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Stuart Gary: This is Space Time series 26 episode 79 for
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broadcast on the third of July 2023. Coming up on Space Time,
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new questions about whether Jupiter's ice moon Europa could
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actually host life. A new survey studies, the blue super giants
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and weak magnetic fields detected on MARS. All that and
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more coming up on Space Time.
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Generic: Welcome to Space Time with Stuart Garry.
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Stuart Gary: A new study has raised some concerning questions
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about whether the sub surface oceans on the Jovian Ice Moon
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Europa could actually host life for years. Scientists have
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speculated that Europa's oceans could contain chemical nutrients
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capable of potentially providing a habitable environment for some
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sort of life beyond Earth.
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After all entire ecosystems based around chemo synthesis
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populate the deep sea, mid ocean ridges of Earth and scientists
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speculate that these isolated colonies may be where life on
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Earth began. Europa, which is only slightly smaller than
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Earth's moon contains more liquid water than all the
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Earth's oceans combined. The water is contained in the
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massive sub surface global ocean protected from space by a thick
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icy crust.
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Observations of Europa have revealed occasional plumes of
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water ejecting out into space through fishes in the ice.
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Scientists have long speculated that Europa is made up of four
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distinct layers. There's the icy shell which we see below. That
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is the deep saltwater ocean which we know is there. Then
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there would be a rocky mantle.
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And finally at the center, a metallic core, they think that
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like the Earth, Europa's oceans touches a rocky sea floor which
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may allow rock water chemistry to interact, which would be
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favorable for life to exist. And like Earth's mid ocean ridges,
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it's possible the European sea floor. And yes, that's how you
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say it may host volcanoes which could then provide more energy
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and nutrients for a potential biosphere.
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However, a team of researchers from Arizona State University
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undertaking computer simulations of how Europa may have formed
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have come up with some shocking results. Kevin Trinny Carver,
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Berson and Joe o'rourke were investigating the consequences
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of Europa actually forming with low initial internal
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temperatures.
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Most studies of Europa suggest that its waters derive from
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hydrated rocks that is rocks containing hydrogen and oxygen
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creating an ocean of metamorphic origin. Renny and colleagues
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show that if Europa indeed was formed from hydrated rocks, then
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enough of Europa's interior should get hot enough to release
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water directly from these hydrated rocks to form the ocean
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and icy shell.
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Trenny says the origins of Europa's moon is important
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because the moon's potential to support life. Ultimately depends
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on the chemical ingredients and physical conditions during the
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ocean's formation process.
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Many scientists studying the icy moon simply assume that Europa,
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like most planetary bodies formed with a metallic core
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either during or shortly after its accion. But the Arizona
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state authors reporting in the journal science advances
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contradicts that prediction. Instead arguing that Europa may
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not have started forming its metallic core until billions of
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years after accretion.
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Assuming it happened at all, you see, for most worlds, we think
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that their internal structure was pretty well set shortly
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after they finished forming. But this study is reframing Europa
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showing it to be a world whose interior has been slowly
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evolving over its entire existence. And that opens the
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door for future research to understand how these changes
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might be observed in the Europa.
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We see today see the existence of a metallic core is deeply
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tied to Europa's internal heat which may also be used to drive
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sea floor volcanism and contribute to a habitable sea
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floor environment. Problem is it's unclear right now as to
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whether Europa generates enough heat to form such core.
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The author's work calculates how heat is generated and
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distributed throughout the moon. And they do this using the same
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governing equations that many geodynamic systems have been
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using for decades. The team's novel result however, comes from
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challenging the assumptions common to Roper's modeling, a
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small moon like Europa could form as a cold mixture of ice
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rock and metal.
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Remember Europa's really only got about one per cent of
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Earth's mass. So you can't really think of it the same way
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you think of the Earth, it means Europa may not generate enough
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energy to trigger or sustain earthlike processes such as
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metallic core formation, sea floor volcanism or ongoing rock
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water geochemistry and all that implies Europa's true.
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Habitable potential is uncertain. The exact time at
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which Europa formed determines how much heat is available from
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the radioactive decay of short lived isotopes such as aluminum,
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short tidal heating from gravitational interactions with
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Jupiter.
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And the other Jovian moons also governs how quickly Roper's
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interior separates into distinct layers. The simple fact is
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Europa's sea floor may be cool hydrated and experienced limited
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if any sea floor volcanism and that implies there may be very
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little if any hydrothermal activity which would hinder
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habitability.
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Now, NASA's Hubble Space telescope has taken direct
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ultraviolet images of Europa as it transits across the disk of
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Jupiter. And on some of these transits, it spotted water vapor
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plumes erupting from beneath the Euro surface.
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Now, similar geysers have been detected spewing out of the
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South Pole tiger stripes on the Saturnian Ice Moon Enceladus,
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which also contains a global subsurface ocean and the
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composition of these plumes were carefully studied by NASA's
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Cassini spacecraft as it was exploring the Saturnian system.
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Cassini found the Sloan plumes contained a variety of minerals
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and chemicals suitable for a habitable ocean.
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NASA plans on launching the Europa Clipper mission in
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October 2024. It'll arrive in the Jovian system in April 2030.
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Once there, it too will search for plumes of water erupting
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from beneath the European surface. Only. Then can we be
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sure as to whether or not Europa's oceans are indeed
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habitable. This report from NASA TV, NASA's.
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Guest: Hubble Space telescope has directly imaged what may be
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plumes of water vapor on Jupiter's icy moon. Europa.
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Europa has long been thought to harbor a global ocean of water
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beneath its surface of ice, making it a prime target of
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study for anyone interested in searching for alien life.
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Eventually, our search for life will take us into that ocean.
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But until then, the existence of a water vapor plume would
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provide an early glimpse into the ocean's conditions.
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In 2012. A team of astronomers used the Hubble Space telescope
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to observe a faint aurora from the interaction of Europa and
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Jupiter's magnetic field. They detected emissions in
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wavelengths characteristic of the break up of water molecules.
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And after considering a wide variety of causes, the team
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concluded that the most plausible explanation for these
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spectroscopic measurements was the existence of plumes of water
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vapor erupting from the surface of Europa. Now, a different team
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of astronomers has used a different method with similar
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results.
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They used Hubble to image Europa in ultraviolet light as the moon
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transited across the disk of Jupiter and were actually able
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to take direct images of what appear to be the silhouettes of
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plumes rising about 125 miles above the surface of Europa. If
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these observations are indeed of water vapor plumes, then they
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approximately match the 2012 observation estimates for the
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plume's mass height and location.
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Also, these plumes are transient, meaning they come and
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they go out of 10 observations of Europa transiting across
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Jupiter. The team saw possible plumes on just three of the
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transits. Both the recent observations and the 2012
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observations provide evidence not proof of water vapor plumes
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on Europa science is a process. It's not always cut and dried.
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But future observations by Hubble and infrared observations
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by the James Webb space telescope could continue to
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build a case for the existence of these plumes on Europa. And
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then NASA's future Europa fly by mission would continue the
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search for the plumes and visit them to look for evidence of a
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habitable underwater world.
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Stuart Gary: This Space Time still to come. A new study looks
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at the biggest stars of all the blue super giants. And China's
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Yong MARS Rover discovers weak magnetic fields on the Martian
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surface. All that are more still to come on Space Time.
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Astronomers have undertaken a major survey looking at some of
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the universe's most massive stars, the so called blue super
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giants. The hope is to eventually unlock some of their
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secrets.
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The observations reported in the journal Astronomy And
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Astrophysics examine some 750 of these massive stars within an
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area 6500 light years from Earth making this one of the most
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complete and highest quality samples ever undertaken.
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Understanding these giants is important because stars are the
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basic elements of construction of Galaxies and therefore of the
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observable universe.
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But among the many different types of stars, there are some
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whose masses are more than eight times that of the sun. These
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massive stars with their intense radiation and powerful stellar
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winds impart a significant impact on the surrounding
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interstellar medium.
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And the interiors of these massive stars are major chemical
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factories, changing the entire composition of the universe,
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these stars during their lifetimes and when they die,
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produce all the elements on the periodic table, other than the
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hydrogen and helium, which is produced in the Big Bang 13.82
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billion years ago.
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And that makes them crucial, not just for the chemical evolution
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of the universe, but also for the appearance of life itself
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being so massive. These blue super giants burn through their
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nuclear fuel supplies really quickly, usually living for just
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a few million years compared to the 12 billion year life span
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for smaller stars like our sun.
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Previous studies of these giants hasn't been able to obtain
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enough information to really understand these stars in
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detail. That's where this survey's come in. It's spent the
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past 15 years obtaining specter of these behemoths, thereby
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providing high resolution details of their composition.
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The study's lead author Abel De Burgos Sierra from the Canary
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Islands Institute Of Astrophysics says these stellar
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fingerprints will allow astronomers to tackle some of
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the big questions about the evolutionary nature and physical
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properties of these giants questions which have gone for
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decades without solution because they were less well known than
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other types of stars were less mass to find these massive but
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still fairly rare stars in the universe.
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A new method of flagging was used based on an easily
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identifiable tracer in the specter of these stars, the
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shape of the profile of their hydrogen beta line. This allowed
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for the rapid identification of the stars with a specific range
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of temperatures and surface gravity.
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Rather than going through the usual method of complex spectral
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analysis based on stellar atmospheres. Astronomers are now
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planning a new five year program in order to observe and catalog
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many more of these stars with the ultimate aim of producing
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the largest ever database of the specter of these massive stars
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within the milky way galaxy.
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This is Space Time still to come. New data from the surface
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of MARS shows that its magnetic field is much weaker than
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expected. And later in the science report, a new survey
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links increased use of vitamin D supplements to reducing the risk
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of heart problems. All that are more still to come on Space
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Time.
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New data released from China's Marjon Rover shows that the
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local magnetic field where the rover was operating is far
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weaker than anyone expected The data reported in the Journal
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Nature Astronomy indicates the magnetic field strength in the
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Utopia Basin region where the rover was running was an order
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of magnitude weaker than at the location where NASA's MARS
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Insight Lander touched down some 2000 kilometers away to the
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South East.
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The findings are based on recordings taken during the
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rover's first kilometer of travel across the red planet's
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surface. And the extremely weak intensity of the magnetic field
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suggests no detectable magnetization anomalies below
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Giro's landing site. Shero is the first rover equipped with
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magnetometers.
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The researchers utilized two flux gate magnetometers aboard
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the rover to conduct the first magnetic field survey of the
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Utopia Basin. The results from the MARS Insight Lander were an
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order of magnitude stronger than that inferred from orbital
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measurements.
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But the measurements from Jurong revealed the opposite result
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with the average intensity in order less than what was
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inferred from orbit. The extremely weak magnetic field
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detected by the Jurong rover implies that either the crust
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beneath the Utopia Basin may have remained unm mats since its
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formation 4 billion years ago or it was demagnetized by a later
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sizable impact probably during the early heper in epoch.
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This new constraint on the timeline of the Martian dynamo
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sheds further light on the interconnected magnetic climatic
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and interior history of the early red planet.
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This Space Time and time. Now to take a brief look at some of the
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other stories making news in science this week. With the
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science report, a new study has shown that vitamin D supplements
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could play a modest role in reducing the risk of heart
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attacks, strokes and other heart problems.
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Previous studies had linked low vitamin D levels with increased
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heart risks. The new findings reported in the British Medical
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Journal follow a randomized test of over 20 people between
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the ages of 16, 84 who received either vitamin D supplements or
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a placebo to see if this impacted the risk of heart
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problems.
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And after following up for an average of five years,
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scientists say 6.6 per cent of the placebo group ended up
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experiencing a major heart event such as a stroke or heart attack
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compared to six per cent of the vitamin D supplement group.
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The authors say that while the difference in risk is small, it
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does support the need for more research to find out exactly
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what the role vitamin D plays in the cardiovascular system is
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likely to be and how this could help people who already have
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heart issues.
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A record 315 babies were born in Australia in 2021.
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That's the highest annual figure on record. The data is contained
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in a report from the Australian Institute Of Health And Welfare.
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It shows the birth rate in 2021 was 61 births for every 1000
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women of productive age. That's up from 56 births per 1000 in
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2020.
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The findings also show that women are continuing to give
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birth later in life with one in four women giving birth aged 35
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or older during the year. Now, despite their health risks of
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having a baby later in life, the report shows more than nine in
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10 babies born to women aged 35 and over were born at term and
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at a healthy weight.
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Ok. If you're like me and you feel a coffee in the morning is
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needed in order to get energized for the day. Well, Spanish and
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Portuguese researchers say that boost you're getting could all
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be in your head because they can't replicate it with plain
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caffeine.
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The scientists scanned the brains of regular coffee
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drinkers and then gave them either a cup of coffee or the
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equivalent amount of caffeine and then scanned their brains a
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second time.
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The findings reported in the journal Frontiers Of Behavioral
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Neuroscience showed that while both coffee and regular caffeine
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activated areas of the brain that make you more alert areas
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of the brain associated with working memory and goal directed
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behavior were only activated by those who had the cup of coffee.
00:17:43
And while we're on the subject of things that may be affecting
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us, not quite the way we think they do. A new study has
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questioned the link between sugar consumption and kids going
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wild. Tim Mendham from Australian Skeptics says, while
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we've all seen kids getting hyperactive after consuming
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candy and cake at a party, it turns out the connection isn't
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really there.
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Tim Mendham: Sugar and hyperactivity. There's nothing
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better than going to a kid's birthday party and finding 20
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little children rushing around like crazy bumping into each
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other playing the musical instruments. They've just been
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given all the horns on the drum guaranteed to help insanity. The
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suggestion is that sugar plays a big part in that in
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hyperactivity.
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You give a kid a colorful cordial drink or a lot of
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Christmas birthday cake, et cetera that they will then go
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around and go berserk. Everyone sees it that you give a kid a
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birthday cake, an association which is not there. They see an
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association which are not necessarily there. Kids running
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around at the birthday party is not unusual whether they've had
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cake or not.
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So the interesting thing is someone's done a bit of research
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on this has kids and looked at it. There's probably no way that
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a single serve of some sugary concoction will make kids go
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hyperactive, give them a diet based on sugar everywhere. And
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of course sugar is in basically everything we eat.
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But you know, give them a high sugar content in their complete
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diet. Yes, then you might have particular health issues. But
00:19:01
this one off thing of don't give a kid a glass of cordial because
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beer is not well founded. In fact, this person points out
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that this particular myth has it origin in one published
00:19:12
scientific article, which they might consider it unethical.
00:19:15
Today, this thing from the 19 seventies and this study
00:19:18
examined the effects of foods on the autistic behavior of one
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child. So you got a study of one and there was one paper that
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blew up this thing out of well proportion that sugar was
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considered one of the foods that caused disruptive behavior. And
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it's really unfounded now, people would think.
00:19:33
Oh, yeah, it has become a commonplace belief, not true as
00:19:37
far as the scientific evidence goes. And the later analysis and
00:19:40
stuff has not necessarily done any greater service in
00:19:42
supporting the theory. But sugar comes in all forms and shapes
00:19:46
and sizes and there's various sugars in everything.
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And there's four key sugars that molecules, different molecules
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and they combine and they form others that are forms of sugar,
00:19:55
etcetera. And you look at quite glucose, fructose, galactose and
00:19:58
ribose, which have in different, which is four out of more than
00:20:01
20 sugars that you might find in the foods you're eating. And
00:20:04
these four combine and do different things.
00:20:06
Sometimes they do it by themselves and sometimes
00:20:08
together. And so that is the issue with these sugars. It's
00:20:12
probably long term overdose of sugar that causes these sort of
00:20:16
problems and it's not just hyperactivity, it could be
00:20:18
diabetes or all sorts of things, but a single cake at a birthday
00:20:21
party is not going to do a lot of damage over the three.
00:20:23
Stuart Gary: Or four bits of candy they had before they went
00:20:25
to the party. That's the.
00:20:27
Tim Mendham: That study suggests that really what parents are
00:20:30
seeing is a cause and effect that doesn't exist. They find a
00:20:33
correlation then as we say, correlation does not mean
00:20:35
causation, but just because you see two things happening at the
00:20:38
one time doesn't mean A causes B and that spread, it spread
00:20:42
everywhere.
00:20:42
Stuart Gary: That's Tim Mendham from Australian Skeptics.
00:21:01
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