone else to go about their lives as normal.

We did not do this, however. Instead, as a society we chose in the past year to do the exact oppose, imposing strict lockdowns, mandating social distancing and mask use everywhere, while quarantining the healthy. We did this based on the worst scenarios and models put forth by health officials, who firmly believed COVID-19 was far worse than any past epidemic, and required a new, radical, and much harsher response.

I now want to ask, one year later: Whose conclusions about the seriousness of COVID-19 were more accurate? Was it just another type of flu, though maybe somewhat worse, as I posited, or was it the deadly pestilence predicted by the world’s health authorities?
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Twisted and tilted bedrock in Martian crater

11:36 am

tilted strata in Martin Crater
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Cool image time! The photo to the right, rotated cropped, and reduced to post here, is only a small example of the strangely tilted and twisted strata in the central peak region of 38-mile-wide Martin Crater on Mars. The full image shows more.

The picture was taken on January 12, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The section I’ve cropped out shows a series of stratified strata that are are not only significantly tipped from the horizontal, but have also been bent and deformed.

The crater itself is located about 260 miles south of Valles Marineris, as shown on the overview map below.
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Perseverance dumps debris shield in preparation for Ingenuity deployment

8:59 am

Dumped debris shield under Perseverance
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On March 21st the Perseverance engineering team released the debris shield that had been attached to the bottom of the rover to protect the Ingenuity helicopter during its journey to Mars, and thus began the deployment process for releasing the helicopter itself.

The photo to the right, cropped and reduced to post here, shows that debris shield on the ground. The rover will next drive away from this spot and find the flat area where the helicopter will be placed on the ground for its April flight.

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Yutu-2 & Chang’e-4 complete 28th lunar day on Moon

8:42 am

The new colonial movement: China’s lunar rover Yutu-2 and its lander Chang’e-4 have successfully completed their 28th lunar day on the far side of the Moon, and have been placed in hibernation for the long lunar night.

According to this article from China’s state-run press, Yutu-2 has now traveled 683 meters (2,241 feet) since its landing. In the past two lunar days the rover has traveled about 180 feet, continuing its journey to the northwest away from Chang’e-5. Their pace continues to be about 80 to 100 feet per lunar day.

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A visit to Cydonia on Mars

1:00 pm

Strange geology in Cydonia on Mars
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Cool image time! The Cydonia region on Mars, located at around 30-40 degrees north latitude in the northern lowland plains just beyond the transition zone up to the southern cratered highlands, is well known to many on Earth because it was here that the Viking-1 orbiter took a picture of a mesa that, because of the sun angle, made its shadows resemble a face. Thus was born the “Face on Mars” that consumed the shallow-minded among us — and thus the culture, media, and Hollywood — absurdly for decades, until Mars Global Surveyor took the first high resolution image and proved without doubt what was really obvious from the beginning, that it was nothing more than a mesa.

Cydonia however remains a very intriguing region of Mars, mostly because it is home to a lot of strange geology, as shown by the photo to the right, rotated, cropped, and reduced to post here. Taken on January 16, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), it shows some of that strange and inexplicable geology.

While Cydonia is inside that 30-60 degree latitude band where MRO has imaged numerous glacial-type features, I do not know if many such features have been found there. Except for the pits and depressions in the photo’s lower right — which suggest decay in an ice sheet — little else at first glance in the picture clearly invokes any of the obvious glacial features one comes to expect. There appear to be what might be lobate flows in the image’s center going from the west to the east, but if they are glacial, they are so decayed to as leave much doubt.

The overview image below shows where Cydonia is on Mars, and helps explain partly what is found here.
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