Friday, November 29, 2013

Flashmob for Science (save the date!)

We will hold our next "Flashmob for Science" in Berlin on the evening of February 20, 2014.  Two related conferences will be taking place in Berlin on that day, so they could potentially help make the event really large.

The location and time will be announced later to the date of the Flashmob. If you would like to get email updates about the flashmob, send me an email with the subject "BERLIN FLASHMOB SIGNUP":
my email
Our first Flashmob for Science was a lot of fun! I hope that the weather will cooperate on February 20, and that I'll see you there!

Was ist ein Flashmob für die Wissenschaft? Clicken Sie hier.

Sunday, November 24, 2013

Another problem with kids screen time, and the one app that can solve it

Most apps keep you up at night, but f.lux helps you sleep

Light is the most important signal your body uses to know when to go to sleep and when to wake up. When it's dark at night, your brain produces a hormone called melatonin. Melatonin helps make you sleepy, and also helps fight against some cancers. When you are exposed to bright blue light at night, your brain can't make the hormone, and that can make it take longer for you to fall asleep. Sleep is essential to health, so anything that keeps people up at night is a public health concern.

Most of us use computers, tablets, and smartphones at night, exposing ourselves to the bright, blue light that keeps people awake. A very clever free program called f.lux has been developed to hopefully help reduce this problem, by cutting the amount of blue light we are exposed to at night. At sunset, f.lux changes the white balance of your screen, so for a minute or so everything seems orange:

f.lux works by reducing the amount of blue light your screen emits

But your brain is designed to adjust to changes in color throughout the day, so you very quickly get accustomed to the warmer light. In fact, if you switch back to the standard setting, then everything will at first appear to be weirdly blue:

After a few moments, the f.lux screen will look "white" and
if you switch back the standard setting will now look cold

By installing the program, you will reduce your exposure to blue light at night. That might help you sleep better, and could potentially improve your long-term health. It's free, so you should install it on your computer, tablet, and smartphone right now!

If you're a first time visitor, this blog is about the Loss of the Night app and citizen science project. In brief, we need people living big cities to tell us how many stars they can see (no stargazing experience necessary). But the blog also occasionally has other stuff related to light at night, for example photos of good and bad street lighting from around the world, and this calendar of moon phases for 2014.

Additional notes:

1) I am not aware of any study that examines to what extent f.lux reduces the melatonin suppression caused by looking at a screen. It's basically a band-aid for the societal problem of improper light exposure. If you really want to sleep better and live longer, spend as much time as possible outside during the daytime (even if it's cloudy), and avoid bright white lights at night.

2) Some tasks (such as editing the color balance of a photo) should probably not be done with f.lux turned on. You can temporarily disable f.lux for one hour with just two clicks.

3) I have nothing to do with f.lux, and I don't know the people who created it. But I study light at night, and I am just doing my part to spread the word about this great program.

4) Have friends that have trouble going to bed at night? Tell them about f.lux!

Wednesday, November 20, 2013

Moon phase calendar for 2014

Loss of the Night app user Andrew Cool from Australia has produced this very cool calendar of the phases of the moon in 2014:

A higher resolution version is available here, and you can buy the poster on zazzle. (I got a coffee mug, and I don't recommend it because Zazzle's printing resolution on the cup is too low.)

Update: Andrew has made 2015 moon phase calendars with different designs and for the Northern and Southern hemispheres.

If this is your first-ever visit to the blog, welcome! The blog is about a citizen science app called "Loss of the Night". We need your help to understand how changes in street lighting technology are changing the night sky. You can read our introduction to the blog here, and instructions on how to use the app here.

There's lots more to see, including:
You can see bring up our entire photo series via this link, and all of our posts about the moon here. Thanks for visiting!

Friday, November 15, 2013

A step by step guide to using the Loss of the Night app

Note: This guide is for an outdated version of the app (v1.0.2). Here are the new directions for Android and iOS.

Friday, November 8, 2013

View from your App

Paul Marchant is a chartered statistician from Leeds, England, who is investigating whether or not brighter street lights improve traffic safety or reduce crime. He showed this image of a burned out car directly beneath a streetlight during his talk at the recent international conference on Artificial Light at Night.

Burned out car under streetlamp by Paul Marchant is licensed under a
Creative Commons Attribution-NonCommercial 3.0 Unported License.

The point of the photo is that lighting by itself can't prevent crime, and simply making lights brighter is not a very effective way to try to reduce crime. So far, Dr. Marchant has observed that changes of lighting in London have not had a measurable impact on crime rates. He worries that earlier studies showing effects due to change in lighting have been affected by similar problems to many medical studies. This includes publication bias (researchers are more likely to publish exciting results) and statistical errors (e.g. crime and fatal traffic accidents have been falling for years in many countries, so regardless of what the intervention is, you could incorrectlly see it as "causing" a drop in crime).

Thursday, November 7, 2013

A (nonscientific) survey of twitter users (updated)

It is estimated that about 20% of people worldwide can't see the Milky Way from where they live, and it's therefore believed that many young people have never seen the Milky Way in their life. Since lots of young people use twitter, let's see what twitter users tell us!

If you use twitter, then click the retweet button that applies to you below.

Never seen the Milky Way:

Have seen the Milky Way:

Please note that this is most certainly not a scientific survey! If the tweets go viral, I think it will be interesting to see the results nonetheless.

Update 2013/11/11: So far, only 3 of 40 respondents (7.5%) say they have never seen the Milky Way.

First time blog visitors: This blog is about apps that are used to figure out how bright the sky is. You can read about the apps here.

Saturday, November 2, 2013

Looking for stars in Berlin

Last week we hosted the first ever international conference on artificial light at night, ALAN 2013! After two evening events of the conference, I took advantage of being out on a night with clear skies to use the Loss of the Night app in three places. I've labelled their approximate locations on this map of Berlin at Night from the Suomi-NPP VIIRS image:

The first location, "Dahlem" is in a suburb at the edge of Berlin. The second, "Spreebogen" is an unlit park across the river from the brightly lit main train station. The third was a block away from Friedrichstraße, which is the brightest place in the center of the city (at least according to VIIRS). The results of the three measurements are shown below:

The plots are similar to the ones I showed in an earlier blog post. The vertical axis shows how bright or faint the stars are. Stars I said I couldn't see are shown in red, stars I wasn't sure about are shown in blue, and stars that I said I could see are shown in black. The horizontal axis shows the time since the measurements were started (each small tick is one minute).

The horizontal lines show the estimate (maximum likelihood fit) of how bright the sky was at each location. With a few assumptions, it's possible to turn this value into a very rough estimate of how many stars you can see. In Dahlem, about 300 stars could be seen with that level of skyglow, in Spreebogenpark about 200, and near Friedrichstraße around 100. By comparing the three datasets you can see that the app is really working, and that in each location my results are quite self-consistent. Unfortunately, I didn't happen to have an SQM with me to check how closely these results compared to the actual sky radiance.

I am continuing to learn a lot about the stars and constellations by using the app!  Since September I now know learned the stars Vega and Deneb and the constellation Cygnus (the swan) very well.  I am also slowly getting used to Perseus. I think that all of the stars I wasn't sure about were in the (very sparse) constellation Draco.