In the search for life in our solar system, the discussion typically revolves around Mars. But there are two moons many astronomers believe are even better bets: Saturn’s moon Enceladus and Jupiter’s moon Europa.
Now a new computer model by NASA scientists lends further support to the theory that, beneath the thick, icy crust of Europa, the Jovian moon’s interior ocean could be habitable.
Europa is the sixth-largest moon in the solar system, smaller than the Earth’s moon but larger than Pluto.
The scientists believe the moon’s ocean may have formed after water-rich minerals released their water due to heating caused by the radioactive decay of the satellite’s core. Due to its gravitational interactions with gas giant Jupiter and with other moons, the water is kept warm.
But not all water means life. Other important building blocks are needed, and researchers believe that was the case.
‘This ocean could be quite habitable’
Billions of years ago, the ocean would have been mildly acidic, but with concentrations of carbon dioxide, calcium and sulfate too high for life as we know it.
“Our simulations, coupled with data from the Hubble Space Telescope, showing chloride on Europa’s surface, suggests that the water most likely became chloride-rich,” said Mohit Melwani Daswani, a geochemist and planetary scientist at NASA’s Jet Propulsion Laboratory, who presented the recent findings at the virtual Goldschmidt conference this week.
“In other words, its composition became more like oceans on Earth. We believe that this ocean [now] could be quite habitable for life.”
Water and minerals aren’t the only thing needed for life. Life needs energy.
“It’s unlikely that any possible life forms in Europa’s ocean would use sunlight as a source of energy, because Europa is really quite far from the sun, and the ocean would be under complete darkness beneath a really thick ice shell,” Melwani Daswani said. “So we have to think about other sources of energy.”
On Earth, life exists around hydrothermal vents, openings on the ocean floor that emit dissolved minerals, and there has been strong evidence that these may exist in Europa’s subglacial ocean as well. That could be used as a source of energy for any potential life.
Melwani Daswani is cautious.
“We don’t even know whether life as we know it would be happy over there or whether the energy available for that for life would be sufficient,” he added.
Mission to Europa
Gordon Osinski, a professor in the department of Earth sciences at Western University in London, Ont., who was not involved in the study, said that this new research is another reason that missions to moons like Europa or Enceladus are so intriguing.
“I think the key take-home here is that these ocean worlds present the best likelihood for present-day habitable environments,” he said. “So, life living on those planets at the present day. All the key ingredients are there.”
NASA does have a mission in the works to visit the moon: the Europa Clipper.
The mission — the first dedicated mission to a moon other than our own — won’t be looking for signs of life, since it will only orbit, but it will look for increasing evidence of potential habitability by studying its geology, icy shell and composition.
Osinski said that it would be ideal for a future sample-return mission, where a spacecraft could even fly through and collect from plumes of water vapour that have been seen blown into space by both Europa and Enceladus through fissures in the ice.
“Because then we’ll know,” he said. “We’ll have the unequivocal determination of whether there is life there or not.”
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Your guide to spotting the NEOWISE comet – The London Free Press
Discovered at the end of March, the NEOWISE comet is passing within 100 million kilometres of our planet. “That in astronomical terms is close, but in human terms very far,” said Parshati Patel, an astrophysicist with Western University’s Institute for Earth & Space Exploration.
So don’t worry — even though Patel says comets are unpredictable, this one won’t ram into the Earth, as often happens in Hollywood movies and science-fiction paperbacks.
Comets are leftover chunks from the formation of a planet, she says, composed of dust, ice and rocks. “It’s almost like a dirty snowball in many ways,” Patel said. They appear as bright spots, with a tail, in the sky.
Patel got up early this week to catch a glimpse of NEOWISE, which gets its name from the asteroid-hunting part of NASA’s Wide-field Infrared Survey Explorer mission, an Earth-orbiting telescope that detected the object.
“I personally went on Tuesday. It wasn’t really great. There were some clouds in the sky,” Patel said. “We couldn’t really see it with the naked eye.”
ATLANTIC SKIES: How did the moon form? – SaltWire Network
There are a number of theories as to how our moon formed, or where it may have come from.
The primary one – which is backed by most lunar scientists – is called the “giant impact hypothesis.” Its premise is that the moon formed as a result of a collision, approximately 4.5 billion years ago, between the newly-formed Earth and a Mars-sized object (given the name “Theia”), with the moon forming when some of the debris coalesced around the core of Theia.
A variation of this theory has the moon forming from a number of massive objects that struck the young planet, sending up large quantities of material that eventually formed the moon.
Another variation, put forward in 2012, theorizes that the moon formed when two massive objects, five times the size of Mars, crashed into one another, with the Earth created from the majority of the collision material and the moon from the remaining debris disk that orbited the new planet.
The second theory, referred to as the “co-formation theory”, holds that the moon formed much as (and at the same time as) the Earth. It postulates that as the dust and gas in the giant molecular cloud that would eventually form our solar system coalesced into the sun and the various planets, some of that material also formed the moon. This theory provided a plausible explanation as to why the Earth and moon are very similar in material-makeup.
The final theory, called the “capture theory”, posits that the moon is a celestial object, formed elsewhere in the solar system, that was captured by Earth’s gravity. One flaw in this theory, however, is that such objects are usually oddly-shaped (e.g., some of the moons of Saturn), not spherical like our moon. A variation of the capture theory states that Earth’s gravity, at some point billions of years ago, stole the moon from Venus (which has no moon).
This week’s sky
Mercury remains too close to the sun to be seen at present.
Jupiter (magnitude -2.7) will be at opposition (directly opposite the sun as seen from Earth) on July 14. It will also be at perigee (closest approach to Earth) and will be at its biggest and brightest for the year. Binoculars will show the four Jovian moons – Io, Callisto, Europa and Ganymede – orbiting the planet. Jupiter will become visible above the southeastern horizon shortly before 10 p.m., remaining visible in the night sky (highest in the southeast at midnight) until around 4:40 a.m., when it will be lost to the approaching dawn.
Saturn (magnitude +0.17) is visible about 10 degrees above the southeastern horizon around 10:30 p.m., reaching 23 degrees above the southern horizon around 1:50 a.m., before succumbing to the dawn twilight in the southwest shortly before 5 a.m.
Mars (magnitude -0.64) is visible about 41 degrees above the southeastern horizon shortly after midnight, before fading from view shortly after 5 a.m.
Our “morning star” Venus (magnitude -4.48) shines brilliantly above the eastern horizon around 3 a.m., reaching 20 degrees above the horizon before fading from sight as dawn breaks shortly after 5 a.m.
Try and catch a glimpse of Comet C/2020 F3 NEOWISE in the constellation of Lynx in the northwest evening sky around July 15. Look to the lower right of the front feet of Ursa Major – the Great Bear, just as the sky begins to darken between 9-10 p.m. By July 23, it will be visible at the same time of night closer to the bowl of the Big Dipper asterism in Ursa Major.
Discovered in March 2020, it has now developed two tails (one gas, one dust). The comet passed perihelion on July 3 and will make its closest approach to Earth (perigee) on July 23.
Though now fading (currently estimated at magnitude +0.1), it may be visible to the naked eye under a clear, dark sky throughout the remainder of the month, with binoculars and small scopes enhancing the view; a timed photo shoot should capture the comet nicely. Google the comet online for the latest updates and finder charts.
Until next week, clear skies.
July 14 – Jupiter at opposition/perigee
Glenn K. Roberts lives in Stratford, P.E.I., and has been an avid amateur astronomer since he was a small child. He welcomes comments from readers, and anyone who would like to do so is encouraged to email him at email@example.com.
COVID affecting younger demographic – Medicine Hat News
By GILLIAN SLADE on July 8, 2020.
There is the impression that the Albertans currently being diagnosed with COVID-19 are a younger demographic.
According to the numbers released by Alberta Health on Monday, 21 per cent are between the ages of 40 and 49 years, 20 per cent are 30-to-39 years old, 15 per cent 20-to-29 years of age and 14 per cent are the 50-to-59 year demographic.
If you look at data provided by Alberta Health on 26 April, three months ago, the numbers are only slightly different. On that day 22 per cent were in the 30-to-39 year bracket, 18 per cent 40-to-49 years, 15 per cent 50-to-59 years and 14 per cent 20-to-29 years.
Since April though the testing criteria for the province has changed and this could be influencing the numbers by demographic.
“A common source of COVID-19 transmission, particularly in young people, is socializing without practising physical distancing and attending gatherings or parties with shared food and drinks,” said Tom McMillan, assistant director communications for Alberta Health.
He says there has also been an increase recently in the number of Albertans, less than 40 years of age, getting tested.
“Alberta has the broadest testing criteria in Canada, with testing available for anyone, even those without symptoms,” said McMillan.
We are also in the middle of the province’s relaunch after the lock down. McMillan says the locations of new cases has “largely shifted from continuing care environments to indoor and community settings, such as workplaces or large gatherings”.
Even though we have seen an increase in younger Albertans testing positive, everyone is at risk of catching COVID-19, said McMillan.
“It is important that we do not shame those who test positive but rather support them to isolate and work with public health to do contact tracing and follow up,” said McMillan.
According to Alberta Health’s data this week: the average age for COVID-19 cases that did not require hospitalization is 39 years. The average age for those needing hospitalization for COVID is 62, those requiring ICU is 60 years and the average age for those who died is 83 years.
It is interesting to note that only four per cent of those more than 80 years old test positive for COVID-19.
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