Thursday, December 18, 2014

NASA K2's first planet discovery


Cambridge, MA - To paraphrase Mark Twain, the report of the Kepler spacecraft's death was greatly exaggerated. Despite a malfunction that ended its primary mission in May 2013, Kepler is still alive and working. The evidence comes from the discovery of a new super-Earth using data collected during Kepler's "second life."

"Like a phoenix rising from the ashes, Kepler has been reborn and is continuing to make discoveries. Even better, the planet it found is ripe for follow-up studies," says lead author Andrew Vanderburg of the Harvard-Smithsonian Center for Astrophysics (CfA).

NASA's Kepler spacecraft detects planets by looking for transits, when a star dims slightly as a planet crosses in front of it. The smaller the planet, the weaker the dimming, so brightness measurements must be exquisitely precise. To enable that precision, the spacecraft must maintain a steady pointing.

Kepler's primary mission came to an end when the second of four reaction wheels used to stabilize the spacecraft failed. Without at least three functioning reaction wheels, Kepler couldn't be pointed accurately.

Rather than giving up on the plucky spacecraft, a team of scientists and engineers developed an ingenious strategy to use pressure from sunlight as a virtual reaction wheel to help control the spacecraft. The resulting second mission, K2, promises to not only continue Kepler's search for other worlds, but also introduce new opportunities to observe star clusters, active galaxies, and supernovae.

Due to Kepler's reduced pointing capabilities, extracting useful data requires sophisticated computer analysis. Vanderburg and his colleagues developed specialized software to correct for spacecraft movements, achieving about half the photometric precision of the original Kepler mission.

Kepler's new life began with a 9-day test in February 2014. When Vanderburg and his colleagues analyzed that data, they found that Kepler had detected a single planetary transit.

They confirmed the discovery with radial velocity measurements from the HARPS-North spectrograph on the Telescopio Nazionale Galileo in the Canary Islands. Additional transits were weakly detected by the Microvariability and Oscillations of STars (MOST) satellite.

The newfound planet, HIP 116454b, has a diameter of 20,000 miles, two and a half times the size of Earth. HARPS-N showed that it weighs almost 12 times as much as Earth. This makes HIP 116454b a super-Earth, a class of planets that doesn't exist in our solar system. The average density suggests that this planet is either a water world (composed of about three-fourths water and one-fourth rock) or a mini-Neptune with an extended, gaseous atmosphere.

This close-in planet circles its star once every 9.1 days at a distance of 8.4 million miles. Its host star is a type K orange dwarf slightly smaller and cooler than our sun. The system is 180 light-years from Earth in the constellation Pisces.

Since the host star is relatively bright and nearby, follow-up studies will be easier to conduct than for many Kepler planets orbiting fainter, more distant stars.

"HIP 116454b will be a top target for telescopes on the ground and in space," says Harvard astronomer and co-author John Johnson of the CfA.

The research paper reporting this discovery has been accepted for publication in The Astrophysical Journal.

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

For more information, contact:

David A. Aguilar
Director of Public Affairs
Harvard-Smithsonian Center for Astrophysics
617-495-7462

Christine Pulliam
Public Affairs Specialist
Harvard-Smithsonian Center for Astrophysics
617-495-7463

Sunday, December 14, 2014

Not much new under the Sun

The protests against police brutality, centered around the cases of Michael Brown and Eric Garner, have forced race into the consciousness of most Americans. Those who support the protests focus on the pattern of abuse that they represent. Those who stand in opposition of the protests tend to focus on the specific details of each killing, becoming armchair lawyers and ballistics experts. Black America sees the police killings as symptoms of systemic racism. White America, for the most part, wants to see the killings as unfortunate but isolated events divorced from racist factors. Indeed, racism isn't a thing, right?

Here's an excerpt from a blog that seems to exemplify the view of the latter group:
[T]he shooting is being used to prove a point about police discrimination in America. The means of distribution are simple: destruction of private property and interference with commerce. In other words, brute thuggery and ignominious acts of violence. 
Note the assumption that all protest necessarily must be violent. What's frustrating to me as I read more about the Civil Rights movement in the 50's and 60's---and what's so sad for people who express views like this---is that this sentiment and even the specific arguments are so very unoriginal. This author probably thought that they were penning original thoughts based on sound logical arguments. But check out what I just read in The Rebellious Life of Mrs. Rosa Parks:
The [1963 Washington D.C. march] itself now is remembered in a nostalgic glow as an inspirational and quintessentially American event, but at the same time, it was dreaded and feared by many white Americans. In a Wall Street Journal poll taken in the days leading up to the march, two-thirds denounced the idea as "un-American." Most newspapers, as well as many politicians, predicted violence...Even when the fears of violence proved unfounded, the Wall Street Journal remained critical: "This nation is based on representative Government not on Government run by street mobs, disciplined or otherwise." 
Again, Black people protesting must portend violence. Mobs then, thugs now. Back then, the Civil Rights movement terrified white America while it was happening. Very few saw the racism that drove Black people to march and protest. Very few white people saw the big deal. It's the same today as it was then. 

Fifty years later, every white liberal wants to tell you they were there marching hand-in-hand with Martin. Keeping an historical perspective is useful in understanding what is happening in Ferguson and around the country, and how historical events are viewed very differently while in progress compared to later on. I've been to several Boston-area anti-racism/anti-police-violence protests and I've witnessed zero violence from the protesters. The marches are peaceful and powerful. The cars and trucks stopped honk in support more often than in anger, particularly from drivers of color. But, of course, this doesn't matter. When Black people gather in large numbers, white people start seeing violence, whether real or imagined.

It seems only logical that anyone wishing to criticize this movement should at least go see one for themselves rather than relying on second-hand accounts filtered through popular media and their myopic Twitter feeds. But as with so many arguments and world views, when racism enters the room, logic jumps out the window. 

There's a revolution happening right now. How big will it be? How far-reaching will it go? What will result from it? History hasn't been written yet, but I'm cautiously optimistic as I  march and join in. If you have ever thought about what you would have done during the Montgomery bus boycott, or the march across the Edmund Pettus Bridge in Selma, AL, or if you would have been in D.C. that summer day in 1963, now is your time to find out what you'd do during a Civil Rights movement. Will your role be parroting the views of Wall Street Journal editorials written by racists 50 years ago. Or will you honestly get to claim that you were on the side of social justice at this key juncture in history? 


Tuesday, December 9, 2014

Black lives matter. Anyone? Anyone?


I simultaneously have much to say and little to say about the killings of Michael Brown and Eric Garner. I have much to say because these men are so similar to the Black men in my life: my uncles, cousins, nephews, my sons, myself. I don't have much to say because, hell, what is there left to say? There's only so many times I can repeat the notion that Black Lives Matter.

I keep making this argument in various forms, and from white people I keep hearing, "Yeah, it's tragic, but..." But, nothing! If people accept the radical notion that a 6'4", 240 lb Black man is a living person, a citizen of our country, and a human being with hopes, dreams, and aspirations for a better life, then there can be no "but." We live in a country where we get to hear the "good aspects" of even our serial killers, who, BTW, are predominantly white. We hear about how they were clean-cut, peaceful, good students and how their friends and loved ones couldn't imagine that their son would so something so terrible (because yes, it is usually a white male). 

But with Michael Brown? We didn't even know the name of his killer before we heard that he stole cigarillos from a local convenience store. We hear about how he was a thug. We hear about how he "rushed" the officer, how he looked like a demon. We heard only the worst aspects of Michael Brown, even though he didn't kill anyone and barely harmed that cop. You can be white and kill dozens, and we'll hear about your good side on the History Channel. If you are a Black man standing on the sidewalk before you get your life taken by a white cop, and we'll hear about every misdeed you've ever done. Sold loosie cigarettes? Well, you deserved to die.

Being killed by a police officer is relatively rare, but it's three times more likely to happen to you if you're Black than if you're white. There are fewer Black people than white people in this country, yet Black women and men are still more likely to be killed by a cop. It's relatively rare, but so is dying in a plane crash, or a terrorist attack. But these rare events carry something important in common: when it happens, it is singularly terrifying.

Wednesday, December 3, 2014

Tuesday, December 2, 2014

ExoLab Update: Ellen Price and the Photoeccentric Effect

Today's guest post is by Ellen Price, a Senior astrophysics major at Caltech. 

Professor Johnson pitched me this project idea just after I took his Introduction to Astronomy class (Ay20) in 2012. At that time, I was a sophomore with very little research experience, I knew absolutely nothing about exoplanets. In fact, I had pretty recently considered dropping my astrophysics major entirely. I felt like I had a lot of catching up to do, but classes were a lot more enjoyable when I felt like they mattered in the context of my research. Prof. Johnson’s Ay117 (Statistics and Data Analysis for Astronomers) class, for example, was immeasurably important for me – I learned scientific programming in Python and Bayesian statistics for the first time. 

I attended the Exolab group meetings and started to pick up exoplanet jargon and, eventually, I started to absorb the science, too. Prof. Johnson warned me up front that this wasn’t going to be a “packaged” project for an undergrad, and it wasn’t! By the summer following my sophomore year I was still working on it, which is when Dr. Leslie Rogers (Caltech) and Dr.Rebekah Dawson (Berkeley) got involved, bringing some new ideas and a lot of expertise. Then, the project took an interesting turn and we put it on hold temporarily so I could develop a different project, since we needed that result to move forward. Now, as a senior at Caltech, the paper is finally finished, accepted to ApJ, and posted on the arXiv. If doing research as an undergrad has taught me anything, it’s that this is really what I want to do with my life and my career.

How Low Can You Go? The Photoeccentric Effect for Planets of Various Sizes
Ellen M. Price, Leslie A. Rogers, John Asher Johnson, Rebekah I. Dawson

Monday, December 1, 2014

Are Black People Wrong About Police Abuse?

This morning, I came across this polling result regarding the police shooting of Michael Brown:


This plot, this statistical result, demands an explanation. How is it that two groups of Americans can see the world so very differently?

Setting aside any appeal to actual evidence regarding racial bias in the use of deadly force by the police, of which there is plenty, I can think of two explanations for the statistical result shown above:

Sunday, November 30, 2014

My Response to Andrew Sullivan's Thoughts on Affirmative Action


Dear Andrew,

In your recent post Thoughts on Affirmative Action, early on you claimed that the G.I. Bill "was a huge step forward for meritocracy in America." You should be very careful with your history here. As pointed out by Ira Katznelson in his book When Affirmative Action Was White (see also this NY Times book review),  Jim Crow laws and practices were baked into the G.I. Bill. The congressional "Dixiecrats" at the time ensured that the administration of G.I. Bill benefits (and Federal Housing Administration loan insurance, and WPA jobs) was left up to each state individually. This meant that Black soldiers in the South returning from WWII were often denied government benefits from these so-called meritocratic programs. Black veterans in the North were barred from buying houses in white neighborhoods, and couldn't obtain loans in Black neighborhoods due to housing shortages and the practice of redlining. 

From the NY Times book review (which is easier to copy-paste than my copy of Katznelson's book)

The statistics on disparate treatment are staggering. By October 1946, 6,500 former soldiers had been placed in nonfarm jobs by the employment service in Mississippi; 86 percent of the skilled and semiskilled jobs were filled by whites, 92 percent of the unskilled ones by blacks. In New York and northern New Jersey, ''fewer than 100 of the 67,000 mortgages insured by the G.I. Bill supported home purchases by nonwhites.'' Discrimination continued as well in elite Northern colleges. The University of Pennsylvania, along with Columbia the least discriminatory of the Ivy League colleges, enrolled only 46 black students in its student body of 9,000 in 1946. The traditional black colleges did not have places for an estimated 70,000 black veterans in 1947. At the same time, white universities were doubling their enrollments and prospering with the infusion of public and private funds, and of students with their G.I. benefits.

I challenge you to do dig deeper into this history before opining that government assistance programs represent anything approaching a meritocracy. In fact, citing the G.I. Bill provides a powerful refutal to that notion. White men were able to attain government backed housing loans and government subsidized post-graduate education via the G.I Bill. This allowed them to accumulate wealth in the decades since, while Black people were actively excluded from that process. It's almost like action was taken to affirm the place of white men in this country!

Ignorance of this history is why well-meaning and otherwise knowledgeable white people scratch their heads about the present-day 20:1 wealth gap between whites and Blacks, when we all know the number one asset for many people is the house they own. Those houses and the associated wealth were acquired by white men via America's most successful race-based affirmative action programs in history. But now that Black students are benefiting from similar programs at our universities? Suddenly it's not fair. 

Sincerely,


John A. Johnson