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A close encounter with a mysterious moon

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<div data-thumb=”https://scx1.b-cdn.net/csz/news/tmb/2022/a-close-encounter-with.jpg” data-src=”https://scx2.b-cdn.net/gfx/news/hires/2022/a-close-encounter-with.jpg” data-sub-html=”The High Resolution Stereo Camera (HRSC) onboard the ESA spacecraft Mars Express took this image of Phobos using the HRSC nadir channel on 7 March 2010, HRSC Orbit 7915. This image has additionally been enhanced photometrically for better bringing features in the less illuminated part. Resolution: about 4.4 meters per pixel. Credit: ESA/DLR/FU Berlin (G. Neukum), CC BY-SA 3.0 IGO“>

<img src=”https://scx1.b-cdn.net/csz/news/800a/2022/a-close-encounter-with.jpg” alt=”A close encounter with a mysterious moon” title=”The High Resolution Stereo Camera (HRSC) onboard the ESA spacecraft Mars Express took this image of Phobos using the HRSC nadir channel on 7 March 2010, HRSC Orbit 7915. This image has additionally been enhanced photometrically for better bringing features in the less illuminated part. Resolution: about 4.4 meters per pixel. Credit: ESA/DLR/FU Berlin (G. Neukum), CC BY-SA 3.0 IGO” width=”800″ height=”530″>
The High Resolution Stereo Camera (HRSC) onboard the ESA spacecraft Mars Express took this image of Phobos using the HRSC nadir channel on 7 March 2010, HRSC Orbit 7915. This image has additionally been enhanced photometrically for better bringing features in the less illuminated part. Resolution: about 4.4 meters per pixel. Credit: ESA/DLR/FU Berlin (G. Neukum), CC BY-SA 3.0 IGO

In 1877, American astronomer Asaph Hall discovered two small moons circling the planet Mars, later named Phobos and Deimos after the Greek for “fear” and “panic.”

But it was excitement, rather than fear and panic, that characterized the close encounter with Phobos made by ESA’s Mars Express spacecraft in the run up to Halloween this year. The recent flyby of the larger Martian moon offered the perfect opportunity to test one of the 19-year-old spacecraft’s latest upgrades.

The MARSIS instrument on Mars Express was originally designed to study the internal structure of Mars. As a result, it was designed for use at the typical distance between the spacecraft and the planet’s —more than 250 km.

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But it recently received a major software upgrade that allows it to be used at much closer distances and which could help to shed light on the mysterious origin of the moon Phobos.

“During this flyby, we used MARSIS to study Phobos from as close as 83 km,” says Andrea Cicchetti from the MARSIS team at INAF. “Getting closer allows us to study its structure in more detail and identify important features we would never have been able to see from further away. In future, we are confident we could use MARSIS from closer than 40 km. The orbit of Mars Express has been fine-tuned to get us as close to Phobos as possible during a handful of flybys between 2023 and 2025, which will give us great opportunities to try.”

“We didn’t know if this was possible,” says Simon Wood, Mars Express flight controller at ESA’s ESOC operations center, who oversaw the upload of the new software to the ESA spacecraft. “The team tested a few different variations of the software, with the final, successful tweaks uploaded to the spacecraft just hours before the flyby.”

Artist’s impression of water under the martian surface. If underground aquifers like that really do exist, Mars Express has a good chance of finding them. The implications for human exploration and eventual colonisation of the red planet would be far-reaching. Credit: Medialab, ESA 2001

Mysterious origins

MARSIS, famous for its role in the discovery of signs of liquid water on the Red Planet, sends low-frequency radio waves towards Mars or Phobos, using its 40-meter long antenna.

Most of these waves are reflected from the body’s surface, but some travel through and are reflected at boundaries between layers of different materials below the surface.

By examining the reflected signals, scientists can map the structure below the surface and study properties such as the thickness and composition of the material.

For Mars, this could reveal different layers of ice, soil, rock or water. But the internal structure of Phobos is more of a mystery, and the upgrade to MARSIS could offer important insight.

“Whether Mars’ two small moons are captured asteroids or made of material ripped from Mars during a collision is an open question,” says ESA Mars Express scientist Colin Wilson. “Their appearance suggests they were asteroids, but the way they orbit Mars arguably suggests otherwise.”

“We are still at an early stage in our analysis,” says Andrea. “But we have already seen possible signs of previously unknown features below the moon’s surface. We are excited to see the role that MARSIS might play in finally solving the mystery surrounding Phobos’ origin.”

A close encounter with a mysterious moon
The MARSIS instrument on ESA’s Mars Express spacecraft uses its recently upgraded software to peer beneath the surface of the martian moon Phobos. Credit: INAF – Istituto Nazionale di Astrofisica

What does this image show?

The top-right image shows the “radargram” acquired by MARSIS during the of Phobos on 23 September 2022. A radargram reveals the “echoes” created when the radio signal emitted by MARSIS bounces off something and returns to the instrument. The brighter the signal, the more powerful the echo.

The continuous bright line shows the echo from the moon’s surface. The lower reflections are either “clutter” caused by features on the moon’s surface, or, more interestingly, signs of possible structural features below the surface (e).

“Section A–C was recorded using an older configuration of the MARSIS software,” says Carlo Nenna, MARSIS on-board software engineer at Enginium, who is implementing the upgrade. “The new configuration was prepared during the ‘technical gap’ and successfully used for the very first time from D–F.”

The left and bottom-right images show the path of the observation across the surface of Phobos.

Provided by
European Space Agency

 

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What Are Fast Radio Bursts? – Worldatlas.com

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The universe is full of mystery. No matter how much becomes known about the cosmos, there always seems to be more that is unknown. Any time a question is answered, more questions seem to arise, and so the process of scientific discovery becomes never ending. There are many examples of what is unknown about the cosmos, yet one perfect example is a phenomenon known as Fast Radio Bursts (FRB). As the name suggests, an FRB is a burst of radio waves that originate from the depths of interstellar space. They usually only last up to three seconds long, yet whatever releases them emits more energy in one second than our sun does every day. This suggests that FRBs are created by high energy processes, yet exactly what causes them remains unknown. 

Where Do FRBs Come From?

Most FRBs orignate in distant galaxies. Image credit: NASA/ESA

Most FRBs detected originate beyond the Milky Way Galaxy, yet some have been detected within our galaxy. To date, astronomers have detected around 500 FRBs, yet there remains no consensus on what actually creates them. That isn’t to say there aren’t any possible explanations, however. Some popular theories claim that FRBs originate from stellar remnants such as neutron stars or black holes. Other theories posit that they may originate from collisions between black holes or neutron stars. Another interesting theory is that FRBs come from a type of stellar remnant called a magnetar. A magnetar is a type of neutron star that has an exceptionally strong magnetic field and emits high amounts of x-rays and gamma rays, and some FRBs have been traced back to regions around magnetars. It’s quite possible that FRBs form from multiple different events, with no single phenomenon able to explain the origin of every FRB. 

Alien Origin

Galaxy Hubble
Hubble image of a distant galaxy. Image credit: NASA/ESA

Whenever astronomers detect signals of unknown origin, there is always the question of whether or not the signal originated from another civilization. Ever since humans began using technology to transmit signals around the world, some of the signals leak into space and travel at the speed of light. Any civilization that happens to be pointing a radio telescope in the right direction at the right time would detect our signals. Assuming other intelligent civilizations develop radio technology, they too would emit signals out into space that could be detected by us. Thus, some astronomers have wondered if some FRBs are in fact the radio signals from another civilization. Interestingly, this isn’t the first time this has happened. When astronomers discovered the first pulsars, they thought they had come across an alien signal, yet it later turned out to be a rapidly rotating neutron star. In the case of FRBs, it is unlikely they originate from another intelligent species. This is mainly due to the fact that they do not appear to come directly from other solar systems, and the bursts themselves contain so much energy that it seems unlikely a civilization would be creating them. Rather, a natural explanation is more likely, yet it still remains unknown exactly where FRBs come from.

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How Old Is The Sun? – Worldatlas.com

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The sun formed around 4.6-billion years ago, and all the planets formed within the next 100-million years. The age of the sun and the planets is one of the most widely accepted facts about our solar system, and the reason for this is that every line of evidence points to the same age. How is the age of the sun determined?

Finding The Oldest Thing In The Solar System

One way to determine the approximate age of the sun is to find the oldest object in the solar system. Fortunately, there are countless objects that formed along with the sun, such as asteroids, meteors, and planetesimals. These forms of planetary debris remain virtually unchanged for billions of years, and by using radiometric dating methods, scientists can determine their age, in turn directly telling us how old the sun is. Radiometric dating uses precise chemicals to determine the age of rocks, and it works by using something called a half-life. For example, carbon-14 dating is a reliable method for dating things like fossils, as carbon-14 is only present in organic matter. Carbon-14 has a half-life of 5,730 years, meaning that after 5,730 years, half of the carbon-14 will decay into another chemical, in this case, nitrogen-14. Every 5,730 years, another half will decay and so on. By determining the amount of carbon-14 present relative to the amount of nitrogen-14, scientists can determine the age of whatever it is that is being analyzed. While carbon-14 is a reliable method for determining the age of organic matter, it will not work for determining things that are billions of years old. 

To find out when the sun first began to form, astronomers look for iron-60, a rare isotope of iron that is only produced during a supernova explosion. A supernova likely preceded the formation of our solar system, and the energy released from the explosion likely ignited the formation of the sun billions of years ago. Iron-60 has a half-life of 2.26-million years, wherein it decays into nickel-60. Like with carbon-14 and nitrogen-14, astronomers analyze rocks from asteroids and meteors to determine the ratio between iron-60 and nickel-60, which produces an age of around 4.6-billion years. Furthermore, other dating methods used on Earth and the moon have produced ages of around 4.5-billion years, offering further evidence that the sun is at least that old.

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Lifespan Of The Sun

The Sun

The sun is 4.6-billion years old, and astronomers believe that it is only about halfway through its life. We obviously cannot see into the future, and so how do scientists estimate the amount of time the sun will exist for? The process is actually rather simple, and it involves knowing how much fuel the sun has and rate at which it consumes that fuel. Like every other star in the universe, the sun is powered by the nuclear fusion of hydrogen nuclei in its core. When hydrogen is fused together, it produces helium and vast amounts of energy that power the star. So long as nuclear fusion is maintained within the core, the sun will remain a main sequence star. However, that fuel will eventually run out, and when it does, the sun will enter into the final stages of life. By knowing the amount of fuel the sun has and the rate at which it uses that fuel, astronomers estimate that the sun will continue fusing hydrogen in its core for at least another 4 to 5-billion years. When the sun does begin to run out of usable hydrogen, it will evolve into a red giant, eventually blowing off its outer layers. Those outer layers will form a shell of stellar material called a planetary nebula. Meanwhile, the core of the sun will collapse and become a white dwarf. 

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UBC Okanagan study to investigate where Eurasian watermilfoil occurs in lakes – Vernon Morning Star

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A UBC Okanagan pilot project is seeking to better pinpoint and map where the beginnings of Eurasian watermilfoil (EWM) infestation occurs in the large lakes within the Okanagan Valley watershed.

If this pilot project proves successful, it could become a blueprint for other jurisdictions to follow in their own battles with this aquatic plant or other invasive aquatic species, says UBCO assistant professor Mathieu Bourbonnais.

Bourbonnais, with the Irving K. Barber Faculty of Science, is overseeing the project with the assistance of masters graduate student Mackenzie Clarke.

The data modelling prototype is using the technology of topobathymetric lidar, the science of simultaneously measuring and recording three distinct surfaces – land, water and submerged land up to 20 metres below the water surface – using airborne laser-based infrared imagery sensors.

Bourbonnais says being able to better identify potential or small milfoil patches will give better control management tools for the Okanagan Basin Water Board’s Euroasian watermilfoil harvest program, which currently is about an $800,000 a year initiative to try and control the growth and limit the damage of the invasive water plant.

It could also potentially target specific watermilfoil growth sites before they grow out of control near valley lake areas deemed sensitive by Environment Canada for the preservation of the Rocky Mountain Ridge Mussels.

He said EWM has been a formidable invasive aquatic plant species to control since it was introduced into the Okanagan Valley lake system some 40 years ago.

It has also illustrated to the water board the need to be stringent when trying to avoid the Zebra and Quagga mussels from being introduced into the lake system.

Like watermilfoil, there is no solution for removing the mussels once they are introduced into a lake system. It is a rooted submerged plant inhabiting the shallows waters of lakes across North America.

EWM originated from Asia, Europe and Northern Africa and has spread rapidly, introduced in North America from the ballast water of ships or aquarium activities.

Bourbonnais said a lake choked with watermilfoil growth impacts the biodiversity and food webs reliant on the lake habitat, alter the water temperature and impacts its recreational use for swimmers and boaters.

“The impact of invasive species on our lake aquatic systems costs billions of dollars to deal with across the country. It definitely has an impact both ecologically and economically,” he said.

The pilot project fieldwork will be done by early spring, he said, with the hope it provides data upon which to target areas for harvesting leading up to the permit application process next year.

“The goal is the Okanagan Basin Water Board can take the data generated from this research model and liaise with the province and federal government on how to go forward,” he said.

“We hope it can help the management strategy of where to send the lake rototillers to pull up the plants.”

READ MORE: Milfoil infestation continues to plague Okanagan watershed

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