Sally Ride Gets Posthumous Medal Of Freedom

Sally Ride, the first American female astronaut to go to space, will get a posthumous Medal of Freedom, the U.S. White House announced yesterday.

Ride flew aboard the shuttle Challenger in 1983. She had been part of the first class of American astronauts to include women and non-white people. (You can read about her and her colleagues' training in this 1982 issue of Popular Science.) Today, the 2013 class of NASA astronauts is diverse and includes four men and four women.

After her time with NASA, Ride worked as a physics professor at the University of California, San Diego, and founded a company, Sally Ride Science, to encourage girls to pursue science careers. She also served on NASA committees investigating the 1986 Challenger and 2003 Columbia explosions. After the Challenger accident shook Americans' faith in NASA, Ride wrote a now-famous report recommending that the agency focus equally on four goals: monitoring the Earth with satellites, exploring the solar system, establishing a base on the moon and visiting Mars with humans.

She died in 2012 at age 61.

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Why Do Stars Twinkle?

Stars appear to twinkle, planets don’t. Here's why.

Did you know you can distinguish between stars and planets in the sky?

Stars twinkle, planets don’t.

Okay, that’s not actually correct. The stars, planets, even the sun and moon twinkle, all in varying amounts. Anything outside the atmosphere is going to twinkle.

If you’re feeling a little silly using the word twinkle over and over again, we can also use the scientific term: astronomical scintillation.

You can’t feel it, but you’re carrying the entire weight of the atmosphere on your shoulders. Every single square inch of your skin is getting pushed by 15 pounds of pressure. And even though astronomers need our atmosphere to survive, it still drives them crazy. As it makes objects in space so much harder to see.

Stars twinkle, I mean scintillate, because as light passes down through a volume of air, turbulence in the Earth’s atmosphere refracts light differently from moment to moment. From our perspective, the light from a star will appear in one location, then milliseconds later, it’ll be distorted to a different spot.

We see this as twinkling.

So why do stars appear to twinkle, while planets don’t?

Stars appear as a single point in the sky, because of the great distance between us and them. This single point can be highly affected by atmospheric turbulence. Planets, being much closer, appear as disks.

We can’t resolve them as disks with our eyes, but it still averages out as a more stable light in the sky.

Astronomers battle atmospheric turbulence in two ways:

First, they try to get above it. The Hubble Space Telescope is powerful because it’s outside the atmosphere. The mirror is actually a quarter the size of a large ground-based observatory, but without atmospheric distortion, Hubble can resolve galaxies billions of light-years away. The longer it looks, the more light it gathers.

Second, they try to compensate for it.

Some of the most sophisticated telescopes on Earth use adaptive optics, which distorts the mirror of the telescope many times a second to compensate for the turbulence in the atmosphere.

Astronomers project a powerful laser into the sky, creating an artificial star within their viewing area. Since they know what the artificial star should look like, they distort the telescope’s mirror with pistons canceling out the atmospheric distortion. While it’s not as good as actually launching a telescope into space, it’s much, much cheaper.

Now you know why stars twinkle, why planets don’t seem to twinkle as much, and how you can make all of them stop.

Universe Today has written many articles about stars. Here’s an article that talks about a technique astronomers use to minimize the twinkle of the Earth’s atmosphere.

If you’d like more information on stars, check out Hubblesite’s news releases about stars, and here’s the stars and galaxies homepage.

We have recorded several episodes of Astronomy Cast about stars. Here are two that you might find helpful: Episode 12: Where Do Baby Stars Come From, and Episode 13: Where Do Stars Go When they Die?

This article was republished with permission from Universe Today.

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For Political Candidates, All Twitter Publicity Is Good Publicity

More mentions on Twitter mean more votes for a candidate, whether the buzz is positive or negative.
Tweeting To Vote Screenshot via Twitter

Good news, Anthony Weiner? New research suggests that the more social media posts about a political figure, the greater the number of votes the candidate will get at the polls.

In politics, all Twitter publicity is good publicity, according to a study presented today at the American Sociological Association's annual meeting. The percentage of tweets mentioning Congressional candidates in 2010 and 2012 races correlated positively with the percentage of votes those candidates received, the researchers from Indiana University Bloomington found.

More Tweets, More Votes:  DiGrazia et. al

They analyzed 537 million tweets collected by IU's Center for Complex Networks and Systems Research, which has the largest sample of tweets in the world compiled for academic study, and found that more mentions of any kind on Twitter (either lauding or bashing the candidate) meant more votes, possibly because stronger candidates attract attention from both sides. "Specifically, individuals may be more likely to attack or discuss disliked candidates who are perceived as being strong or as having a high likelihood of winning," the researchers write. In other words, you tweet about the candidates that you think could win, whether that prospect delights or terrifies you. (How tweets about a candidate's really weird personal life play into this they do not say, though.)

The study determined that social media can be a reliable source of data about political behavior.

"Think of this as a measurement of buzz," one of the study's authors, sociologist Fabio Rojas, said in a press statement. "Even if you don't like somebody, you would only talk about them [SIC] if they're important."

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FYI: How Often Do Astronauts Do Laundry?

The European Space Agency (ESA) has gotten to the bottom of the most pertinent question we hadn't been asking. Are all astronauts floating around in dirty underoos?

The ESA's video team polled people in various European cities to find out what the common Earthling thinks is going on under those spacesuits. Some apparently think astronauts get paper underwear, while others think a lack of gravity means the grime just floats away in what must be a kind of Pig-Pen-esque cloud. If only!

The answer is, astronauts don't do laundry at all. Though NASA commissioned a washing machine for the International Space Station in 2011, apparently, astronauts' dreams of freshly laundered linens have yet to materialize. Water is a precious commodity on the ISS, and no one wants to waste precious recycled urine on dirty socks.

Fresh clothes are delivered from Earth like any other supplies. But since that doesn't happen that often (and launching anything into space is waaay expensive), astronauts usually have to wear their clothes--and underwear--for much longer than they would on Earth. Since astronauts start to lose their sense of smell in space, it's probably not that bad. Astronaut Don Pettit once wrote that he changed his underwear once every three or four days on the ISS--and that he had been wearing the same pair of shorts for months.

And here's a perk: When you're an astronaut, your dirty laundry is literally just incinerated. Waste and dirty linens from the Space Station burn up on re-entry to the Earth's atmosphere! Ah, what a life.

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TV Footage Shows Some Of The First Polio Shots Given In The U.S.

A recently digitized TV news archive highlights the big points of the 1950s and 1960s: Civil Rights and the polio vaccine.
School Polio Shot, 1955 A boy grimaces as he receives one of the first polio shots ever dispensed in Roanoke, Virginia. WSLS-TV footage archived by the University of Virginia Library

In 1955, days after officials introduced the "new, wonder vaccine" against polio to Roanoke, Virginia, local news station WSLS-TV asked some parents in the street about it. Of the four adults they interviewed, three said they planned to get their children vaccinated. "I do think it's a worthwhile project and I hope it's going to be a success," one woman said.

Another woman, however, seemed a bit more skeptical—a sentiment that some modern parents might recognize. "I think I shall wait until I see some of the results from the other children," she said.

That old footage is now available online, thanks to a new project by the University of Virginia Library. In 2010, the National Endowment for the Humanities gave the library a little more than a quarter of a million dollars to preserve and make digital copies of WSLS-TV broadcasts dating from 1951 to 1971, along with printed anchors' scripts. The library released the archive this week.

You can keyword search the archive, but the library has highlighted some of the coolest stuff. There are reports on the desegregation of local schools and the Civil Rights movement. And there's a page dedicated to the introduction of the polio vaccine to Roanoke, which served as a distribution center for the shot for most southwestern Virginia counties. The development of a successful polio vaccine was big news throughout the U.S.

Anchor Script for a 1955 Polio Vaccine News Spot:  WSLS-TV, archived by the University of Virginia Library

Interestingly, the archive shows that at the beginning, scientists didn't know everything about the vaccine they were giving out. A decade after the first Roanokans received shots, a 1965 WSLS-TV broadcast carried the city health commissioner's call for locals to begin or finish their immunization program. Re-immunization was important, he said, "because the length of time a person is protected by either [the Salk or Sabin forms of the vaccine], is still a matter of conjecture." The U.S. Centers for Disease Control and Prevention now recommend three or four shots for lifetime protection against polio.

[University of Virginia Library]

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A Cloud Room And Other Amazing Images From This Week

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