This blog provides commentary on interesting geological events occurring around the world in the context of my own work. This work is, broadly, geological fluid dynamics. The events that I highlight here are those that resonate with my professional life and ideas, and my goal is to interpret them in the context of ideas I've developed in my research. The blog does not represent any particular research agenda. It is written on a personal basis and does not seek to represent the University of Illinois, where I am a professor of geology and physics. Enjoy Geology in Motion! I would be glad to be alerted to geologic events of interest to post here! I hope that this blog can provide current event materials that will make geology come alive.

Banner image is by Ludie Cochrane..

Susan Kieffer can be contacted at s1kieffer at gmail.com

Friday, July 24, 2015

#PacificWarmBlobMustDie--a fun article by Scott Sistek on our warm and dry Northwest

Photo from Scott Sistek article
July 23, 2015 Komonews.com

I don't usually just reference a news article, but this one today by Scott Sistek in KOMONEWS.COM is a great read, and explains the # in the title of this post:


Thursday, July 23, 2015

Kepler spots potentially habitable planet like our Earth

Temperature of the Earth under present
conditions with a solar flux of 341 W/m2,
and just before the runaway greenhouse is triggered
for a mean solar flux of 375 W/m2.
From the Leconte et al. article referenced in text.
NASA has just released an announcement this morning that the Kepler spacecraft has spotted a planet about 60% bigger than our Earth in a habitable zone of a star "similar to our sun."  The planet is dubbed Kepler-452b, and it's about 1400 light years from Earth in the constellation Cygnus. It's gravity would be about twice that of the Earth's. The star around which it orbits is a G2-type star like our sun, has the same temperature, is 20% brighter, and has a diameter about 10% larger.
Cover of Science in 2014
     Aside: Todays announcement is  a bit confusing because a year ago the Kepler team had the cover photo and a report in Science (v. 344, no. 6181, pp. 277-280, 2014) titled "An Earth-Sized Planet in the Habitable Zone of a Cool Star." This star has a radius of about 1/2 that of our sun, but the planet, Kepler 186f, is in the habitable zone and could support liquid water if it has an earth-like atmosphere and water at the surface. It appears that the difference between these two announcements is that the star around which Kepler-452b orbits is more similar to our sun than the Kepler 186f star.

      In 2013, Sid Perkins wrote a piece in Nature (December 11, 2013) discussing the habitable zone and summarizing the work of Jeremy Leconte at the Pierre Simon Laplace Institute in Paris (Leconte et al., Nature, 504, 268, 2013).  Leconte ran the first fully three dimensional model of hot, very moist planetary atmospheres (and thus the work only applies to planets that have abundant water like the Earth; there is no evidence yet whether the newly discovered planet in Cygnus has water). Previous models had been one-dimensional and considered only how the atmospheric conditions changed in the vertical direction, ignoring horizontal transport effects, whereas this model can take account of the Hadley circulation. Leconte et al. conclude that the runaway greenhouse will take effect at a mean solar insolation of about 375 W/m2. In this model, warming of the planet causes the formation of cirrus clouds at high altitudes. Such clouds trap heat, and the heating leads to more evaporation, which leads to more clouds and thus the feedback to a greenhouse effect. The model also suggests that the large-scale circulation (not possible in 1-D models) creates cloud-free areas in the mid-latitudes that allow heat to radiate back to space. The conclusion is that the inner edge of the Solar System's habitable zone is about 142 million kilometers from the sun.  Earth is at 149,600,000 kilometers so we are close to the inner edge of the habitable zone. Other authors, however, have concluded that the inner boundary could be considerably closer especially for planets that have much less water to feed the greenhouse effect (Petigura, et. al., Proc. Natl. Acad. Sci. USA 110, 19723, 2013).
     Wiki has a good summary of habitable zone thermodynamics here.

Monday, July 20, 2015

Recommended Readings!

From this web site
I don't usually post reviews or recommended readings, but at the behest of a couple of valued readers, here are two that are highly recommended:

On the scale of future disasters in the Pacific Northwest, Kathyryn Schulz "The Really Big One," is eloquent, accurate, and incredibly readable:


And, a moving tribute to Claudia Alexandra, a prominent African American planetary scientist/engineer, who tragically died at age 56:


Tuesday, July 14, 2015

Pluto, at last!!

The last photo of Pluto for a bit, hopefully more soon.
New Horizons' should reestablish contact with earth
Tuesday night (7/14/2015) and begin sending 10 years
worth of data back to earth, a process that will take 16 months.
NASA image.
Congratulations to Alan Stern and the teams on New Horizon, the spacecraft that has spent a decade getting out to Pluto! To emphasize what a feat this is, here's a quote from a NASA press release:

"New Horizons' almost 10-year, three-billion-mile journey to closest approach at Pluto took about one minute less than predicted when the craft was launched in January 2006. The spacecraft threaded the needle through a 36 by 57 mile (60 by 90 kilometers) window in space--the equivalent of a commercial airliner arriving no more off target than the width of a tennis ball."

Pluto was discovered only 85 years ago by Clyde Tombaugh, an astronomer at the Lowell Observatory in Flagstaff. Tombaugh was doing a systematic search for a planet, dubbed "Planet X" at the time, beyond the orbit of Neptune. He would take photographs of the sky several nights apart and compare the images using a "blink comparator," an image that allowed rapid comparison of images. With this technique, astronomers can distinguish between stars, which do not move, and moving objects such as asteroids, comets and, in Tombaugh's case, a planet. It showed up very close to the place that Lowell had predicted.
Kuiper Belt (blue dots). Attribution:
WilyD at English Wikipedia
The yellow dot is the sun.
J,S,U,N are Jupiter, Saturn, Uranus, and Neptune.

Pluto resides in a region of the Solar System known as the Kuiper belt, shown in the image here.  It was believed, until the 1990's, that Pluto was uniquely large and the Kuiper belt objects were unknown. Hence, Pluto was called a planet. The Kuiper belt was discovered in the 1990's, causing some to call Pluto's status as a planet into question, and with the discovery of Eris in 2005, a body 27% more massive than pluto, Pluto's status was sealed. The International Astronomical Union had to define the term "planet" for the first time because there was the possibility of "too many" planets!! To the dismay of some (many?) Pluto was demoted to a "dwarf planet" category.

So, what are the basics known or believed to be known at this point? The size of Pluto had been uncertain, and one result already from New Horizons is a new diameter--2370 km, up from an earlier value of 2302 km. This diameter is only about 2/3 of the diameter of the Moon. It's acceleration of gravity is 0.067 g, escape velocity is 1.23 km/s. The surface temperature varies between 33-55 K, with a mean of 44 K, truly a frigid planet. It's atmosphere consists of nitrogen, methane, and carbon monoxide at a maximum summer pressure of 0.30 Pa. The surface is 98% nitrogen ice. The color varies from black to dark orange to white--being similar to that of Io (the satellite of Jupiter that looks like a pizza).

Is there the possibility that tectonic or "volcanic/geyser" activity will be discovered on Pluto? The interior is believed to have a dense rocky core of approximately 1700 km diameter, and if radioactive heating is still significant today, it's been speculated that there could be a subsurface ocean 100-180 km thick at the core-mantle boundary.  Here's a New Horizon's blurb that summarizes some of the facts and possibilities. We've been surprised before (Io, Triton, Enceladus) so here's hoping for some action!!

Go New Horizons Team, and thank you!!

Monday, July 13, 2015

New prediction of a "mini ice age" during the 2030's

A sun without any sunspots, photo taken on July 17, 2014
Photo from here.
I am reluctant to feature research here that hasn't been through peer-review, but it's a losing battle as prestigious groups, such as the British Royal Astronomical Society, release press releases about exciting ideas. So, take the following for what it is worth, it's at least interesting to think about!

Here is the reference for the press release.

The sun's activity varies over a solar cycle of roughly 11 years (22 years if the polarity of sunspots is considered). To date, the cycle has been analyzed the phenomenon in terms of a dynamo driven by fluids convecting deep within the sun. A dynamo is a fluid dynamic condition of convection within a body that moves a convecting, rotating, and electrically charged fluid around within a body. Traditionally, solar physicists attempt to explain the measured properties of the sun and their variability with a single dynamo within the sun. We had a prolonged drought of sunspots over the past two years, but there are a few now and they emit strong enough particles to cause some concerns about telecommunications.
Sun configuration on July 13, 2015
From space weather.com

Valentina Zharkova is presenting a paper at the National Astronomy Meeting in Llandudno that proposes two dynamos: the traditional one deep in the sun, and another close to the surface. Each dynamo gives a periodicity of about 11 years, but they are slightly different and offset in time. The idea is that if they coincide appropriately, the effects will be large. The data are based on observations from 1976-2008. Running the model into the future, the model predicts that during Cycle 25, which peaks in 2022,  and into cycle 26 (2030-2040) the waves due to the two dynamos will become exactly out of synch. This would result in a reduction in solar activity equivalent to the Maunder minimum of the 1600's, 370 years ago.

It will be interesting to follow this because the implications are enormous for global stability and economics. I recommend the great website space weather.com to follow solar events.

For a bit of prehistory, and my interest in the sun, my first published paper was a documentation of the evolution of sunspot groups, in the inaugural edition of a new journal Solar Physics: Zirin, Harold and Werner, Susan, Detailed analysis of flares, magnetic fields and activity in the sunspot group of Sept. 13-26, 1963, Solar Physics, 1, pp. 66-100, 1967,