Is there life below the Martian surface?

This beautiful composite consists of 1,000 images acquired during the Viking missions to Mars in the late 1970s. Read more about this image.

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Galactic cosmic rays that penetrate the Martian surface can potentially trigger the kind of chemical reactions that biological life can harness for metabolism. That’s according to a new study published July 28, 2020 in Scientific Reports, an online peer-reviewed journal published by Nature. Researcher Dimitra Atri – of New York University Abu Dhabi in the United Arab Emirates – is lead author of the new study, which peers (theoretically) below the Martian surface to see how likely it is for life to survive. He said:

It is exciting to contemplate that life could survive in such a harsh environment, as few as 2 meters [6 feet] below the surface of Mars.

Of all the planets in our solar system, Mars is most similar to Earth. Some of the streaks on Mars’ surface may have been caused by running water in the distant past. Volcanoes once exploded there. Even today, the ice caps that sit atop Mars’ poles have some similarities with our own planet’s polar regions. And the seasons change on the red planet in ways reminiscent of earthly seasons. Because it’s so reminiscent of Earth – and because the idea of humans on Mars has long been a dream of both science fiction writers and space engineers – Mars has been the most investigated planet in our solar system. That is particularly true with respect to the search for extraterrestrial life.

But, to date, no one has discovered life on Mars, in any form. The harsh conditions on its surface may prevent life from existing there. But the subsurface of Mars might be a different story. From Dimitra Atri’s new paper:

There is growing evidence suggesting the presence of aqueous environment on ancient Mars, raising the question of the possibility of life in such an environment. Subsequently, with the erosion of the Martian atmosphere resulting in drastic changes in its climate, surface water disappeared, shrinking habitable spaces on the planet, with only a limited amount of water remaining near the surface in form of brines and water-ice deposits. Life, if it ever existed, would have had to adapt to harsh modern conditions, which includes low temperatures and surface pressure, and high radiation dose.

Rovers have been crawling Mars’ surface, and orbiters have been peering down at Mars, for decades. Meanwhile, Mars’ subsurface environment has barely begun to be explored. According to scientists, below its surface, Mars is less harsh and has traces of water in form of water-ice and brines. The new study considers the galactic cosmic rays – high energy particles that emerge from the remnants of violent explosions, such as supernovae – that constantly bombard and penetrate the Martian surface. The study suggests that galactic cosmic rays might serve as energy to trigger the kind of reactions that lead to organic chemicals, the sorts of chemicals upon which all life is based.

Traveling at nearly the speed of light, galactic cosmic rays enter our solar system from outer space. They’re able to penetrate a few meters below the Martian surface. This radiation might make this region hospitable for potential life to evolve, Atri suggests.

Scientists believe that Mars was once warmer and more suitable to life than it is now. Could life (if it ever existed) have survived the planet’s subsequent climate change? From the paper:

… if life did exist on ancient Mars, there is a possibility of survival, which can be estimated based on our knowledge of extremophiles that are known to survive in comparably harsh environments on Earth. Such microbial life could have either originated on Mars, or been transported from elsewhere, including from the Earth.

This possibility of Martian subsurface life will be explored for the first time in 2022 by the Rosalind Franklin rover, which is part of the European Space Agency’s and Roscosmos’ ExoMars mission. Like so many Mars missions before it, the rover’s goal will be to establish whether life currently exists or has ever existed on the red planet. From the website:

Determining whether life ever existed on the red planet, or still does today, is at the heart of the ExoMars program. While spacecraft exploring Mars in the last decades have shown that the surface is dry and barren, billions of years ago it was much more reminiscent of Earth, with water flowing in rivers and lakes, perhaps seas. If life ever began in this very early period, scientists think that the best chances to find evidence for it is to look underground, in ancient regions of Mars that were once influenced by water.

To do this, the rover is equipped with a drill that can collect samples up to two meters (about six feet) below Mars’ surface.

The Rosalind Franklin rover is scheduled to be launched in 2022.

Bottom line: A new study theorizes that galactic cosmic rays might serve as energy that can be harnessed by subsurface Martian life for metabolism. This possibility will be explored in depth by the Rosalind Franklin rover which will be launched in 2022.

Source: Investigating the biological potential of galactic cosmic ray-induced radiation-driven chemical disequilibrium in the Martian subsurface environment

Via NYU Abu Dhabi

from EarthSky https://ift.tt/33nap1c

This beautiful composite consists of 1,000 images acquired during the Viking missions to Mars in the late 1970s. Read more about this image.

EarthSky’s yearly crowd-funding campaign is in progress. In 2020, we are donating 8.5% to No Kids Hungry. Please donate to help us keep going, and help feed a kid!

Galactic cosmic rays that penetrate the Martian surface can potentially trigger the kind of chemical reactions that biological life can harness for metabolism. That’s according to a new study published July 28, 2020 in Scientific Reports, an online peer-reviewed journal published by Nature. Researcher Dimitra Atri – of New York University Abu Dhabi in the United Arab Emirates – is lead author of the new study, which peers (theoretically) below the Martian surface to see how likely it is for life to survive. He said:

It is exciting to contemplate that life could survive in such a harsh environment, as few as 2 meters [6 feet] below the surface of Mars.

Of all the planets in our solar system, Mars is most similar to Earth. Some of the streaks on Mars’ surface may have been caused by running water in the distant past. Volcanoes once exploded there. Even today, the ice caps that sit atop Mars’ poles have some similarities with our own planet’s polar regions. And the seasons change on the red planet in ways reminiscent of earthly seasons. Because it’s so reminiscent of Earth – and because the idea of humans on Mars has long been a dream of both science fiction writers and space engineers – Mars has been the most investigated planet in our solar system. That is particularly true with respect to the search for extraterrestrial life.

But, to date, no one has discovered life on Mars, in any form. The harsh conditions on its surface may prevent life from existing there. But the subsurface of Mars might be a different story. From Dimitra Atri’s new paper:

There is growing evidence suggesting the presence of aqueous environment on ancient Mars, raising the question of the possibility of life in such an environment. Subsequently, with the erosion of the Martian atmosphere resulting in drastic changes in its climate, surface water disappeared, shrinking habitable spaces on the planet, with only a limited amount of water remaining near the surface in form of brines and water-ice deposits. Life, if it ever existed, would have had to adapt to harsh modern conditions, which includes low temperatures and surface pressure, and high radiation dose.

Rovers have been crawling Mars’ surface, and orbiters have been peering down at Mars, for decades. Meanwhile, Mars’ subsurface environment has barely begun to be explored. According to scientists, below its surface, Mars is less harsh and has traces of water in form of water-ice and brines. The new study considers the galactic cosmic rays – high energy particles that emerge from the remnants of violent explosions, such as supernovae – that constantly bombard and penetrate the Martian surface. The study suggests that galactic cosmic rays might serve as energy to trigger the kind of reactions that lead to organic chemicals, the sorts of chemicals upon which all life is based.

Traveling at nearly the speed of light, galactic cosmic rays enter our solar system from outer space. They’re able to penetrate a few meters below the Martian surface. This radiation might make this region hospitable for potential life to evolve, Atri suggests.

Scientists believe that Mars was once warmer and more suitable to life than it is now. Could life (if it ever existed) have survived the planet’s subsequent climate change? From the paper:

… if life did exist on ancient Mars, there is a possibility of survival, which can be estimated based on our knowledge of extremophiles that are known to survive in comparably harsh environments on Earth. Such microbial life could have either originated on Mars, or been transported from elsewhere, including from the Earth.

This possibility of Martian subsurface life will be explored for the first time in 2022 by the Rosalind Franklin rover, which is part of the European Space Agency’s and Roscosmos’ ExoMars mission. Like so many Mars missions before it, the rover’s goal will be to establish whether life currently exists or has ever existed on the red planet. From the website:

Determining whether life ever existed on the red planet, or still does today, is at the heart of the ExoMars program. While spacecraft exploring Mars in the last decades have shown that the surface is dry and barren, billions of years ago it was much more reminiscent of Earth, with water flowing in rivers and lakes, perhaps seas. If life ever began in this very early period, scientists think that the best chances to find evidence for it is to look underground, in ancient regions of Mars that were once influenced by water.

To do this, the rover is equipped with a drill that can collect samples up to two meters (about six feet) below Mars’ surface.

The Rosalind Franklin rover is scheduled to be launched in 2022.

Bottom line: A new study theorizes that galactic cosmic rays might serve as energy that can be harnessed by subsurface Martian life for metabolism. This possibility will be explored in depth by the Rosalind Franklin rover which will be launched in 2022.

Source: Investigating the biological potential of galactic cosmic ray-induced radiation-driven chemical disequilibrium in the Martian subsurface environment

Via NYU Abu Dhabi

from EarthSky https://ift.tt/33nap1c

Can other gases help explain Mars methane mystery?

Artist’s illustration of the joint European-Russian Trace Gas Orbiter (TGO), which has been orbiting Mars since 2016. Image via ESA/ ATG medialab/ Space.com.

EarthSky’s yearly crowd-funding campaign is in progress. In 2020, we are donating 8.5% of all incoming revenues to No Kids Hungry. Click to learn more and donate.

Is the methane in Mars’ atmosphere geological in origin, arising from processes in the Martian rocks? Or could it be a sign of life? Mars methane has been detected by telescopes on Earth, orbiting spacecraft and even the Curiosity rover on Mars. Meanwhile, European Space Agency (ESA) scientists have been frustrated by the lack of detection of methane by their Trace Gas Orbiter (TGO) – part of the ExoMars mission – designed in part specifically to measure methane. The orbiter has been circling Mars since 2016, but, so far, no methane. Now scientists think they have an answer.

The new findings come from scientists in the U.K. and Russia. They might help to explain why TGO hasn’t detected methane on Mars, ESA has reported. The answer has to do with two other gases in the atmosphere, carbon dioxide (CO2) and ozone (O3).

Researchers published two new peer-reviewed papers on July 27, 2020, in Astronomy & Astrophysics. One deals with the carbon dioxide detection and the other with the ozone.

While TGO still hasn’t directly detected methane, it did make another intriguing discovery that might explain why. It detected both carbon dioxide and ozone in the regions where methane had been expected to be seen. Both gases have been known about for a long time, and Mars’ atmosphere is mostly carbon dioxide, so why is this surprising?

Spectral signatures of carbon dioxide (left) and ozone (right) on Mars, as detected by the ACS instrument on the Trace Gas Orbiter (TGO). Image via Olsen et al./ ESA.

Kevin Olsen of the University of Oxford, who led the U.K. study, explained in a statement:

These features are both puzzling and surprising.

They lie over the exact wavelength range where we expected to see the strongest signs of methane. Before this discovery, the CO2 feature was completely unknown, and this is the first time ozone on Mars has been identified in this part of the infrared wavelength range.

TGO made the observations after studying the Martian atmosphere for a full Martian year, using its Atmospheric Chemistry Suite (ACS). ACS is extremely sensitive, and can show scientists how these gases interact with light. The researchers were not expecting to see ozone in the part of the infrared wavelength range where methane was expected to be seen. Previous observations relied upon seeing the ozone signature in the ultraviolet, a technique which only allowed measurement at high altitudes (over 20 km [12 miles] above the surface). ACS, however, can map ozone down at lower altitudes as well. From the ozone paper:

We report the first observation of the spectral features of Martian ozone (O3) in the mid-infrared range using the Atmospheric Chemistry Suite Mid-InfaRed (MIR) channel, a cross-dispersion spectrometer operating in solar occultation mode with the finest spectral resolution of any remote sensing mission to Mars.

The ability to simultaneously resolve these species has an impact on current and past attempts to measure the abundance of methane in the atmosphere of Mars.

In this region and time period, corresponding to the northern autumn equinox, we were able to observe significant amounts of ozone in the mid-infrared at altitudes below 30 km [19 miles].

Ozone absorption below 30 km in the mid-infrared range has important implications for searches for atmospheric methane. Past observations of methane in the atmosphere of Mars (Formisano et al. 2004; Krasnopolsky et al. 2004; Mumma et al. 2009; Webster et al. 2015) were a driving cause of the development of the ExoMars TGO mission. CH4 should have a relatively short lifetime in the atmosphere of Mars (several hundred years), meaning current observations require an active source (Lefèvre & Forget 2009). A key objective of the TGO mission is to determine with certainty whether or not CH4 is present in the atmosphere of Mars and what its spatial and temporal variability is, and to localize any possible sources. This story continues to be intriguing as the first results from TGO reported an upper limit on the order of 50 pptv (Korablev et al. 2019), and ACS MIR observations continue to reveal no methane after one MY. In its place, we have instead found the rare and previously undetected signatures of O3 and a new CO2 magnetic dipole band (Trokhimovskiy et al. 2020).

Another graph highlighting the unexpected carbon dioxide signature – a magnetic dipole absorption band of the molecule – as detected by the ACS instrument on the Trace Gas Orbiter (TGO). Image via Trokhimovskiy et al./ ESA.

ACS also saw carbon dioxide at the infrared wavelength range where they expected to see methane, which was also unexpected. Alexander Trokhimovsky of the Space Research Institute of the Russian Academy of Sciences in Moscow, who led the Russian study, said:

Discovering an unforeseen CO2 signature where we hunt for methane is significant. This signature could not be accounted for before, and may therefore have played a role in detections of small amounts of methane at Mars.

As noted by Meghan Bartels in an article for Space.com, the odd alignment of these two gases where methane had been expected suggests that they are interfering with the detection of methane by TGO. From the ozone paper:

The observed spectral signature of ozone at 3000–3060 cm -1 directly overlaps with the spectral range of the methane (CH4) v3 vibration-rotation band, and it, along with a newly discovered CO2 band in the same region, may interfere with measurements of methane abundance.

Comparison of the atmospheres of Mars and Earth. Image via ESA.

A history of key methane measurements on Mars from 1999 to 2018. Image via ESA.

These findings do not directly disagree with those of other missions, since the observations were mostly done at different times from those that did find methane, and TGO is designed to sniff out very tiny amounts of methane, not larger plumes as seen before (although even those plumes are very small compared to methane plumes on Earth). Olsen said:

In fact, we’re actively working on coordinating measurements with other missions. Rather than disputing any previous claims, this finding is a motivator for all teams to look closer; the more we know, the more deeply and accurately we can explore Mars’ atmosphere.

The researchers wondered if previous observations from Earth, Mars Express (using the Planetary Fourier Spectrometer, or PFS) or Curiosity (using the Tunable Laser Spectrometer, or TLS), could have mistaken carbon dioxide and/or ozone for some of the methane measurements, but that is considered to be unlikely. From the ozone paper:

CO2 and O3 alone cannot account for the detections made by both teams. In the case of PFS, the previously unknown CO2 features would impact all observations equally, as CO2 is always present and well-mixed. The PFS team has instead identified CH4 in only a small number of observations (Formisano et al. 2004; Giuranna et al. 2019). Furthermore, we computed spectra with O3 at two and three times the quantities in our observations, and the sheer magnitude of CH4 observed by these latter authors (15 ppbv) is far too large to be easily mistaken for O3.

In the case of TLS, which takes measurements of CH4 at the surface and mostly at night where and when the O3 abundance is greatest, again, it is unlikely that the large quantity of CH4 observed (up to 9 ppbv) resulted from O3, yet the latter may interfere in the measurement of the background level of methane in the so-called enriched mode as both ozone and methane should sustain the same enrichment.

For ground-based observations, strong O3 absorption features from Earth’s atmosphere must first be removed before retrieving mixing ratios for Mars (Krasnopolsky 2012; Mumma et al. 2009); O3 must be accounted for, although this step makes the retrieval more difficult (Zahnle et al. 2011). Finally, in the case of all previous observations, the rapid evolution and disappearance of CH4 are still not explained, although ozone chemistry is very rapid, with a lifetime on the order of days.

The possible methods by which scientists think methane can be created and destroyed on Mars. Image via ESA.

The results will not only help scientists to better track down methane, but also learn more about the Martian atmosphere overall. Alexander said:

These findings enable us to build a fuller understanding of our planetary neighbor.

Ozone and CO2 are important in Mars’ atmosphere. By not accounting for these gases properly, we run the risk of mischaracterizing the phenomena or properties we see.

Together, these two studies take a significant step toward revealing the true characteristics of Mars: toward a new level of accuracy and understanding.

TGO’s primary mission is to detect trace gases that could originate from either geological or biological processes. The ExoMars mission overall is a joint effort between Europe and Russia. According to TGO Project Scientist Håkan Svedhem:

These findings are the direct result of hugely successful and ongoing collaboration between European and Russian scientists as part of ExoMars.

They set new standards for future spectral observations, and will help us to paint a more complete picture of Mars’ atmospheric properties – including where and when there may be methane to be found, which remains a key question in Mars exploration.

Additionally, these findings will prompt a thorough analysis of all the relevant data we’ve collected to date – and the prospect of new discovery in this way is, as always, very exciting. Each piece of information revealed by the ExoMars Trace Gas Orbiter marks progress towards a more accurate understanding of Mars, and puts us one step closer to unravelling the planet’s lingering mysteries.

Kevin Olsen of the University of Oxford in the UK, who led the Mars ozone study. Image via University of Oxford.

We still don’t know the origin of Martian methane, but the new studies from Europe and Russia of other gases in the atmosphere will help to refine and narrow down the possibilities.

Bottom line: ESA’s TGO orbiter has unexpectedly detected carbon dioxide and ozone in Mars’ atmosphere where the elusive methane should be.

Source: First observation of the magnetic dipole CO2 absorption band at 3.3 um in the atmosphere of Mars by the ExoMars Trace Gas Orbiter ACS instrument

Source: First detection of ozone in the mid-infrared at Mars: implications for methane detection

Via ESA

from EarthSky https://ift.tt/2BRRqjN

Artist’s illustration of the joint European-Russian Trace Gas Orbiter (TGO), which has been orbiting Mars since 2016. Image via ESA/ ATG medialab/ Space.com.

EarthSky’s yearly crowd-funding campaign is in progress. In 2020, we are donating 8.5% of all incoming revenues to No Kids Hungry. Click to learn more and donate.

Is the methane in Mars’ atmosphere geological in origin, arising from processes in the Martian rocks? Or could it be a sign of life? Mars methane has been detected by telescopes on Earth, orbiting spacecraft and even the Curiosity rover on Mars. Meanwhile, European Space Agency (ESA) scientists have been frustrated by the lack of detection of methane by their Trace Gas Orbiter (TGO) – part of the ExoMars mission – designed in part specifically to measure methane. The orbiter has been circling Mars since 2016, but, so far, no methane. Now scientists think they have an answer.

The new findings come from scientists in the U.K. and Russia. They might help to explain why TGO hasn’t detected methane on Mars, ESA has reported. The answer has to do with two other gases in the atmosphere, carbon dioxide (CO2) and ozone (O3).

Researchers published two new peer-reviewed papers on July 27, 2020, in Astronomy & Astrophysics. One deals with the carbon dioxide detection and the other with the ozone.

While TGO still hasn’t directly detected methane, it did make another intriguing discovery that might explain why. It detected both carbon dioxide and ozone in the regions where methane had been expected to be seen. Both gases have been known about for a long time, and Mars’ atmosphere is mostly carbon dioxide, so why is this surprising?

Spectral signatures of carbon dioxide (left) and ozone (right) on Mars, as detected by the ACS instrument on the Trace Gas Orbiter (TGO). Image via Olsen et al./ ESA.

Kevin Olsen of the University of Oxford, who led the U.K. study, explained in a statement:

These features are both puzzling and surprising.

They lie over the exact wavelength range where we expected to see the strongest signs of methane. Before this discovery, the CO2 feature was completely unknown, and this is the first time ozone on Mars has been identified in this part of the infrared wavelength range.

TGO made the observations after studying the Martian atmosphere for a full Martian year, using its Atmospheric Chemistry Suite (ACS). ACS is extremely sensitive, and can show scientists how these gases interact with light. The researchers were not expecting to see ozone in the part of the infrared wavelength range where methane was expected to be seen. Previous observations relied upon seeing the ozone signature in the ultraviolet, a technique which only allowed measurement at high altitudes (over 20 km [12 miles] above the surface). ACS, however, can map ozone down at lower altitudes as well. From the ozone paper:

We report the first observation of the spectral features of Martian ozone (O3) in the mid-infrared range using the Atmospheric Chemistry Suite Mid-InfaRed (MIR) channel, a cross-dispersion spectrometer operating in solar occultation mode with the finest spectral resolution of any remote sensing mission to Mars.

The ability to simultaneously resolve these species has an impact on current and past attempts to measure the abundance of methane in the atmosphere of Mars.

In this region and time period, corresponding to the northern autumn equinox, we were able to observe significant amounts of ozone in the mid-infrared at altitudes below 30 km [19 miles].

Ozone absorption below 30 km in the mid-infrared range has important implications for searches for atmospheric methane. Past observations of methane in the atmosphere of Mars (Formisano et al. 2004; Krasnopolsky et al. 2004; Mumma et al. 2009; Webster et al. 2015) were a driving cause of the development of the ExoMars TGO mission. CH4 should have a relatively short lifetime in the atmosphere of Mars (several hundred years), meaning current observations require an active source (Lefèvre & Forget 2009). A key objective of the TGO mission is to determine with certainty whether or not CH4 is present in the atmosphere of Mars and what its spatial and temporal variability is, and to localize any possible sources. This story continues to be intriguing as the first results from TGO reported an upper limit on the order of 50 pptv (Korablev et al. 2019), and ACS MIR observations continue to reveal no methane after one MY. In its place, we have instead found the rare and previously undetected signatures of O3 and a new CO2 magnetic dipole band (Trokhimovskiy et al. 2020).

Another graph highlighting the unexpected carbon dioxide signature – a magnetic dipole absorption band of the molecule – as detected by the ACS instrument on the Trace Gas Orbiter (TGO). Image via Trokhimovskiy et al./ ESA.

ACS also saw carbon dioxide at the infrared wavelength range where they expected to see methane, which was also unexpected. Alexander Trokhimovsky of the Space Research Institute of the Russian Academy of Sciences in Moscow, who led the Russian study, said:

Discovering an unforeseen CO2 signature where we hunt for methane is significant. This signature could not be accounted for before, and may therefore have played a role in detections of small amounts of methane at Mars.

As noted by Meghan Bartels in an article for Space.com, the odd alignment of these two gases where methane had been expected suggests that they are interfering with the detection of methane by TGO. From the ozone paper:

The observed spectral signature of ozone at 3000–3060 cm -1 directly overlaps with the spectral range of the methane (CH4) v3 vibration-rotation band, and it, along with a newly discovered CO2 band in the same region, may interfere with measurements of methane abundance.

Comparison of the atmospheres of Mars and Earth. Image via ESA.

A history of key methane measurements on Mars from 1999 to 2018. Image via ESA.

These findings do not directly disagree with those of other missions, since the observations were mostly done at different times from those that did find methane, and TGO is designed to sniff out very tiny amounts of methane, not larger plumes as seen before (although even those plumes are very small compared to methane plumes on Earth). Olsen said:

In fact, we’re actively working on coordinating measurements with other missions. Rather than disputing any previous claims, this finding is a motivator for all teams to look closer; the more we know, the more deeply and accurately we can explore Mars’ atmosphere.

The researchers wondered if previous observations from Earth, Mars Express (using the Planetary Fourier Spectrometer, or PFS) or Curiosity (using the Tunable Laser Spectrometer, or TLS), could have mistaken carbon dioxide and/or ozone for some of the methane measurements, but that is considered to be unlikely. From the ozone paper:

CO2 and O3 alone cannot account for the detections made by both teams. In the case of PFS, the previously unknown CO2 features would impact all observations equally, as CO2 is always present and well-mixed. The PFS team has instead identified CH4 in only a small number of observations (Formisano et al. 2004; Giuranna et al. 2019). Furthermore, we computed spectra with O3 at two and three times the quantities in our observations, and the sheer magnitude of CH4 observed by these latter authors (15 ppbv) is far too large to be easily mistaken for O3.

In the case of TLS, which takes measurements of CH4 at the surface and mostly at night where and when the O3 abundance is greatest, again, it is unlikely that the large quantity of CH4 observed (up to 9 ppbv) resulted from O3, yet the latter may interfere in the measurement of the background level of methane in the so-called enriched mode as both ozone and methane should sustain the same enrichment.

For ground-based observations, strong O3 absorption features from Earth’s atmosphere must first be removed before retrieving mixing ratios for Mars (Krasnopolsky 2012; Mumma et al. 2009); O3 must be accounted for, although this step makes the retrieval more difficult (Zahnle et al. 2011). Finally, in the case of all previous observations, the rapid evolution and disappearance of CH4 are still not explained, although ozone chemistry is very rapid, with a lifetime on the order of days.

The possible methods by which scientists think methane can be created and destroyed on Mars. Image via ESA.

The results will not only help scientists to better track down methane, but also learn more about the Martian atmosphere overall. Alexander said:

These findings enable us to build a fuller understanding of our planetary neighbor.

Ozone and CO2 are important in Mars’ atmosphere. By not accounting for these gases properly, we run the risk of mischaracterizing the phenomena or properties we see.

Together, these two studies take a significant step toward revealing the true characteristics of Mars: toward a new level of accuracy and understanding.

TGO’s primary mission is to detect trace gases that could originate from either geological or biological processes. The ExoMars mission overall is a joint effort between Europe and Russia. According to TGO Project Scientist Håkan Svedhem:

These findings are the direct result of hugely successful and ongoing collaboration between European and Russian scientists as part of ExoMars.

They set new standards for future spectral observations, and will help us to paint a more complete picture of Mars’ atmospheric properties – including where and when there may be methane to be found, which remains a key question in Mars exploration.

Additionally, these findings will prompt a thorough analysis of all the relevant data we’ve collected to date – and the prospect of new discovery in this way is, as always, very exciting. Each piece of information revealed by the ExoMars Trace Gas Orbiter marks progress towards a more accurate understanding of Mars, and puts us one step closer to unravelling the planet’s lingering mysteries.

Kevin Olsen of the University of Oxford in the UK, who led the Mars ozone study. Image via University of Oxford.

We still don’t know the origin of Martian methane, but the new studies from Europe and Russia of other gases in the atmosphere will help to refine and narrow down the possibilities.

Bottom line: ESA’s TGO orbiter has unexpectedly detected carbon dioxide and ozone in Mars’ atmosphere where the elusive methane should be.

Source: First observation of the magnetic dipole CO2 absorption band at 3.3 um in the atmosphere of Mars by the ExoMars Trace Gas Orbiter ACS instrument

Source: First detection of ozone in the mid-infrared at Mars: implications for methane detection

Via ESA

from EarthSky https://ift.tt/2BRRqjN

Mysterious evolution of wonky whale skulls

The skulls of whales with teeth – such as sperm whales (pictured above) – evolved to be lopsided, with the bones on one side in different positions to the same bones on the other side. Image via Day Donaldson/ Flickr/ Science News for Students.

By Ellen Coombs, UCL

Some whales are wonky. You might not know it to look at them, but their skulls are actually incredibly asymmetrical. This mysterious feature helps with echolocation, the way that whales work out where things are by making sounds and sensing how they are reflected back.

But this wonkiness isn’t present in all whales. My colleagues and I recently conducted research to find out why and when wonky whales started to evolve in a different way to their symmetrical cousins. We now know wonky whale skulls first appeared around 30 million years ago, and that they continued to become even more asymmetrical as the creatures evolved into the modern species we know today.

Sperm whale skull. Image via JvL/ Flickr

In order to understand how wonky whales got this way, we needed to look at how they lived and adapted in the past. Fortunately for us, the whale fossil record is so remarkably represented that scientists have even called the whale “a posterchild of evolution”. Complete skulls and skeletons stretch right back to the earliest whales of 50 million years ago, and more fossils are dotted throughout whale history, right up to the living animals we know today.

Asymmetrical narwhal skull – the red arrows highlight the skewed bones. Image via The Conversation.

With this record, we’re able to see that whales’ nostrils have moved from the tip of their snout to the top of their head, an evolutionary tactic to make for easy breathing at the surface of the water. And the skulls of whales with teeth (which technically includes dolphins, as well as species such as sperm whales) have become more lopsided, with the bones on one side in different positions to the same bones on the other side.

This is because of a mass of fatty tissue called a “melon” that toothed whales use for echolocation. The melon and the soft tissue needed for echolocation are positioned leftwards above the skull on toothed whales, giving them a bulbous forehead and also causing the bones in the skull underneath to grow skewed to the left. As toothed whales evolved, their skulls got wonkier.

But why don’t all whales have this wonkiness? The first whales were called “archaeocetes” (which literally means “ancient whales”). They evolved from walking on land to being fully aquatic in a relatively short 8 million years or so.

We know that archaeocete fossils have wonky rostrums (or snouts). This might be a distortion of the fossils or a feature that helped archaeocetes work out which direction sounds were coming from underwater.

Ambulocetus natans, an early whale ancestor. Image via Ghedoghedo

Then, around 39 million years ago, whales diverged into two groups: those with teeth in their mouths, known as the “odontocetes, and those with baleen (rows of bristles that allow whales to filter food from the water), known as the “mysticetes”.

At some point, the toothed whales evolved wonky skulls and echolocation. However, the mysticetes, which include the big baleen whales (such as blue whales), diverged down a completely different evolutionary path. They evolved baleen and filter feeding and skulls that are more symmetrical than both the archaeocetes and the toothed whales.

We wanted to understand why, and exactly when, this happened. So to track asymmetry in the evolution of the whale skull, we produced 3D scans of 162 skulls, 78 of which were fossils. By mapping this wonky shape change in the skull across the whale family tree, we could track precisely when in evolutionary history it first appeared and in which families it evolved.

Asymmetry appears

Based on analyses of these skulls, naso-facial asymmetry (wonkiness) appears to have first evolved around 30 million years ago. This was after the transition from archaeocetes to modern whales, and after the split between the odontocetes and the mysticetes. Around the same time this wonkiness was appearing, these early toothed whales were evolving high-frequency hearing and complex echolocation.

We also confirmed that early ancestors of living whales had little cranial asymmetry in the naso-facial area and likely were not able to echolocate. As such, it’s likely that baleen whales have never been able to echolocate.

Most surprisingly, this asymmetry has reached its highest levels in some specific animals such a sperm whales and narwhals and other species that live in deep or extreme environments.

This suggests that animals living in these complex environments, including belugas that live in icy, cluttered waters and river dolphins that live in shallow, murky rivers, have evolved a different echolocation ability such as a more diverse or discrete sound repertoire to help them navigate and hunt, and with it the bones around the nasal and face have become more asymmetrical.

This evolutionary path of toothed whales becoming ever more asymmetrical suggests that their skulls and the overlying soft tissues may continue to get wonkier as their echolocation techniques become more specialized.

These findings remind us not only of the complex evolutionary pathways that cetaceans have undergone to become the superbly adapted iconic ocean inhabitants that we know today, but also that despite living alongside some of the largest animals that have ever existed, there is still a lot for us to learn about them.

Ellen Coombs, PhD Candidate in Biosciences, UCL

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bottom line: Why and when some whales evolved asymmetrical skulls

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The skulls of whales with teeth – such as sperm whales (pictured above) – evolved to be lopsided, with the bones on one side in different positions to the same bones on the other side. Image via Day Donaldson/ Flickr/ Science News for Students.

By Ellen Coombs, UCL

Some whales are wonky. You might not know it to look at them, but their skulls are actually incredibly asymmetrical. This mysterious feature helps with echolocation, the way that whales work out where things are by making sounds and sensing how they are reflected back.

But this wonkiness isn’t present in all whales. My colleagues and I recently conducted research to find out why and when wonky whales started to evolve in a different way to their symmetrical cousins. We now know wonky whale skulls first appeared around 30 million years ago, and that they continued to become even more asymmetrical as the creatures evolved into the modern species we know today.

Sperm whale skull. Image via JvL/ Flickr

In order to understand how wonky whales got this way, we needed to look at how they lived and adapted in the past. Fortunately for us, the whale fossil record is so remarkably represented that scientists have even called the whale “a posterchild of evolution”. Complete skulls and skeletons stretch right back to the earliest whales of 50 million years ago, and more fossils are dotted throughout whale history, right up to the living animals we know today.

Asymmetrical narwhal skull – the red arrows highlight the skewed bones. Image via The Conversation.

With this record, we’re able to see that whales’ nostrils have moved from the tip of their snout to the top of their head, an evolutionary tactic to make for easy breathing at the surface of the water. And the skulls of whales with teeth (which technically includes dolphins, as well as species such as sperm whales) have become more lopsided, with the bones on one side in different positions to the same bones on the other side.

This is because of a mass of fatty tissue called a “melon” that toothed whales use for echolocation. The melon and the soft tissue needed for echolocation are positioned leftwards above the skull on toothed whales, giving them a bulbous forehead and also causing the bones in the skull underneath to grow skewed to the left. As toothed whales evolved, their skulls got wonkier.

But why don’t all whales have this wonkiness? The first whales were called “archaeocetes” (which literally means “ancient whales”). They evolved from walking on land to being fully aquatic in a relatively short 8 million years or so.

We know that archaeocete fossils have wonky rostrums (or snouts). This might be a distortion of the fossils or a feature that helped archaeocetes work out which direction sounds were coming from underwater.

Ambulocetus natans, an early whale ancestor. Image via Ghedoghedo

Then, around 39 million years ago, whales diverged into two groups: those with teeth in their mouths, known as the “odontocetes, and those with baleen (rows of bristles that allow whales to filter food from the water), known as the “mysticetes”.

At some point, the toothed whales evolved wonky skulls and echolocation. However, the mysticetes, which include the big baleen whales (such as blue whales), diverged down a completely different evolutionary path. They evolved baleen and filter feeding and skulls that are more symmetrical than both the archaeocetes and the toothed whales.

We wanted to understand why, and exactly when, this happened. So to track asymmetry in the evolution of the whale skull, we produced 3D scans of 162 skulls, 78 of which were fossils. By mapping this wonky shape change in the skull across the whale family tree, we could track precisely when in evolutionary history it first appeared and in which families it evolved.

Asymmetry appears

Based on analyses of these skulls, naso-facial asymmetry (wonkiness) appears to have first evolved around 30 million years ago. This was after the transition from archaeocetes to modern whales, and after the split between the odontocetes and the mysticetes. Around the same time this wonkiness was appearing, these early toothed whales were evolving high-frequency hearing and complex echolocation.

We also confirmed that early ancestors of living whales had little cranial asymmetry in the naso-facial area and likely were not able to echolocate. As such, it’s likely that baleen whales have never been able to echolocate.

Most surprisingly, this asymmetry has reached its highest levels in some specific animals such a sperm whales and narwhals and other species that live in deep or extreme environments.

This suggests that animals living in these complex environments, including belugas that live in icy, cluttered waters and river dolphins that live in shallow, murky rivers, have evolved a different echolocation ability such as a more diverse or discrete sound repertoire to help them navigate and hunt, and with it the bones around the nasal and face have become more asymmetrical.

This evolutionary path of toothed whales becoming ever more asymmetrical suggests that their skulls and the overlying soft tissues may continue to get wonkier as their echolocation techniques become more specialized.

These findings remind us not only of the complex evolutionary pathways that cetaceans have undergone to become the superbly adapted iconic ocean inhabitants that we know today, but also that despite living alongside some of the largest animals that have ever existed, there is still a lot for us to learn about them.

Ellen Coombs, PhD Candidate in Biosciences, UCL

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bottom line: Why and when some whales evolved asymmetrical skulls

from EarthSky https://ift.tt/2EO6lgh

How to watch SpaceX Crew Dragon splashdown today

The two-man SpaceX Crew Dragon will splash down in the Gulf of Mexico on Sunday, August 2, 2020, completing its two-month demo mission to the International Space Station and back. The crew is expected to splash down at 18:48 UTC (2:48 p.m. ET; translate UTC to your time), with the target landing area the Gulf of Mexico off the coast of Pensacola, Florida. It’ll be the first splashdown in 45 years, following the joint U.S.-Soviet Apollo-Soyuz mission in 1975. NASA TV is hosting a livestream of the return of astronauts Robert Behnken and Douglas Hurley from their 63 days in space (about 1,024 orbits around Earth). When we clicked in to NASA TV this morning, they were already discussing the splashdown. Official coverage of the event on NASA TV began at about 11:25 UTC (7:25 a.m. ET).

Watch the splashdown on the video above, or go to NASA TV.

The crew had been originally intended to splashdown in the Atlantic, but the location was changed due to Hurricane Isaias’ pending arrival on the east coast of Florida.

Behnken and Hurley have been in space since May 30, when they launched at the helm of the first crewed U.S. mission to orbit on a private spacecraft, part of a Space X-NASA partnership.

In this image from video made available by NASA, astronauts Doug Hurley, left, and Bob Behnken prepare for undocking from the International Space Station, aboard the SpaceX Crew Dragon capsule on Saturday, August 1, 2020. Image via NASA/ AP/

Bottom line: How to watch SpaceX Crew Dragon splashdown on Sunday, August 2, 2020

from EarthSky https://ift.tt/33dHHQe

The two-man SpaceX Crew Dragon will splash down in the Gulf of Mexico on Sunday, August 2, 2020, completing its two-month demo mission to the International Space Station and back. The crew is expected to splash down at 18:48 UTC (2:48 p.m. ET; translate UTC to your time), with the target landing area the Gulf of Mexico off the coast of Pensacola, Florida. It’ll be the first splashdown in 45 years, following the joint U.S.-Soviet Apollo-Soyuz mission in 1975. NASA TV is hosting a livestream of the return of astronauts Robert Behnken and Douglas Hurley from their 63 days in space (about 1,024 orbits around Earth). When we clicked in to NASA TV this morning, they were already discussing the splashdown. Official coverage of the event on NASA TV began at about 11:25 UTC (7:25 a.m. ET).

Watch the splashdown on the video above, or go to NASA TV.

The crew had been originally intended to splashdown in the Atlantic, but the location was changed due to Hurricane Isaias’ pending arrival on the east coast of Florida.

Behnken and Hurley have been in space since May 30, when they launched at the helm of the first crewed U.S. mission to orbit on a private spacecraft, part of a Space X-NASA partnership.

In this image from video made available by NASA, astronauts Doug Hurley, left, and Bob Behnken prepare for undocking from the International Space Station, aboard the SpaceX Crew Dragon capsule on Saturday, August 1, 2020. Image via NASA/ AP/

Bottom line: How to watch SpaceX Crew Dragon splashdown on Sunday, August 2, 2020

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Fist-Shaking Moon on August 2 and 3

EarthSky’s yearly crowd-funding campaign is in progress. In 2020, we are donating 8.5% of all incoming revenues to No Kids Hungry. Click to learn more and donate.

We hereby give the August 2 and 3, 2020, full moon a new name: Fist-Shaking Moon. That’s because this full moon is now filling the sky with its light, just as the Perseid meteor shower is rising to its peak on the mornings of August 11, 12 and 13. Yes, the moon will wane in the coming days. But a full moon now means a last quarter moon on August 11. And a last quarter moon is a pretty bright moon, rising at midnight, just as the night’s meteor-watching kicks into full gear. As for us, we’ll be standing outside shaking our fists at this full moon. Will moonlight ruin this year’s Perseids? It’ll surely exert an influence. Here’s how you can optimize your meteor-watching chances this month.

Everyone around the world (except far-northern Arctic latitudes) will see a full-looking moon lighting up the nighttime from about dusk until about dawn on these nights. This bright full moon will be following the planets Jupiter and Saturn westward across the sky throughout the night.

In North America, we also call the August full moon the Sturgeon Moon, Green Corn Moon or Grain Moon. For the Northern Hemisphere, this August full moon ushers in the second of three full moons of the summer season.

In the Southern Hemisphere, where it’s the opposite season, this is second of three winter full moons.

By season, we are referring to the time period between the June solstice and the September equinox.

A lovely shot of the June 10, 2017, moon from Peter Ryan in East Greenwich, Rhode Island.

It’s very hard to tell when a moon is precisely full just by looking at it. This month’s moon turns precisely full on August 3 at 15:59 UTC (translate UTC to your time). At U.S. time zones, that translates to 11:59 a.m. EDT, 10:59 a.m. CDT, 9:59 a.m. MDT, 8:59 a.m. PST, 7:59 a.m. AKDT, and 5:59 a.m. HST. But those times indicate only the crest of the moon’s full phase. They indicate when the moon is most opposite the sun for this month (180 degrees from the sun in ecliptic longitude).

Submit your full moon photo to EarthSky Community Photos

To the eye, on the other hand, the moon appears over 99% illuminated for about a day before and after full moon. People around the world will regard the moon as full on both August 2 and August 3.

Visit Unitarium.com or Heavens-Above.com to know how much of the moon’s face is illuminated in sunlight for right now or any chosen time.

At about the time of the full moon, the moon rises in the east around sunset, climbs highest up for the night around midnight and sets in the west around sunrise. So these next few nights, look for the moon in your eastern sky at dusk and your western sky at dawn.

Want to know the exact time for the full moon at your locality, plus the moonrise and moonset times? Sunrise Sunset Calendars gives the times. Remember to check the Moon phases and Moonrise and moonset boxes.

This August 2020 full moon does not pass through the antisolar point – the point that’s exactly opposite the sun – or else this full moon would undergo a total lunar eclipse. The last time the full moon passed through the antisolar point and through the center of the Earth’s dark umbral shadow was over two years ago, when it staged the longest total lunar eclipse of the 21st century (2001 to 2100) on July 27, 2018.

The July 27, 2018, eclipsed moon rises over the observatories of Instituto Astrofisica de Canarias, in Tenerife. Roberto Porto acquired 200 images to make this star trail composite. See more photos of the July 27, 2018, lunar eclipse.

Last month, in July 2020, the full moon missed the antisolar point and swung south of Earth’s dark umbral shadow. Yet the moon did clip the southern portion of the Earth’s faint penumbral shadow to present a partial penumbral eclipse on July 5, 2020.

The full moon won’t sweep through the Earth’s umbra again until May 26, 2021. But the moon will swing well north of the antisolar point, to display the second-shortest total lunar eclipse of the 21st century (2001 to 2100).

The full moon won’t meet up with the antisolar point until it barely grazes the center of the Earth’s dark shadow during the total lunar eclipse of May 16, 2022.

The worldwide map below shows the day and night sides of Earth at the instant of the August 2020 full moon (August 3, 2020, at 15:59 UTC). The shadow line at left represents sunrise August 3 whereas the shadow line at the right depicts sunset August 3.

You have to be on the nighttime side of Earth to see the moon at the instant it turns full.

The day and night sides of Earth at the instant of full moon (August 3, 2020, at 15:59 UTC). The shadow line at left (running across the Pacific Ocean) depicts sunrise August 3, and the shadow line at right (running across Africa and the Middle east) represents sunset August 3. Worldwide map via EarthView.

Bottom line: On both August 2 and 3, 2020, the brilliant full moon drenches the nighttime with moonlight from dusk until dawn. A full moon now means a last quarter moon – shining in the sky between midnight and dawn – on August 11, one of the peak mornings of this year’s Perseid meteor shower.

from EarthSky https://ift.tt/2YXLxHv

EarthSky’s yearly crowd-funding campaign is in progress. In 2020, we are donating 8.5% of all incoming revenues to No Kids Hungry. Click to learn more and donate.

We hereby give the August 2 and 3, 2020, full moon a new name: Fist-Shaking Moon. That’s because this full moon is now filling the sky with its light, just as the Perseid meteor shower is rising to its peak on the mornings of August 11, 12 and 13. Yes, the moon will wane in the coming days. But a full moon now means a last quarter moon on August 11. And a last quarter moon is a pretty bright moon, rising at midnight, just as the night’s meteor-watching kicks into full gear. As for us, we’ll be standing outside shaking our fists at this full moon. Will moonlight ruin this year’s Perseids? It’ll surely exert an influence. Here’s how you can optimize your meteor-watching chances this month.

Everyone around the world (except far-northern Arctic latitudes) will see a full-looking moon lighting up the nighttime from about dusk until about dawn on these nights. This bright full moon will be following the planets Jupiter and Saturn westward across the sky throughout the night.

In North America, we also call the August full moon the Sturgeon Moon, Green Corn Moon or Grain Moon. For the Northern Hemisphere, this August full moon ushers in the second of three full moons of the summer season.

In the Southern Hemisphere, where it’s the opposite season, this is second of three winter full moons.

By season, we are referring to the time period between the June solstice and the September equinox.

A lovely shot of the June 10, 2017, moon from Peter Ryan in East Greenwich, Rhode Island.

It’s very hard to tell when a moon is precisely full just by looking at it. This month’s moon turns precisely full on August 3 at 15:59 UTC (translate UTC to your time). At U.S. time zones, that translates to 11:59 a.m. EDT, 10:59 a.m. CDT, 9:59 a.m. MDT, 8:59 a.m. PST, 7:59 a.m. AKDT, and 5:59 a.m. HST. But those times indicate only the crest of the moon’s full phase. They indicate when the moon is most opposite the sun for this month (180 degrees from the sun in ecliptic longitude).

Submit your full moon photo to EarthSky Community Photos

To the eye, on the other hand, the moon appears over 99% illuminated for about a day before and after full moon. People around the world will regard the moon as full on both August 2 and August 3.

Visit Unitarium.com or Heavens-Above.com to know how much of the moon’s face is illuminated in sunlight for right now or any chosen time.

At about the time of the full moon, the moon rises in the east around sunset, climbs highest up for the night around midnight and sets in the west around sunrise. So these next few nights, look for the moon in your eastern sky at dusk and your western sky at dawn.

Want to know the exact time for the full moon at your locality, plus the moonrise and moonset times? Sunrise Sunset Calendars gives the times. Remember to check the Moon phases and Moonrise and moonset boxes.

This August 2020 full moon does not pass through the antisolar point – the point that’s exactly opposite the sun – or else this full moon would undergo a total lunar eclipse. The last time the full moon passed through the antisolar point and through the center of the Earth’s dark umbral shadow was over two years ago, when it staged the longest total lunar eclipse of the 21st century (2001 to 2100) on July 27, 2018.

The July 27, 2018, eclipsed moon rises over the observatories of Instituto Astrofisica de Canarias, in Tenerife. Roberto Porto acquired 200 images to make this star trail composite. See more photos of the July 27, 2018, lunar eclipse.

Last month, in July 2020, the full moon missed the antisolar point and swung south of Earth’s dark umbral shadow. Yet the moon did clip the southern portion of the Earth’s faint penumbral shadow to present a partial penumbral eclipse on July 5, 2020.

The full moon won’t sweep through the Earth’s umbra again until May 26, 2021. But the moon will swing well north of the antisolar point, to display the second-shortest total lunar eclipse of the 21st century (2001 to 2100).

The full moon won’t meet up with the antisolar point until it barely grazes the center of the Earth’s dark shadow during the total lunar eclipse of May 16, 2022.

The worldwide map below shows the day and night sides of Earth at the instant of the August 2020 full moon (August 3, 2020, at 15:59 UTC). The shadow line at left represents sunrise August 3 whereas the shadow line at the right depicts sunset August 3.

You have to be on the nighttime side of Earth to see the moon at the instant it turns full.

The day and night sides of Earth at the instant of full moon (August 3, 2020, at 15:59 UTC). The shadow line at left (running across the Pacific Ocean) depicts sunrise August 3, and the shadow line at right (running across Africa and the Middle east) represents sunset August 3. Worldwide map via EarthView.

Bottom line: On both August 2 and 3, 2020, the brilliant full moon drenches the nighttime with moonlight from dusk until dawn. A full moon now means a last quarter moon – shining in the sky between midnight and dawn – on August 11, one of the peak mornings of this year’s Perseid meteor shower.

from EarthSky https://ift.tt/2YXLxHv

Perseid meteors 2020: All you need to know

View at EarthSky Community Photos. | James Younger caught this colorful meteor on July 26, 2020, over the Salish Sea, from the shores of British Columbia in Canada. Was it a Perseid? The shower was rising to a peak then. The Perseids are known for being colorful. And this meteor is coming from the right direction. So possibly! Thank you, James!

The annual Perseid meteor shower is one of the most beloved meteor showers of the year, especially in the Northern Hemisphere, where the shower peaks on warm summer nights. No matter where you live worldwide, the 2020 Perseid meteor shower will probably produce the greatest number of meteors on the mornings of August 11, 12 and 13. On the peak mornings in 2020, the moon will be at or slightly past its last quarter phase, so moonlight will somewhat mar this year’s production. Still, there are some ways you can minimize the moon and optimize your chances for a good display of Perseids this year. Here are some thoughts:

1. The Perseids tend to be bright, and a good percentage of them should be able to overcome the moonlight. Who knows? You still might see up to 40 to 50 meteors per hour at the shower’s peak, even in the light of a bright moon. Will you see over 100 per hour, as in some years? Not likely. Still …

2. Try to watch after midnight but before moonrise. In a typical year, meteor numbers increase after midnight. But – before dawn on all three peak mornings (August 11, 12 and 13) – fairly bright moonlight will flood the sky. Be aware that the Perseid meteors will start to fly in mid-to-late evening from northerly latitudes. South of the equator, the Perseids start to streak the sky around midnight. On each of the three peak mornings, there will be less and less moonlight. Visit the Sunrise Sunset Calendars site to find out when the moon sets in your sky on each of those mornings, remembering to check the moonrise and moonset box. Here’s an added bonus for evening observing. If fortune smiles upon you, the evening hours might offer you an earthgrazer – a looooong, slow, colorful meteor traveling horizontally across the evening sky. Earthgrazer meteors are rare but memorable. Perseid earthgrazers appear before midnight, when the radiant point of the shower is close to the horizon.

3. Watch in moonlight, but place yourself in the moon’s shadow. Just place some large structure or natural object – a barn, a cabin, a mountain – between you and the moon. You’ll see more meteors that way than if you’re standing out under the blazing moonlight itself.

4. Consider watching after the peak. People tend to focus on the peak mornings of meteor showers, and that’s entirely appropriate. But meteors in annual showers – which come from streams of debris left behind in space by comets – typically last weeks, not days. Perseid meteors have been streaking across our skies since around July 17. We’ll see Perseids for 10 days or so after the peak mornings on August 11, 12 and 13, though at considerably reduced numbers. Yet, each day as the moon wanes in the morning sky, less moonlight will obtrude on the show. Starting on or around August 17, moon-free skies reign all night long.

Also remember, the the Delta Aquariid meteor shower is still rambling along steadily. You’ll see mostly Perseids, but also some Delta Aquariids in the mix. There’s an explanation of how to tell the difference toward the bottom of this article.

In the Northern Hemisphere, we rank the August Perseids as an all-time favorite meteor shower of every year. For us, this major shower takes place during the lazy, hazy days of summer, when many families are on vacation. And what could be more luxurious than taking a siesta in the heat of the day and watching this summertime classic in the relative coolness of night?

Looking for a dark area to observe from? Check out EarthSky’s worldwide Best Places to Stargaze map.

The radiant point for the Perseid meteor shower is in the constellation Perseus. But you don’t have to find a shower’s radiant point to see meteors. Instead, the meteors will be flying in all parts of the sky.

What is the radiant point for the Perseid meteor shower? If you trace all the Perseid meteors backward, they all seem to come from the constellation Perseus, near the famous Double Cluster. Hence, the meteor shower is named in the honor of the constellation Perseus the Hero.

However, this is a chance alignment of the meteor shower radiant with the constellation Perseus. The stars in Perseus are light-years distant while these meteors burn up about 60 miles (100 km) above the Earth’s surface. If any meteor survives its fiery plunge to hit the ground intact, the remaining portion is called a meteorite. Few – if any – meteors in meteor showers become meteorites, however, because of the flimsy nature of comet debris. Most meteorites are the remains of asteroids.

In ancient Greek star lore, Perseus is the son of the god Zeus and the mortal Danaë. It is said that the Perseid shower commemorates the time when Zeus visited Danaë, the mother of Perseus, in a shower of gold.

From mid-northern latitudes, the constellation Perseus, the stars Capella and Aldebaran, and the Pleiades cluster light up the northeast sky in the wee hours after midnight on August nights. The meteors radiate from Perseus. Photo: Till Credner, AlltheSky.com

Here’s a cool binocular object to look for while you’re watching the meteors. The constellation Cassiopeia points out the famous Double Cluster in the northern tip of the constellation Perseus. Plus, the Double Cluster nearly marks the radiant of the Perseid meteor shower. Photo by Flickr user madmiked.

General rules for Perseid-watching. No special equipment, or knowledge of the constellations, needed.

Find a dark, open sky to enjoy the show. An open sky is essential because these meteors fly across the sky in many different directions and in front of numerous constellations.

Give yourself at least an hour of observing time, because the meteors in meteor showers come in spurts and are interspersed with lulls. Remember, your eyes can take as long as 20 minutes to adapt to the darkness of night. So don’t rush the process.

Know that the meteors all come from a single point in the sky. If you trace the paths of the Perseid meteors backwards, you’d find they all come from a point in front of the constellation Perseus. Don’t worry about which stars are Perseus. Just enjoying knowing and observing that they all come from one place on the sky’s dome.

Enjoy the comfort of a reclining lawn chair. Bring along some other things you might enjoy also, like a thermos filled with a hot drink.

Remember … all good things come to those who wait. Meteors are part of nature. There’s no way to predict exactly how many you’ll see on any given night. Find a good spot, watch, wait.

You’ll see some.

Composite of 12 images acquired on August 13, 2017, by Felix Zai in Toronto. He wrote: “Perseid meteor shower gave a good show even though the moonlight drowned out most of the fainter ones. A huge fireball was captured in this photo.” Thanks, Felix! By the way, it’s only in a meteor “storm” that you’d see this many meteors at once. Even in a rich shower, you typically see only 1 or 2 meteors at a time.

What’s the source of the Perseid meteor shower? Every year, from around July 17 to August 24, our planet Earth crosses the orbital path of Comet Swift-Tuttle, the parent of the Perseid meteor shower. Debris from this comet litters the comet’s orbit, but we don’t really get into the thick of the comet rubble until after the first week of August. The bits and pieces from Comet Swift-Tuttle slam into the Earth’s upper atmosphere at some 130,000 miles (210,000 km) per hour, lighting up the nighttime with fast-moving Perseid meteors.

If our planet happens to pass through an unusually dense clump of meteoroids – comet rubble – we’ll see an elevated number of meteors. We can always hope!

Comet Swift-Tuttle has a very eccentric – oblong – orbit that takes this comet outside the orbit of Pluto when farthest from the sun, and inside the Earth’s orbit when closest to the sun. It orbits the sun in a period of about 133 years. Every time this comet passes through the inner solar system, the sun warms and softens up the ices in the comet, causing it to release fresh comet material into its orbital stream.

Comet Swift-Tuttle last reached perihelion – closest point to the sun – in December 1992 and will do so next in July 2126.

The Perseids happen every year. Their parent comet – Swift-Tuttle – takes about 130 years to orbit the sun once. It last rounded the sun in the early 1990s and is now far away. But we see the Perseids each year, when Earth intersects the comet’s orbit, and debris left behind by Swift-Tuttle enters our atmosphere. Chart via Guy Ottewell.

Bottom line: The 2020 Perseid meteor shower is expected to produce the most meteors in the predawn hours of August 11, 12 and 13, though under the light of a moon at or just past first quarter phase.

Everything you need to know: Delta Aquariid meteor shower

EarthSky’s 2020 meteor shower guide

from EarthSky https://ift.tt/2OavTIz

View at EarthSky Community Photos. | James Younger caught this colorful meteor on July 26, 2020, over the Salish Sea, from the shores of British Columbia in Canada. Was it a Perseid? The shower was rising to a peak then. The Perseids are known for being colorful. And this meteor is coming from the right direction. So possibly! Thank you, James!

The annual Perseid meteor shower is one of the most beloved meteor showers of the year, especially in the Northern Hemisphere, where the shower peaks on warm summer nights. No matter where you live worldwide, the 2020 Perseid meteor shower will probably produce the greatest number of meteors on the mornings of August 11, 12 and 13. On the peak mornings in 2020, the moon will be at or slightly past its last quarter phase, so moonlight will somewhat mar this year’s production. Still, there are some ways you can minimize the moon and optimize your chances for a good display of Perseids this year. Here are some thoughts:

1. The Perseids tend to be bright, and a good percentage of them should be able to overcome the moonlight. Who knows? You still might see up to 40 to 50 meteors per hour at the shower’s peak, even in the light of a bright moon. Will you see over 100 per hour, as in some years? Not likely. Still …

2. Try to watch after midnight but before moonrise. In a typical year, meteor numbers increase after midnight. But – before dawn on all three peak mornings (August 11, 12 and 13) – fairly bright moonlight will flood the sky. Be aware that the Perseid meteors will start to fly in mid-to-late evening from northerly latitudes. South of the equator, the Perseids start to streak the sky around midnight. On each of the three peak mornings, there will be less and less moonlight. Visit the Sunrise Sunset Calendars site to find out when the moon sets in your sky on each of those mornings, remembering to check the moonrise and moonset box. Here’s an added bonus for evening observing. If fortune smiles upon you, the evening hours might offer you an earthgrazer – a looooong, slow, colorful meteor traveling horizontally across the evening sky. Earthgrazer meteors are rare but memorable. Perseid earthgrazers appear before midnight, when the radiant point of the shower is close to the horizon.

3. Watch in moonlight, but place yourself in the moon’s shadow. Just place some large structure or natural object – a barn, a cabin, a mountain – between you and the moon. You’ll see more meteors that way than if you’re standing out under the blazing moonlight itself.

4. Consider watching after the peak. People tend to focus on the peak mornings of meteor showers, and that’s entirely appropriate. But meteors in annual showers – which come from streams of debris left behind in space by comets – typically last weeks, not days. Perseid meteors have been streaking across our skies since around July 17. We’ll see Perseids for 10 days or so after the peak mornings on August 11, 12 and 13, though at considerably reduced numbers. Yet, each day as the moon wanes in the morning sky, less moonlight will obtrude on the show. Starting on or around August 17, moon-free skies reign all night long.

Also remember, the the Delta Aquariid meteor shower is still rambling along steadily. You’ll see mostly Perseids, but also some Delta Aquariids in the mix. There’s an explanation of how to tell the difference toward the bottom of this article.

In the Northern Hemisphere, we rank the August Perseids as an all-time favorite meteor shower of every year. For us, this major shower takes place during the lazy, hazy days of summer, when many families are on vacation. And what could be more luxurious than taking a siesta in the heat of the day and watching this summertime classic in the relative coolness of night?

Looking for a dark area to observe from? Check out EarthSky’s worldwide Best Places to Stargaze map.

The radiant point for the Perseid meteor shower is in the constellation Perseus. But you don’t have to find a shower’s radiant point to see meteors. Instead, the meteors will be flying in all parts of the sky.

What is the radiant point for the Perseid meteor shower? If you trace all the Perseid meteors backward, they all seem to come from the constellation Perseus, near the famous Double Cluster. Hence, the meteor shower is named in the honor of the constellation Perseus the Hero.

However, this is a chance alignment of the meteor shower radiant with the constellation Perseus. The stars in Perseus are light-years distant while these meteors burn up about 60 miles (100 km) above the Earth’s surface. If any meteor survives its fiery plunge to hit the ground intact, the remaining portion is called a meteorite. Few – if any – meteors in meteor showers become meteorites, however, because of the flimsy nature of comet debris. Most meteorites are the remains of asteroids.

In ancient Greek star lore, Perseus is the son of the god Zeus and the mortal Danaë. It is said that the Perseid shower commemorates the time when Zeus visited Danaë, the mother of Perseus, in a shower of gold.

From mid-northern latitudes, the constellation Perseus, the stars Capella and Aldebaran, and the Pleiades cluster light up the northeast sky in the wee hours after midnight on August nights. The meteors radiate from Perseus. Photo: Till Credner, AlltheSky.com

Here’s a cool binocular object to look for while you’re watching the meteors. The constellation Cassiopeia points out the famous Double Cluster in the northern tip of the constellation Perseus. Plus, the Double Cluster nearly marks the radiant of the Perseid meteor shower. Photo by Flickr user madmiked.

General rules for Perseid-watching. No special equipment, or knowledge of the constellations, needed.

Find a dark, open sky to enjoy the show. An open sky is essential because these meteors fly across the sky in many different directions and in front of numerous constellations.

Give yourself at least an hour of observing time, because the meteors in meteor showers come in spurts and are interspersed with lulls. Remember, your eyes can take as long as 20 minutes to adapt to the darkness of night. So don’t rush the process.

Know that the meteors all come from a single point in the sky. If you trace the paths of the Perseid meteors backwards, you’d find they all come from a point in front of the constellation Perseus. Don’t worry about which stars are Perseus. Just enjoying knowing and observing that they all come from one place on the sky’s dome.

Enjoy the comfort of a reclining lawn chair. Bring along some other things you might enjoy also, like a thermos filled with a hot drink.

Remember … all good things come to those who wait. Meteors are part of nature. There’s no way to predict exactly how many you’ll see on any given night. Find a good spot, watch, wait.

You’ll see some.

Composite of 12 images acquired on August 13, 2017, by Felix Zai in Toronto. He wrote: “Perseid meteor shower gave a good show even though the moonlight drowned out most of the fainter ones. A huge fireball was captured in this photo.” Thanks, Felix! By the way, it’s only in a meteor “storm” that you’d see this many meteors at once. Even in a rich shower, you typically see only 1 or 2 meteors at a time.

What’s the source of the Perseid meteor shower? Every year, from around July 17 to August 24, our planet Earth crosses the orbital path of Comet Swift-Tuttle, the parent of the Perseid meteor shower. Debris from this comet litters the comet’s orbit, but we don’t really get into the thick of the comet rubble until after the first week of August. The bits and pieces from Comet Swift-Tuttle slam into the Earth’s upper atmosphere at some 130,000 miles (210,000 km) per hour, lighting up the nighttime with fast-moving Perseid meteors.

If our planet happens to pass through an unusually dense clump of meteoroids – comet rubble – we’ll see an elevated number of meteors. We can always hope!

Comet Swift-Tuttle has a very eccentric – oblong – orbit that takes this comet outside the orbit of Pluto when farthest from the sun, and inside the Earth’s orbit when closest to the sun. It orbits the sun in a period of about 133 years. Every time this comet passes through the inner solar system, the sun warms and softens up the ices in the comet, causing it to release fresh comet material into its orbital stream.

Comet Swift-Tuttle last reached perihelion – closest point to the sun – in December 1992 and will do so next in July 2126.

The Perseids happen every year. Their parent comet – Swift-Tuttle – takes about 130 years to orbit the sun once. It last rounded the sun in the early 1990s and is now far away. But we see the Perseids each year, when Earth intersects the comet’s orbit, and debris left behind by Swift-Tuttle enters our atmosphere. Chart via Guy Ottewell.

Bottom line: The 2020 Perseid meteor shower is expected to produce the most meteors in the predawn hours of August 11, 12 and 13, though under the light of a moon at or just past first quarter phase.

Everything you need to know: Delta Aquariid meteor shower

EarthSky’s 2020 meteor shower guide

from EarthSky https://ift.tt/2OavTIz

Return of the extremely elongated cloud on Mars

View larger. | These images of the cloud, which can reach up to 1,100 miles (1,800 km) in length, were taken on July 17 an 19, 2020, by the Visual Monitoring Camera (VMC) on Mars Express, which has been studying Mars from orbit for the past 16 years. Image via ESA

EarthSky’s yearly crowd-funding campaign is in progress. In 2020, we are donating 8.5% of all incoming revenues to No Kids Hungry. Click to learn more and donate.

For the past couple of years, the European Space Agency’s (ESA) Mars Express spacecraft has been keeping an eye on a mysteriously long, thin cloud that periodically shows up over Arsia Mons, the 12 mile (20 km) high volcano on Mars.

In a July 29 statement, ESA said the cloud has appeared again, illustrated by the images above, taken by the Visual Monitoring Camera (VMC) on Mars Express on July 17 and 19, 2020.

Mars Express first noticed and photographed the cloud in September 2018. A recurrent feature, the cloud is made up of water and ice and can stretch for over 1,100 miles (1,800 km). Despite its location and appearance, scientists say it’s not a plume linked to volcanic activity. Instead, the curious stream forms as airflow, influenced by the volcano’s leeward slope (the side that does not face the wind).

Here’s the cloud, extending west of the Arsia Mons volcano on Mars, seen in a Mars Express image taken October 10, 2018. Click here for an annotated version of this image, which is via ESA.

Jorge Hernandez-Bernal, at the University of the Basque Country (Spain), is leader of a team studying the cloud. He said in a statement:

We have been investigating this intriguing phenomenon and were expecting to see such a cloud form around now. This elongated cloud forms every martian year during this season around the southern solstice, and repeats for 80 days or even more, following a rapid daily cycle. However, we don’t know yet if the clouds are always quite this impressive.

A martian day, or sol, is slightly longer than an Earth day at 24 hours, 39 minutes and 35 seconds long. A Martian year consists of 668 sols – approximately 687 days – so the seasons last for twice as long. The southern solstice is the period of the year when the sun is in the southernmost position in the martian skies, just like December 21-22 solstice here on Earth. In the early mornings during this period, this fleeting cloud grows for about 3 hours, quickly disappearing again just a few hours later.

Most spacecraft in orbit around Mars tend to observe in the afternoon, however Mars Express is in a privileged position to gather and provide crucial information on this unique effect. Mars Express mission team member Eleni Ravanis works specifically for the VMC instrument. She said:

The extent of this huge cloud can’t be seen if your camera only has a narrow field of view, or if you’re only observing in the afternoon. Luckily for Mars Express, the highly elliptical orbit of the spacecraft, coupled with the wide field of view of the VMC instrument, lets us take pictures covering a wide area of the planet in the early morning. That means we can catch it!

The Mars Express science team have named the cloud the Arsia Mons Elongated Cloud, AMEC. So, for how long has it been disappearing and reappearing? Why does it only form in the early morning? Scientists continue to investigate.

Bottom line: Images from the Mars Express spacecraft show that mysteriously long, thin cloud has again appeared over the Arsia Mons volcano on Mars.

Via ESA

from EarthSky https://ift.tt/3k0Qc77

View larger. | These images of the cloud, which can reach up to 1,100 miles (1,800 km) in length, were taken on July 17 an 19, 2020, by the Visual Monitoring Camera (VMC) on Mars Express, which has been studying Mars from orbit for the past 16 years. Image via ESA

EarthSky’s yearly crowd-funding campaign is in progress. In 2020, we are donating 8.5% of all incoming revenues to No Kids Hungry. Click to learn more and donate.

For the past couple of years, the European Space Agency’s (ESA) Mars Express spacecraft has been keeping an eye on a mysteriously long, thin cloud that periodically shows up over Arsia Mons, the 12 mile (20 km) high volcano on Mars.

In a July 29 statement, ESA said the cloud has appeared again, illustrated by the images above, taken by the Visual Monitoring Camera (VMC) on Mars Express on July 17 and 19, 2020.

Mars Express first noticed and photographed the cloud in September 2018. A recurrent feature, the cloud is made up of water and ice and can stretch for over 1,100 miles (1,800 km). Despite its location and appearance, scientists say it’s not a plume linked to volcanic activity. Instead, the curious stream forms as airflow, influenced by the volcano’s leeward slope (the side that does not face the wind).

Here’s the cloud, extending west of the Arsia Mons volcano on Mars, seen in a Mars Express image taken October 10, 2018. Click here for an annotated version of this image, which is via ESA.

Jorge Hernandez-Bernal, at the University of the Basque Country (Spain), is leader of a team studying the cloud. He said in a statement:

We have been investigating this intriguing phenomenon and were expecting to see such a cloud form around now. This elongated cloud forms every martian year during this season around the southern solstice, and repeats for 80 days or even more, following a rapid daily cycle. However, we don’t know yet if the clouds are always quite this impressive.

A martian day, or sol, is slightly longer than an Earth day at 24 hours, 39 minutes and 35 seconds long. A Martian year consists of 668 sols – approximately 687 days – so the seasons last for twice as long. The southern solstice is the period of the year when the sun is in the southernmost position in the martian skies, just like December 21-22 solstice here on Earth. In the early mornings during this period, this fleeting cloud grows for about 3 hours, quickly disappearing again just a few hours later.

Most spacecraft in orbit around Mars tend to observe in the afternoon, however Mars Express is in a privileged position to gather and provide crucial information on this unique effect. Mars Express mission team member Eleni Ravanis works specifically for the VMC instrument. She said:

The extent of this huge cloud can’t be seen if your camera only has a narrow field of view, or if you’re only observing in the afternoon. Luckily for Mars Express, the highly elliptical orbit of the spacecraft, coupled with the wide field of view of the VMC instrument, lets us take pictures covering a wide area of the planet in the early morning. That means we can catch it!

The Mars Express science team have named the cloud the Arsia Mons Elongated Cloud, AMEC. So, for how long has it been disappearing and reappearing? Why does it only form in the early morning? Scientists continue to investigate.

Bottom line: Images from the Mars Express spacecraft show that mysteriously long, thin cloud has again appeared over the Arsia Mons volcano on Mars.

Via ESA

from EarthSky https://ift.tt/3k0Qc77