Monday, October 26, 2015

Clocking in: Christine's Egg Freezing Adventure

Photo credit:
We often hear about egg freezing as a recommended option for professional women who want to postpone having children to their late 30s or 40s or perhaps even later. Christine is brave enough to both go through this process and write about it so that we can have the details of what it entails.

A bit about Christine
Read Part 1 of her post here.
Christine did her PhD at the University of Zurich, and I was one of her mentors and collaborators.  She is an amazing researcher who was invited to meet President Obama three days after her PhD defense. She is also the first PhD I wrote a letter of recommendation for. I particularly enjoyed writing that my opinion of her abilities is seconded by that of the president of the United States of America.

Christine is now a researcher in astrophysics at Caltech where she holds a prestigious fellowship from the US National Science Foundation. She flies planes for fun, and is scheduled to be in Antarctica for one year starting in January 2016 for training and research.

My favorite part of her post is her statement that women come with a built-in 3D printer that creates people, and that men should be begging to use it. That is simply sublime, but I should and will refrain from elaborating further.

Note that this is a very personal choice, and we each have the right to make our own choices. It is not OK to insult or write abusive comments.

What is my opinion on the subject? Egg freezing is a good plan B if a woman plans to have children after her mid-30s. The age of the mother at the time the eggs are harvested plays a crucial role in determining the success rate of the procedure.  There are, of course, in any age pool some people who succeed naturally, some who need treatment and for whom the treatment works, and some for whom IVF fails. Young frozen eggs increase the probability of success when IVF is needed. They do not guarantee success.  This treatment is quite expensive, but, if the patient is young and healthy enough, it may be financed by selling some of the eggs.

All the female professors I have met who have families and have led discussions on the subject, regretted not having children earlier, and building a life around them vs. waiting for tenure or some other poorly defined "right time". After having a child myself, I agree with them.

Advice from Tusa Tavi
My last conversation with Tusa Tavi (the sister of my grandpa) went along the lines:
me: I passed my qualifier exams today! 
TusaTavi: That's nice, but you do have a university degree.
me: I do. I also have a Masters, and I am working towards a second Masters and a PhD.
TusaTavi: Then you can support a child.
me: I cannot have a child alone, and right now there is nobody in my life with whom I would want to have and raise a child.

TusaTavi: Well... go to class and drop a pen. See who picks it up. If you don't like them, try again.

Octavia - middle-aged
Grandpa, Mom, Ionica, Tavi & Mariana
Tusa Tavi then reminded me that she had helped raise many children above and beyond her job as a Mathematics professor.  Her last protege was still in kindergarten. Children loved her because she had always found the time to take them seriously, and listen carefully to everything they had to say. She had been there for her family, friends and neighbors, and for a number random people she met who needed her help, but the one thing she regretted was not having had a child of her own. She thought it would not have mattered so much with who. Most of the suitors had been educated and kind or seemed so from her stories. Once she had a college degree, she was able to both support herself and help family, and she thought she would have been able to support a child at any time since then. Part of her message was that she believed I could do it, too. She said that, anyhow, I should expect to do most of the bringing up myself and so I should not wait too long before starting a family.

Years later with her husband
Octavia - young
Tusa Tavi had defined propriety for me. She had always emphasized the importance of being both correct and gentle. I spent my girlhood listening to her stories. She had married late and had had plenty of suitors before that - each with a funny story of his own. She and my uncle met and started a courtship before the second world war, but only married 15 years later. At the very end, she did not regret any of her suitors, but simply wished she had had more strength and courage herself.

 She died before I went back home to visit and so we never spoke again.  She was 90 and I was 22. 

Saturday, October 17, 2015

Looking for Aliens

Ravi Kopparapu visited Zurich some time ago and gave a very interesting seminar that summarized the latest work in extrasolar planets. Some of the things I've learned are below. Note that the title comes from the description that Ravi's daughter gave of this. The actual talk title was "Habitable Zones and the Occurrence of Potential Habitable Planets in our Galaxy".

When is a planet Habitable? 
Habitable zones [Image from Ravi's website]
 A rocky planet is potentially habitable if it contains water. In our solar system, the Earth is located close to the inner edge of our habitable zone (also known as the Goldilocks zone). Mars is located close to the outer edge.  The Moon is outside our Goldilocks zone.

Ravi (together with James Kasting from Penn State University and others) built a calculator for finding habitable zones around different kind of stars. The brighter the star the further way the planet has to be to be habitable. The coolest types of stars are M-stars or red dwarfs. They are numerous and dim, and so the habitable planets in their orbits can be closer in. Planets around M-stars are also tidally locked. This means that they rotate synchronously just like the Moon does - always keeping the same side towards Earth.

Close to the inner edge of the Habitable zone, the planet has a water dominated surface like Earth. At the inner edge, the planet is so hot that most of the water has evaporated to the atmosphere, then it is no longer habitable.  At the outer edge, the temperature is low, and no amount of carbon dioxide will warm up the planet to melt the ice. For a star like our Sun, the inner edge of the habitable zone was first found to be between 0.97 to 0.99 AU, while the outer edge is at 1.6 AU. However, this model did not include could feedback.

3D models also include clouds, which reflect some of the sunlight and allow the planet to be slightly closer to the star. The inner edge of the habitable zone for a Sun-like star shifts to around 0.93 to 0.95 AU, whereas the outer edge remains unchanged (1.6 AU). Mars is at 1.5 AU, while Venus is outside the habitable zone receiving about twice as much sunlight as Earth.

It has been known for a long time (1996) that there was ice at the Martian North Pole, and beneath the surface at the South Pole. Structures and rocks on Mars also suggested the presence of flowing water. But there was no direct proof of water flowing now on the surface of Mars until the Mars Reconnaissance Orbiter has found hydrated salts. This means that very salty water still flows occasionally on Mars. 

How many planets have been found in Habitable zones?
There are about 30some known planets in the habitable zones of other stars, and out of those about 10 are Earth-sized. The numbers are so low because current technology does not allow us to see most of them, not because the planets don't exist.

How do we estimate habitability from so far away?
Life interacts with the atmosphere. We would expect to see the same kind of gases as we observe in the Earth spectrum: Oxygen, Carbon dioxide, water vapor, ozone, methane, and dominant nitrogen. Plate tectonics is also very important.  It causes volcanism, and volcanoes are believed to be what got our planet out of the various ice-ages.

Life under-surface would not interact as easily with the atmosphere, and would be harder to detect from far away.  

Snow Ball Earth
The Earth is believed to have had many ice-ages (C-Si cycle). About 700 million years ago, our planet was a snow ball. The the ice was 1 km think and reached the Equator.  There are a number of proposed triggers for the ice age - one could be the eruption of a super-volcano like Yellowstone. The carbon dioxide is taken away from the atmosphere into the subsurface of the Earth. It is called the Carbon-Silicate cycle where the surface Silicates are converted to carbonate sediments. In time carbon dioxide accumulates in the atmosphere again and the ice melts. 

How many planets do we expect around a given star?
Every star should have at least one planet of any kind orbiting it. Planets are common. They are not an exception. They exist around every star in our galaxy.

The first Earth-like planets were found more than 20 years ago. In 1992, it was found that planets could orbit pulsars. This shifts the center of mass of the system. The pulsar then wobbles around the center of mass causing millisecond delays in the pulse arrival times. 

Twenty years ago (in 1995)  Michel Mayor and Didier Queloz (Geneva Observatory, Switzerland) found the first extrasolar planet around a Sun-like star. 51 Pegasi B became a prototype for a new class of planets - the Hot Jupiters. They are big like Jupiter, but orbit very close to their stars, which induces high surface temperatures.  These planets were first found via the radial velocity method, which measures the velocity shift in the spectral lines of the star induced by the planet's gravity.

Both the temperature and mass of 51 Pegasi B are Sun-like. It has a surface temperature of over 5500 K. The light it reflects from its Sun is in the visible spectrum, and can be detected from Earth. Recent work suggests that this planet could pioneer yet another way for finding nearby extrasolar planets.

Today some 4000+ planets were found. Most were found by NASA's Kepler mission in 2009-2013 via the transit method. When the planet crosses in front of the parent star disk, the observed brightness of the star drops by a small amount. Three transits should be observed to confirm a detection.  For our Earth, a far-away alien civilization would observe one transit per year. The mission duration of four years was chosen so that Kepler could find Earth-like planets around Sun-like stars.

 How to find Alien life?  
 Keep searching and keep an open mind...

Kepler has recently found a star with an unusual a-periodic pattern. Two hypothesis were put forward: (1) a swarm of comets that are perhaps a remnant of a kind of collision and (2) an Alien
Mega-structure that perhaps consists of solar panels used by some very advanced alien civilization.
So, have we found aliens. Well... of course, not, but more data is needed, e.g., infrared and 
radio data. This is the first reasonable candidate that could be used to develop SETI methods. It is very reasonable that some more odd balls will be found when looking for planets.

Perhaps we will look at the atmosphere of habitable planets and find life outside the solar system that way or perhaps there will be some satellites built by aliens that we will see around the stars that host habitable planets. Either way it is timely to start taking SETI research seriously.

Other news
Geoffrey Marcy who led the research team that discovered the first planetary system around a Sun-like star resigned his professorship under pressure after allegations of sexual harassment. He went from being known as the finder of new worlds and being nominated for the Nobel prize to having to quit his position at Berkeley. He was also a co-Investigator of the Kepler mission. He is thus a person who changed our understanding of science.

I did not know him, but apparently his behavior had been an "open secret". So, why put the pressure now? did he disturb important enough people with unrelated behavior? was he not productive enough (he is 61) and so it did not make sense for the university to continue to cover his apparently non-criminal indiscretions? does it makes more sense to hire someone else on his position at this point? is it a combination of factors? Or is it really about setting a zero tolerance policy to sexual harassment in universities around the world? I have given up trying to understand politics for some time, and I want to think even less on these issues now that I am applying for jobs again.