Scientists Describe How Solar System Could Have Formed In Bubble Around Giant Star

Despite the many impressive discoveries humans have made about the universe, scientists are still unsure about the birth story of our solar system.

Scientists with the University of Chicago have laid out a comprehensive theory for how our solar system could have formed in the wind-blown bubbles around a giant, long-dead star. Published Dec. 22 in the Astrophysical Journal, the study addresses a nagging cosmic mystery about the abundance of two elements in our solar system compared to the rest of the galaxy.

The general prevailing theory is that our solar system formed billions of years ago near a supernova. But the new scenario instead begins with a giant type of star called a Wolf-Rayet star, which is more than 40 to 50 times the size of our own sun. They burn the hottest of all stars, producing tons of elements which are flung off the surface in an intense stellar wind. As the Wolf-Rayet star sheds its mass, the stellar wind plows through the material that was around it, forming a bubble structure with a dense shell.

“The shell of such a bubble is a good place to produce stars,” because dust and gas become trapped inside where they can condense into stars, said coauthor Nicolas Dauphas, professor in the Department of Geophysical Sciences. The authors estimate that 1 percent to 16 percent of all sun-like stars could be formed in such stellar nurseries.

This setup differs from the supernova hypothesis in order to make sense of two isotopes that occur in strange proportions in the early solar system, compared to the rest of the galaxy. Meteorites left over from the early solar system tell us there was a lot of aluminium-26. In addition, studies, including a 2015 one by Dauphas and a former student, increasingly suggest we had less of the isotope iron-60.

This brings scientists up short, because supernovae produce both isotopes. “It begs the question of why one was injected into the solar system and the other was not,” said coauthor Vikram Dwarkadas, a research associate professor in Astronomy and Astrophysics.

This brought them to Wolf-Rayet stars, which release lots of aluminium-26, but no iron-60.

“The idea is that aluminum-26 flung from the Wolf-Rayet star is carried outwards on grains of dust formed around the star. These grains have enough momentum to punch through one side of the shell, where they are mostly destroyed — trapping the aluminum inside the shell,” Dwarkadas said. Eventually, part of the shell collapses inward due to gravity, forming our solar system.

As for the fate of the giant Wolf-Rayet star that sheltered us: Its life ended long ago, likely in a supernova explosion or a direct collapse to a black hole. A direct collapse to a black hole would produce little iron-60; if it was a supernova, the iron-60 created in the explosion may not have penetrated the bubble walls, or was distributed unequally.

Other authors on the paper included UChicago undergraduate student Peter Boyajian and Michael Bojazi and Brad Meyer of Clemson University.

Mars: Not As Dry As It Seems

When searching for life, scientists first look for an element key to sustaining it: fresh water.

Although today’s Martian surface is barren, frozen and inhabitable, a trail of evidence points to a once warmer, wetter planet, where water flowed freely. The conundrum of what happened to this water is long standing and unsolved. However, new research published in Nature suggests that this water is now locked in the Martian rocks.

Scientists at Oxford’s Department of Earth Sciences, propose that the Martian surface reacted with the water and then absorbed it, increasing the rocks oxidation in the process, making the planet uninhabitable.

Previous research has suggested that the majority of the water was lost to space as a result of the collapse of the planet’s magnetic field, when it was either swept away by high intensity solar winds or locked up as sub-surface ice. However, these theories do not explain where all of the water has gone.

Convinced that the planet’s minerology held the answer to this puzzling question, a team led by Dr Jon Wade, NERC Research Fellow in Oxford’s Department of Earth Sciences, applied modelling methods used to understand the composition of Earth rocks to calculate how much water could be removed from the Martian surface through reactions with rock. The team assessed the role that rock temperature, sub-surface pressure and general Martian make-up, have on the planetary surfaces.

The results revealed that the basalt rocks on Mars can hold approximately 25 per cent more water than those on Earth, and as a result drew the water from the Martian surface into its interior.

Dr Wade said: ‘People have thought about this question for a long time, but never tested the theory of the water being absorbed as a result of simple rock reactions. There are pockets of evidence that together, leads us to believe that a different reaction is needed to oxidise the Martian mantle. For instance, Martian meteorites are chemically reduced compared to the surface rocks, and compositionally look very different. One reason for this, and why Mars lost all of its water, could be in its minerology.

‘The Earth’s current system of plate tectonics prevents drastic changes in surface water levels, with wet rocks efficiently dehydrating before they enter the Earth’s relatively dry mantle. But neither early Earth nor Mars had this system of recycling water. On Mars, (water reacting with the freshly erupted lavas’ that form its basaltic crust, resulted in a sponge-like effect. The planet’s water then reacted with the rocks to form a variety of water bearing minerals. This water-rock reaction changed the rock mineralogy and caused the planetary surface to dry and become inhospitable to life.’

As to the question of why Earth has never experienced these changes, he said: ‘Mars is much smaller than Earth, with a different temperature profile and higher iron content of its silicate mantle. These are only subtle distinctions but they cause significant effects that, over time, add up. They made the surface of Mars more prone to reaction with surface water and able to form minerals that contain water. Because of these factors the planet’s geological chemistry naturally drags water down into the mantle, whereas on early Earth hydrated rocks tended to float until they dehydrate.’

The overarching message of Dr Wade’s paper, that planetary composition sets the tone for future habitability, is echoed in new research also published in Nature, examining the Earth’s salt levels. Co-written by Professor Chris Ballentine of Oxford’s Department of Earth Sciences, the research reveals that for life to form and be sustainable, the Earth’s halogen levels (Chlorine, Bromine and Iodine) have to be just right. Too much or too little could cause sterilisation. Previous studies have suggested that halogen level estimates in meteorites were too high. Compared to samples of the meteorites that formed the Earth, the ratio of salt to Earth is just too high.

Many theories have been put forward to explain the mystery of how this variation occurred, however, the two studies combined elevate the evidence and support a case for further investigation. Dr Wade said ‘Broadly speaking the inner planets in the solar system have similar composition, but subtle differences can cause dramatic differences — for example, rock chemistry. The biggest difference being, that Mars has more iron in its mantle rocks, as the planet formed under marginally more oxidising conditions.’

We know that Mars once had water, and the potential to sustain life, but by comparison little is known about the other planets, and the team are keen to change that.

Dr Wade, said: ‘To build on this work we want to test the effects of other sensitivities across the planets — very little is known about Venus for example. Questions like: what if the Earth had more or less iron in the mantle, how would that change the environment? What if the Earth was bigger or smaller? These answers will help us to understand how much of a role rock chemistry determines a planet’s future fate.

When looking for life on other planets it is not just about having the right bulk chemistry, but also very subtle things like the way the planet is put together, which may have big effects on whether water stays on the surface. These effects and their implications for other planets have not really been explored.’

New Discovery Finds Atarving White Dwarfs Are Binge Eaters

University of Canterbury astrophysicist Dr Simone Scaringi has made an unexpected and exciting new discovery related to the way white dwarfs grow in space.

The New Zealand-based researcher and astrophysics lecturer’s co-authored paper, titled “Magnetically gated accretion in an accreting ‘non-magnetic’ white dwarf” has been published in the latest issue of Nature (14 December).

A white dwarf is what stars like the Sun become after they have exhausted their nuclear fuel. White dwarfs are dense objects roughly the same size as Earth but with as much mass as the Sun. They accrete, or grow, by sucking in mass from the outer layers of their companion stars.

Most white dwarfs have long been considered “non-magnetic”. When white dwarfs grow at very low rates, they gain mass in distinct and sudden bursts where they ‘binge eat’ for a short period of time, Dr Scaringi says.

By examining several years of data from the Kepler space-based observatory, a team of international researchers found one of these non-magnetic white dwarfs behaving as if it had a strong magnetic field.

“We have seen episodes of strong flares of accretion interrupted by periods with no evidence of accretion. This sporadic activity is best explained by the presence of a strong magnetic field comparable to that of 1000 fridge magnets,” Dr Scaringi says.

“This magnetic field ‘gates’ the accretion, causing the matter to pile up until it has a gravitational attraction stronger than the magnetic forces holding it back, indicating for the first time that even “non-magnetic” white dwarfs can have very strong magnetic fields.”

The paper’s primary author, Dr Scaringi says this is fundamental research for the field. There have been hints that accretion disks essentially behave in the same way independent of the accretor – whether that is a white dwarf, black hole, neutron star or young proto-star.

“Now we have further evidence that magnetic accretors like the one in our paper also behave in the same way, irrespective of their origin.

“Similar bursts have been observed in accreting neutron stars – which are much smaller and have magnetic fields much higher than our white dwarf – and in young stellar objects, which are on the other end, being much larger and owning much weaker magnetic fields,” he says.

“Our result closes the gap in that our new observations of accretion bursts in MV Lyrae [a peculiar nova-like star consisting of a red dwarf and a white dwarf in Lyra constellation] show the magnetic field strength distribution of systems displaying magnetic gating and underscores the universality of magnetospheric accretion across an enormous range of stellar parameters.”

JUST IN: Scientists Seem To Be Very Interested In Cosmic Rays

There is a great deal of interest in galactic cosmic rays coming from our best space agencies and top universities. As evidenced by several recently published studies, the interest is in the relatively new understanding associated with the paradoxical effect between solar minimum and cosmic ray acceleration.

A second focused interest is the physical effects of higher rates of radiation on humans and animals. Commercial airlines are flying at lower altitudes, and pilots and flight attendants have reduced their number of long flights as well as over polar region flights.

A closer watch has been placed on the Earth’s weakening magnetic field, which of course has always been our greatest defense against charged particles. I think it also important to highlight the ongoing interest and new studies on transcranial magnetic stimulation and its effect on the brain, much of which is related to emotions.

Is it time to go underground? Should we bring out the aluminum hats and umbrellas? No, not yet anyway. I would suggest this generation and the next is not likely to be burdened with such things, but perhaps a hundred years from now there may be inter-planetary travel.

Coming in next newsletter, I will be placing perhaps five or so of the latest published studies for you to perhaps grasp and contemplate on this fascinating direction of research. Not just from looking into the future, but looking into the past.

Then of course, there will be a few of you already have an understanding of this science of cycles. Perhaps you may have even found a source who has produced the inside story on how this puzzle plays out – maybe even since 2012 :-).

Cheers, Mitch

Mars Mission Sheds Light On Habitability Of Distant Planets

How long might a rocky, Mars-like planet be habitable if it were orbiting a red dwarf star? It’s a complex question but one that NASA’s Mars Atmosphere and Volatile Evolution mission can help answer.

“The MAVEN mission tells us that Mars lost substantial amounts of its atmosphere over time, changing the planet’s habitability,” said David Brain, a MAVEN co-investigator and a professor at the Laboratory for Atmospheric and Space Physics at the University of Colorado Boulder. “We can use Mars, a planet that we know a lot about, as a laboratory for studying rocky planets outside our solar system, which we don’t know much about yet.”

At the fall meeting of the American Geophysical Union on Dec. 13, 2017, in New Orleans, Louisiana, Brain described how insights from the MAVEN mission could be applied to the habitability of rocky planets orbiting other stars.

MAVEN carries a suite of instruments that have been measuring Mars’ atmospheric loss since November 2014. The studies indicate that Mars has lost the majority of its atmosphere to space over time through a combination of chemical and physical processes. The spacecraft’s instruments were chosen to determine how much each process contributes to the total escape.

In the past three years, the Sun has gone through periods of higher and lower solar activity, and Mars also has experienced solar storms, solar flares and coronal mass ejections. These varying conditions have given MAVEN the opportunity to observe Mars’ atmospheric escape getting cranked up and dialed down.

Brain and his colleagues started to think about applying these insights to a hypothetical Mars-like planet in orbit around some type of M-star, or red dwarf, the most common class of stars in our galaxy.

The researchers did some preliminary calculations based on the MAVEN data. As with Mars, they assumed that this planet might be positioned at the edge of the habitable zone of its star. But because a red dwarf is dimmer overall than our Sun, a planet in the habitable zone would have to orbit much closer to its star than Mercury is to the Sun.

The brightness of a red dwarf at extreme ultraviolet (UV) wavelengths combined with the close orbit would mean that the hypothetical planet would get hit with about 5 to 10 times more UV radiation than the real Mars does. That cranks up the amount of energy available to fuel the processes responsible for atmospheric escape. Based on what MAVEN has learned, Brain and colleagues estimated how the individual escape processes would respond to having the UV cranked up.

Their calculations indicate that the planet’s atmosphere could lose 3 to 5 times as many charged particles, a process called ion escape. About 5 to 10 times more neutral particles could be lost through a process called photochemical escape, which happens when UV radiation breaks apart molecules in the upper atmosphere.

Because more charged particles would be created, there also would be more sputtering, another form of atmospheric loss. Sputtering happens when energetic particles are accelerated into the atmosphere and knock molecules around, kicking some of them out into space and sending others crashing into their neighbors, the way a cue ball does in a game of pool.

Finally, the hypothetical planet might experience about the same amount of thermal escape, also called Jeans escape. Thermal escape occurs only for lighter molecules, such as hydrogen. Mars loses its hydrogen by thermal escape at the top of the atmosphere. On the exo-Mars, thermal escape would increase only if the increase in UV radiation were to push more hydrogen to the top of the atmosphere.

Altogether, the estimates suggest that orbiting at the edge of the habitable zone of a quiet M-class star, instead of our Sun, could shorten the habitable period for the planet by a factor of about 5 to 20. For an M-star whose activity is amped up like that of a Tasmanian devil, the habitable period could be cut by a factor of about 1,000 — reducing it to a mere blink of an eye in geological terms. The solar storms alone could zap the planet with radiation bursts thousands of times more intense than the normal activity from our Sun.

However, Brain and his colleagues have considered a particularly challenging situation for habitability by placing Mars around an M-class star. A different planet might have some mitigating factors — for example, active geological processes that replenish the atmosphere to a degree, a magnetic field to shield the atmosphere from stripping by the stellar wind, or a larger size that gives more gravity to hold on to the atmosphere.

“Habitability is one of the biggest topics in astronomy, and these estimates demonstrate one way to leverage what we know about Mars and the Sun to help determine the factors that control whether planets in other systems might be suitable for life,” said Bruce Jakosky, MAVEN’s principal investigator at the University of Colorado Boulder.

Shifting Shield Provides Protection Against Cosmic Rays

The Sun plays an important role in protecting us from cosmic rays, energetic particles that pelt us from outside our solar system. But can we predict when and how it will provide the most protection, and use this to minimize the damage to both piloted and robotic space missions?

The Challenge of Cosmic Rays

Galactic cosmic rays are high-energy, charged particles that originate from astrophysical processes-like supernovae or even distant active galactic nuclei – outside of our solar system.

One reason to care about the cosmic rays arriving near Earth is because these particles can provide a significant challenge for space missions traveling above Earth’s protective atmosphere and magnetic field. Since impacts from cosmic rays can damage human DNA, this risk poses a major barrier to plans for interplanetary travel by crewed spacecraft. And robotic missions aren’t safe either: cosmic rays can flip bits, wreaking havoc on spacecraft electronics as well.

Shielded by the Sun

Conveniently, we do have some broader protection against galactic cosmic rays: a built-in shield provided by the Sun. The interplanetary magnetic field, which is embedded in the solar wind, deflects low-energy cosmic rays from us at the outer reaches of our solar system, decreasing the flux of these cosmic rays that reach us at Earth.

This shield, however, isn’t stationary; instead, it moves and changes as the strength and direction of the solar wind moves and changes. This results in a much lower cosmic-ray flux at Earth when solar activity is high – i.e., at the peak of the 11-year solar cycle – than when solar activity is low. This visible change in local cosmic-ray flux with solar activity is known as “solar modulation” of the cosmic ray flux at Earth.

In a new study, a team of scientists led by Nicola Tomassetti (University of Perugia, Italy) has modeled this solar modulation to better understand the process by which the Sun’s changing activity influences the cosmic ray flux that reaches us at Earth.

Modeling a Lag

Tomassetti and collaborators’ model uses two solar-activity observables as inputs: the number of sunspots and the tilt angle of the heliospheric current sheet. By modeling basic transport processes in the heliosphere, the authors then track the impact that the changing solar properties have on incoming galactic cosmic rays. In particular, the team explores the time lag between when solar activity changes and when we see the responding change in the cosmic-ray flux.

By comparing their model outputs to the large collection of time-dependent observations of cosmic-ray fluxes, Tomassetti and collaborators show that the best fit to data occurs with an ~8-month lag between changing solar activity and local cosmic-ray flux modulation.

This is an important outcome for studying the processes that affect the cosmic-ray flux that reaches Earth. But there’s an additional intriguing consequence of this result: knowledge of the current solar activity could allow us to predict the modulation that will occur for cosmic rays near Earth an entire 8 months from now! If this model is correct, it brings us one step closer to being able to plan safer space missions for the future.

JUST IN: New Report Shows Atmospheric Radiation Increasing via Cosmic Rays

As you might have guessed, this is no surprise to this researcher. It is good to see the science community taking this scenario very seriously. What’s a bit different is the choice to go public with this hard hitting evidence highlighting the consequence of Earth’s weakening magnetic field, along with Cycle 24’s solar activity reaching solar minimum.

I am once again humbled to bring evidence showing my research is months, sometimes a year or two or three, ahead of fundamental science communities.

As a brief reminder, the less intensity of solar activity such as coronal mass ejections (CMEs), solar flares, and coronal holes – the greater amount of galactic cosmic rays enter Earth’s atmosphere, and the higher charged particles penetrate Earth’s lithosphere, and in my personal research, has an influence down to the mantle.

Last week’s double launch of space weather balloons over Mexico and California was a success. The goal of the experiment was to measure cosmic rays in the atmosphere above both countries and compare the results. A first look at the data reveal big differences.

These curves show dose rate vs. altitude. They diverge rapidly above ~15,000 feet, with radiation levels over central California typically 1.5 times higher than over Mexico. This means air travelers over California can expect to receive significantly greater doses of cosmic radiation compared to their counterparts flying south of the border. In both places, radiation levels reached a peak in the stratosphere. At those altitudes, radiation dose rates were 60 times greater than sea level for Mexico, 90 times greater than sea level for California.

The reason for these differences is Earth’s magnetic field which, generally speaking, provides greater shielding against cosmic rays near the equator (Mexico) than at mid-latitudes (California). The radiation sensors onboard our helium balloons detect X-rays and gamma-rays in the energy range 10 keV to 20 MeV. They trace secondary cosmic rays, the spray of debris created when primary cosmic rays from deep space hit the top of Earth’s atmosphere.

Soon after our monitoring program began, we quickly realized that radiation levels were increasing. Why? The main reason is the solar cycle. In recent years, sunspot counts have plummeted as the Sun’s magnetic field weakens. This has allowed more cosmic rays from deep space to penetrate the solar system. As 2017 winds down, our latest measurements show the increase continuing at pace–with an interesting exception due to an influx of a large X9.3 solar flare.

In Sept. 2017, the quiet Sun surprised space weather forecasters with a sudden outburst of explosive activity. On Sept. 3rd, a huge sunspot appeared. In the week that followed, it unleashed the strongest solar flare in more than a decade (X9-class), hurled a powerful CME toward Earth, and sparked a severe geomagnetic storm (G4-class). During the onslaught we quickened the pace of balloon launches and found radiation dropping to levels we hadn’t seen since 2015. The flurry of solar flares and CMEs actually pushed some cosmic rays away from Earth.

Interestingly, after the Sun’s outburst radiation levels in the stratosphere took more than 2 months to fully rebound. Now they are back on track, increasing steadily as the quiet Sun resumes its progress toward Solar Minimum. The fact that we can make these measurements over California shows that you do not have to travel to polar regions to experience space weather. We have known charged particles can effect weather patterns worldwide.


Update on Kids Christmas Fund

We have been able to place a few wonderful gifts under the tree for my two beautiful daughters thanks to you. If it’s possible, I will try to fulfill their Christmas list the best I can. There are two big items each has asked for. ———–Alexa (9yrs) wants one of those new hoover boards. Sophia (5yrs) wants an AmericanGirl doll “Tenney”.

For those seeing this for the first time, there really is no need to explain further this uncomfortable position I’ve put myself in. Because of my choices some years ago to venture off into independent research and publishing – I am learning, mostly the hard way, to navigate the peaks and valleys of not having that comfortable umbrella of the more structured agencies. We all make our choices – so it is what it is.
Cheers, Mitch

Here’s wishing you a Merry Christmas and a Happy New Year! Wishing you lots of love, joy and happiness. May your Christmas sparkle with moments of love, laughter and goodwill, And may the year ahead be full of contentment and joy.

Kids Christmas Fund