Is daylight savings time really saving us a headache?

All together now, let's turn our clocks back an hour tonight. Daylight savings time (DST) ends tonight at 2am and we all celebrate because we get another hour of sleep. But should we be celebrating DST in general? Perhaps not.

(Image Credit: Andy Woodruff)

(Image Credit: Andy Woodruff)

Before we delve into the pros and (mostly cons) of DST I wanted to talk a little about the history of the topic on hand.

DST was first used in the US following various "real and imagined" petroleum shortages following various wars in the middle east in the 1970s. In other words, it was not invented for the farmers to have an extra hour of daylight in the morning. I have no idea where that myth came from. Also, the 1970s was very recent. I always imagined that DST has been around forever, or at least since before WWII. Also note that most of the world does NOT use DST.

The basic problem with DST is that it seems like lawmakers do not fully understands the benefits and drawbacks of this idea. This makes sense because DST is used to combat changing seasons, so it's a complicated issue that differs based upon where you are on Earth. So let's break this down further.

Fundamentally, DST begins in March and ends in November, which means we're back to normal time after tonight. In March, we spring the clocks forward one hour and effectively less sunlight in the morning and more sunlight in the evening. Then in November, when we turn our clocks back an hour, we experience more sunlight in the morning and less in the evening.

What are the effects of having more/less sunlight in the morning/evening?

[Keep in mind that these effects were not the main cause of the implementation of DST, the perceived shortage of petroleum was, so DST was implemented to helps save on energy usage. However, it's also been shown that energy usage doesn't change in a statistically significant way with the use of DST.]

It turns out that having or not having an extra hour of sunlight in the morning or in the evening has really interesting statistical effects on things like crime, sleep cycles, car crashes, school children, farmers, or shopping.

It turns out farmers DO NOT BENEFIT from DST like we were all somehow led to believe. In fact, they can't start working earlier just because the clock moves around. The sun is on its own schedule and grain farmers must wait for the dew to dry. Additionally, cows apparently don't wear watches and really don't appreciate being milked at odd times.

It turns out that waking up without sunlight (which is what DST will mess with tomorrow) is really hard for people and can make life tough. 

It turns out that there are less burglaries when it is brighter in the evening.

It turns out if you're tired, there's statistically more likely to get in a car accident the morning/ week after DST in spring when you get slightly less sleep. 

It turns out that people do more shopping and give the economy an extra boost when there's more daylight in the evening after work.

So there are many negatives and positives to having an extra hour of sleep in the morning or evening. But what does DST actually do to change these hours of light?

Let's look at some maps of the theoretical US if we were on permanent DST or just on permanent standard time (no DST):

dst_always.png

(Image Credit: Andy Woodruff).

(Image Credit: Andy Woodruff)

(Image Credit: Andy Woodruff)

Here's the great thing: Humans get to choose which plot we prefer. Keep in mind that there are pluses and minuses to each one. I prefer the scenario with permanent DST because I really enjoy running in sunlight after work. But to each their own.

Here's the not great thing: somebody higher up in government gets to choose your map for you.

Russia did this for its citizens and went to permanent DST in 2011. However, since everyone was upset with having no light in the morning, they switched back to no DST and plan to stay there forever. The kickback from the Russian people was enough to change the time zone of the entire country!

So let it be known - your opinion can be heard, so get educated on what's going on with DST!

 

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"That's no moon, it's a rogue planet"

An artist's conception of a free floating planet without a host star. Note that this is a Jupiter-sized giant planet, which are far less likely to be orphaned in interstellar space. (Image Credit: NASA/JPL-Caltech)

An artist's conception of a free floating planet without a host star. Note that this is a Jupiter-sized giant planet, which are far less likely to be orphaned in interstellar space. (Image Credit: NASA/JPL-Caltech)

We have eight planets in our solar system (let's save Pluto for a another time). But what if I told you there might have been even more early on in the formation of our solar system? And that now these planets are orphaned in interstellar space.

In October, at the Division for Planetary Sciences (DPS) meeting in Pasadena, astronomers announced that there may be as many as seven or eight orphaned Mars-sized planets per star. 

Thomas Barclay and Elise Quintana at the NASA Ames Research Center ran dynamical simulations of a solar system. First, they ran the simulation without gas giants like Saturn or Jupiter. Then, they introduced a couple of gas giants. There were a results. First, gas giants act as big bullies. When gas giants are present, more material gets dynamically disturbed and flung out of the system. Second, they found that there's a mass limit to which types of planets are ejected from the system. Surprisingly, planets larger than Mars seldom escape.

The gas giants left to right: Jupiter, Uranus, Saturn, and Neptune are the big bullies of the solar system. This becomes especially apparent when stacked up side by side to scale. (Image Credit: Wikipedia Creative Commons, Lmspascal)

The gas giants left to right: Jupiter, Uranus, Saturn, and Neptune are the big bullies of the solar system. This becomes especially apparent when stacked up side by side to scale. (Image Credit: Wikipedia Creative Commons, Lmspascal)

In the past, astronomers have mostly found gas giants in interstellar space. It now appears that this may be an observational bias. In other words, our instruments are better and finding bigger things (makes sense). For instance, we found the alphabet soup planet 2MASS J1119-1137 95 light years away in the constellation Hydra which is 4-8 Jupiter masses. It's huge!

But now theory has proposed a new model. How do we look for these smaller Mars-sized outcasts? With the Wide Field Infrared Survey Telescope (WFIRST), which will launch in the 2020s. Infrared surveys are really good at finding warm small planets in the cold expanse of space.

This telescope will help us determine if there are truly more rogue planets in this galaxy than stars. So stay tuned - the future of science is now!

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The Martian Curse

Mars is not nice. It's not a fun, easy place to insert a satellite into orbit or to land a lander.

53% of missions to Mars have ended in failure, whether it be a failure to launch, a failure en route, or a failure to orbit and/or land.

This Wednesday, the ESA's Schiaparelli probe crash landed on Mars when its parachute released a minute too early. So this week I'd like to explore some of the more epic failures and why it's so hard for people to send robots, let alone people, to the red planet.

The Mars Reconnaissance Orbiter confirms using before and after shots that the Schiaparelli lander died a horrible death. The white speck is the parachute and the black dot is the impact crater from the crashed lander. (Image Credit: NASA/JPL-Caltech/MSSS)

The Mars Reconnaissance Orbiter confirms using before and after shots that the Schiaparelli lander died a horrible death. The white speck is the parachute and the black dot is the impact crater from the crashed lander. (Image Credit: NASA/JPL-Caltech/MSSS)

Let's first go through a brief timeline of failure (with a few success stories). I've color-coded things where orange is a 'sorta' success and green is a successful mission. You can see that from the 60s to the end of the 90s there were few successes...

And onward to the next century, where the outlook get a little greener.

Overall, the missions that didn't work often failed to launch, insert into orbit correctly, or land gently. Going to Mars is especially challenging due to a few special factors including the length of the mission (it takes a few years and a lot of fuel to even arrive at Mars) and the demands of a delay in light travel time to communicate with the probes. In other words, you cannot rely upon real-time corrections to fix glitches in the computers. Therefore, the orbiters often fail to arrive at Mars due to computer or software problems that occurred during the extra-long journey. These glitches either shut down communication or resulted in an altered trajectory that cannot be corrected.

Only four space agencies have successfully sent a mission to Mars (NASA=USA, Soviet and RSA=Russia, ISRO=India, and the ESA=European). 

If missions make it to Mars, it is often difficult for orbiters to insert into the atmosphere and landers to navigate the challenging and dynamic atmosphere during their descent. Therefore, the landings are seldom soft because they require a multi-stage descent to slow the lander. Unlike on Earth, you cannot rely upon a thick atmosphere to slow your fall and must often do fancy things like a sky crane (Curiosity landed this way).

An artist's conception of the landing of Curiosity using a detachable sky crane. (Image Credit: NASA/JPL-Caltech)

An artist's conception of the landing of Curiosity using a detachable sky crane. (Image Credit: NASA/JPL-Caltech)

And then, even when the landers succeed, Mars' intense seasons, polar winters, dust storms, and winds can kill the rovers that have successfully landed on the surface. For instance, Spirit's solar panels eventually got buried by dust and the Phoenix lander froze to death in winter.

However, despite all the failures of the past, we're learning. We've learned to use metric units when building a spacecraft. We've learned how to launch long-range missions. We've learned how to use fancy technology to land on the surface of a planet with little atmosphere. 

The real question is: How long before we're confident enough to send humans to the red planet? This will involve a whole series of new challenges and I can't help but wonder if we are able to face the daunting 53% failure rate to achieve this goal.

 

 

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The universe just got crowded

This week the number of known galaxies in the universe just increased by a factor of 10! Let's dig into this news.

First off, this is the Hubble Ultra-Deep Field that astronomers previously used to estimate the number of galaxies in the universe:

The Hubble Ultra-Deep Field consists of a combination of images from ultra-violet to infrared light taken over a nine-year period of time. There are 10,000 galaxies in this image. The oldest of which is only a couple of million years younger than the age of the universe. For context, the universe is 13.8 billion years old. (Image Credit: NASA, ESA, H. Teplitz and M. Rafelski, A. Koekemoer, R. Windhorst, Z. Levay)

The Hubble Ultra-Deep Field consists of a combination of images from ultra-violet to infrared light taken over a nine-year period of time. There are 10,000 galaxies in this image. The oldest of which is only a couple of million years younger than the age of the universe. For context, the universe is 13.8 billion years old. (Image Credit: NASA, ESA, H. Teplitz and M. Rafelski, A. Koekemoer, R. Windhorst, Z. Levay)

The goal of the Hubble Ultra-Deep Field (HUDF) was to observe the earliest and farthest away galaxies in the universe. It did this job extremely well.

To understand what astronomers were trying to do with the HUDF, we have to understand how age and distance work with galaxies in our universe. Because of the finite speed of light, the farther away you look, the farther back in time you are looking. In other words, you are seeing earlier times in the universe because the light has taken so long to travel to us from those distant galaxies. It's a cool way to achieve time travel.

Astronomers are always trying to find the oldest galaxies and to do this they have to look as far away as possible. But, the farther away you try to look, the fainter the light becomes because light travels in straight lines and so the total brightness falls off with distance. Overall, it's extremely challenging to observe very old galaxies (in other words the earliest ones that formed in the universe) because not only are they far away, they are also intrinsically fainter.

But let's return to the HUDF. From the HUDF observations, astronomers learned that the oldest galaxies are undergoing extremely rapid star formation. They also got a large enough sample of very old galaxies to understand that galaxies in the early universe are messy. They are in the stages of evolution where they are merging together. They are baby Milky Ways on their way to becoming larger and more ordered like the beautiful spiral galaxies we're used to seeing in the local universe (local=nearby in space and time).

A recreation of the cosmic web, which is composed of galaxies, clusters of galaxies, and dark matter in filaments (blue stuff) and the empty voids in between (dark). (Image Credit: NASA, ESA, E. Hallman)

A recreation of the cosmic web, which is composed of galaxies, clusters of galaxies, and dark matter in filaments (blue stuff) and the empty voids in between (dark). (Image Credit: NASA, ESA, E. Hallman)

But, here's the kicker. The HUDF also allowed astronomers to count the number of galaxies in the universe. They estimated that there were ~100 billion galaxies in the universe.

A week ago, another group of astronomers found that there are 2 trillion galaxies in the universe. Using a technique which uses the measured densities of galaxies in the universe, they found that there are many smaller galaxies that are unaccounted for in the Hubble images. These galaxies are too faint to observe with the HUDF but incredibly important for describing the population of very very old galaxies. 

Think about this for a second. There are 10 times the number of galaxies in the universe than we previously thought. The sheer scale of astronomy already blows my mind, but this week astronomers proved that there is still so much to learn!

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Are we living in the Matrix?

(Image Credit: Hersson Piratoba)

(Image Credit: Hersson Piratoba)

According to a recent interview in the New Yorker, Simulation theory has caught on with tech billionaires in Silicon Valley. Elon Musk, founder of SpaceX, Tesla, Paypal, and soon to be grand dictator of Mars, said in June that there's a one in a billion chance that we're not living in a computer simulation. So to recap, that's a billion to one chance that we are in a simulation.

His logic is that if simulating reality were possible (I think it's implied we're talking about some highly advanced alien civilization here, not humans), it's highly likely that there are billions of simulations running in parallel. And since we have no way of telling if we're in a simulation or not, this means that our chances of being in the one version of reality amongst those billions of other simulations are very small indeed.

Also according to the same New Yorker interview, two unnamed tech billionaires are paying scientists to try to break us out of the Matrix. Since there are some very rich and powerful people interested in Simulation theory, I'd like to examine it more closely through a scientific lens.

Science: The intellectual and practical activity encompassing the systematic study of the structure and behavior of the physical and natural world through observation and experiment

Let's define science ------------------------------>

The key words in this definition are observation and experiment. For something to be classified as science, it must be testable. This is why things such as astrology, scientific racism, cryptozoology, the flat earth society, climate change deniers, etc, are not considered scientific - they simply are not testable.

Even some areas traditionally thought of as scientific do not follow this definition. For example, my favorite 'science' topic bordering on pseudoscience is string theory. String theory is a mathematical construct that the universe is made out of tiny vibrating things - it leads to cool predictions like 11-dimensional space and alternate universes. However, there is no way to test it.

I'm an observer. I'd like to talk about some testable predictions of Simulation theory.

  1. It might be possible to observe little glitches in the system. Think of the déjà vu scene in the Matrix where Neo sees the same black cat walking by twice. However, this seems unlikely given the sophistication it takes to simulate billions of people and the physics engine to accompany them. A philosopher who has done a bunch of thinking about Simulation theory, Nick Bostrom, stipulated that it might be possible to detect glitches in the system if they are plopped right into our laps. He said that a window could potentially pop up saying: "You are living in a simulation. Click here for more information."
  2. Another interesting way to investigate this theory scientifically would be to create simulated consciousness for ourselves. To date, while we have been able to do impressive things with computers, the AI we create is not fully conscious (think Skynet). Developing AI to investigate if a simulated universe is possible would fall under the category of experimentation.

However, even though the observations and experiments listed above may help to investigate this theory, Simulated reality by definition may be impossible to prove. At this point, my brain is really starting to hurt. 

It turns out that experimenting or making observations in a simulated reality may be part of a nested simulation. This means that we may not be able to trust anything we observe in our 'reality' because it could be part of a separate simulation. Bummer. 

So what do I believe and where can I leave off this discussion after making everyone thoroughly freaked out? My scientific brain tells me that this theory is not fully testable. So while it's a fun thought experiment to play around with, I'm not prescribing to Simulation theory. But trust me, I'll be keeping my eyes peeled for glitches for at least the next week!

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Less than 1% of Nobel prizes in physics are awarded to women - Houston, we have a problem

(Image Credit: Public Domain)

(Image Credit: Public Domain)

This is the Nobel prize, one of the most prestigious international awards. There are five Nobel prize categories (Peace, Chemistry, Physics, Physiology and Medicine, and Literature); today we're going to talk about physics. 

This week, the Nobel committee announced the recipients of the Nobel prize in physics for 2016. Three British physicists had successfully investigated 'exotic phases of matter'. I got excited wondering if any of these brilliant physicists are women. I like it when bad-ass women do excellent science. But, much to my chagrin, and not really to my surprise, I quickly found out they are all men.

Marie Curie 1903 (Image Credit: Nobel Foundation)

Marie Curie 1903 (Image Credit: Nobel Foundation)

*This article will focus on gender, although there are definitely other problems with race, age, etc with the awards

I don't mean this post to at all belittle their work or the accomplishments of any of the physics Nobel prize recipients. They are all excellent scientists. Instead, I'd like to take some time to address something that's very personal to me as a woman in astronomy: Where are my role models?

It's the 21st century. The Nobel prize in physics has been awarded to exactly 204 people since 1901. 2 of those people were women*. 2/204 is LESS THAN 1%. 

The last Nobel prize in physics awarded to a woman was Maria Goeppert Mayer in 1963 for "discoveries concerning nuclear shell structure" and before that .... go all the way back to 1903 to Marie Curie for "joint researches on the radiation phenomena". 

Marie Curie almost didn't even get the Nobel prize. The committee was planning on awarding the prize to only Pierre, her husband, and Henri Becquerel (he discovered radiation). However, luckily one of the committee members was an advocate for women in science and was able to notify Pierre who protested strongly. 

So what's the problem? According to the American Physical Society, 20% of individuals at the bachelor, doctorate, and postdoctoral level in physics are women. So shouldn't 20% of prizes in recent years be going to women researchers?

Part of the problem may be unconscious or conscious bias. Most Nobel prizes for all categories go to men and most often people of European descent. Part of this bias may originate in the fact that the awarding committee is composed of five people nominated by the Norwegian parliament. Nominations are also made by prominent scientists worldwide, so there may be some bias here.

Part of the problem may be the award structure. Currently, the physics award can be shared by three people maximum so these awards tend to go to leaders of large research groups. The entire group contributed to the achievement but only the leaders receive the recognition. In physics, the oldest and most prestigious faculty and research group leaders are almost entirely men (far lower than the 20% APS statistic I presented above). 

Part of the problem may be a lack of transparency. The Nobel committee keeps their decisions secret for 50 years following the announcement of the award. So we have no idea if women were looked over in the 1970s and 80s. And 90s. And 2000s. And 2010s.

It might be time to right past wrongs. We do know that in 1974, the prize was awarded to Antony Hewish and Martin Ryle for their discovery of pulsars. However, Jocelyn Bell made the actual discovery from looking through the radio data. She was not included in the prize, which was instead awarded to her advisor.

Vera Rubin discovered that a vast amount of previously undetected dark matter in galaxies caused them to rotate faster than previously expected. (Image Credit: Stefania.deluca, Wikipedia Public Domain)

Vera Rubin discovered that a vast amount of previously undetected dark matter in galaxies caused them to rotate faster than previously expected. (Image Credit: Stefania.deluca, Wikipedia Public Domain)

Another astronomer who was perhaps passed over (we don't know as of now if she was nominated) is Vera Rubin. There's a hashtag floating around, #NobelforVeraRubin, which advocates for the recognition of her discovery of dark matter. Dark matter spawned entire fields of astronomy and physics, yet Rubin never received a prize. Rubin is 88 and prizes cannot be awarded posthumously, so sadly it might be getting too late for her.

So how do we proceed? Hopefully, we can change the way it is awarded, increase transparency in the process, and right past wrongs. Awards in science should reflect the people who are doing the science and not ugly stereotypes and biases that we're trying to eliminate from the scientific community.

 

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Do tides trigger earthquakes? Possibly another reason to respect the moon

Tsunamis - a devastating effect of an earthquake. Although there are some tsunami warning systems and seismologists can sometimes predict when earthquakes will occur, tsunamis continue to catch us off guard (see below, the Tohaku earthquake and tsunami in Japan). Scientists are continually looking for better ways to predict earthquakes around the world. Turns out they might be able to use the phases of the moon.

(Image Credit: U.S. Navy photo by Petty Officer 3rd Class Kevin B. Gray) 

(Image Credit: U.S. Navy photo by Petty Officer 3rd Class Kevin B. Gray) 

Last year, a paper in the journal Physics and Chemistry of the Earth suggested that the moon may be responsible for triggering earthquakes. As I looked through this paper, I though to myself, "now this is interesting, but do I believe it?" The answer is I don't know. So I'd like to take this opportunity to walk through this study using a critical lens.

Syzygy:
noun ASTRONOMY
a conjunction or opposition, especially of the moon with the sun

Why did I immediately jump onto the critical train? This topic of astronomical syzygy in conjunction with earthquakes was immensely popular back in the 1800s. By the way, syzygy is used here to talk about the idea that scientists thought when the Earth, Moon, and Sun were all aligned (for instance, in that order during new moon), the tidal forces should be strongest, causing earthquakes and other phenomenon to happen. Scientists were obsessed but were never able to find a definitive link between earthquakes and the phases of the moon. So what has changed?

The Hellenic subduction zone in Greece. (Image Credit: Wikimedia Commons, Mikenorton)

The Hellenic subduction zone in Greece. (Image Credit: Wikimedia Commons, Mikenorton)

The scientists studied earthquakes along the Hellenic Arc fault in Greece and found a correlation between the frequency of earthquakes and the tidal lunar monthly variations. 

On interesting argument in the paper is that while the tidal stresses are much less than stress from the earthquake itself, the tidal stresses are actually comparable to or greater than the tectonic stress accumulation in a fault that precedes an earthquake.

But what is the amount of force that a syzygy can actually exert on the Earth? And how does it exert this force? 

A tide schematic of the tidal effects of the Moon on the Earth with force vectors. (Image Credit: Wikimedia Commons)

A tide schematic of the tidal effects of the Moon on the Earth with force vectors. (Image Credit: Wikimedia Commons)

Let's say the alignment is Earth, Moon, and Sun. The Sun is much more massive than the moon, but it exerts a very small force on the Earth because it is very far away and you'll remember that Newton told us that gravitational force decreases with the square of distance. So although the moon is smaller, it has a bigger effect. However, this doesn't mean we can just ignore the Sun altogether. In fact, this study out of Greece found that one of the time periods of greatest correlation was when all three celestial bodies were lined up.

Okay, so the moon is pulling on water on the Earth's surface, which causes high tide on the side of the Earth towards the moon. But why is there high tide on the opposite side? The Earth is actually being pulled away from the water! There's a way to explain this with vectors, but a good way to think about it is that the water on the far side is experiencing slightly less pull than the crust on the far side because it's slightly farther away. Low tides happen where there is no pull from the moon or pulling away by the body of the Earth because the water is occupied elsewhere. 

So with our new understanding of tides, I'd like to return to the study at hand. Why haven't there been correlations found for all types of earthquakes that occur all over the earth? It turns out that although the force of the moon is also pulling on the crust it may have the biggest effect on the oceans. So during high tide, as water piles up, the weight of the water may stress underwater faults more so than land faults, leading to the discovery of this correlation appearing over an underwater fault zone. Also, like I said earlier, the force from tides may be similar to that of building up stresses in the fault already, so the tides may act as the final straw that broke the camel's back. Perhaps the fault stresses don't always need this extra push.

Regardless, the studies that have been finding correlations are all relatively new, so while it's an exciting idea that we might be able to use the forces of the moon to predict when certain earthquakes may occur, there's still much to be learned on this topic.

 

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Peeking through the Veil: An exploration of astronomical images

They say a picture is worth 1000 words. But sometimes you need 1000 words to describe a picture. Astronomical images often beg more explanation and so today I'd like to do them justice by taking us on a journey through a famous nebula - the Veil:

(Image Credit: Ken Crawford, Wikimedia Commons)

(Image Credit: Ken Crawford, Wikimedia Commons)

Wow, this image is gorgeous.

Before I dive into the picture above I'd like to take a step back and put this image in context. This nebula is part of a much larger structure called the Cygnus Loop. The Cygnus Loop is a supernova remnant from a star that exploded probably somewhere between 5000-8000 years ago. It takes up an area on the sky equivalent to 36 full moons! If you happened to be alive at the time, this supernova would definitely have been visible from Earth.

An ultraviolet image of the Cygnus Loop taken by NASA's Galaxy Evolution Explorer. The Veil nebula is NGC 6960, which is part of the Western Veil. (Image Credit: NASA/JPL-Caltech)

An ultraviolet image of the Cygnus Loop taken by NASA's Galaxy Evolution Explorer. The Veil nebula is NGC 6960, which is part of the Western Veil. (Image Credit: NASA/JPL-Caltech)

Whoa, wait a minute. If this thing is 36 times the area of the full moon, why don't we get a lovely view of it at night? The short answer is that these images are composite images that are captured by telescopes that put the human eye to shame.

The blue image with the labels above is an ultraviolet images. Humans can only see visible light, so this telescope is capturing very faint emission with a long exposure time that humans could never hope to see because our eyeballs don't have access to this part of the electromagnetic spectrum. 

The second ionized transition of oxygen, or OIII occurs at an energy associated with the wavelength 5007 Angstroms, or 500 nanometers. (Image Credit: Academo)

The second ionized transition of oxygen, or OIII occurs at an energy associated with the wavelength 5007 Angstroms, or 500 nanometers. (Image Credit: Academo)

The first image up top with the lovely pink color is a color-composite RBG image that has been processed to highlight some very interesting features of the nebula. The pink color is representative of a very narrow filter type of exposure that tracks a specific emission feature known as H alpha, or Hydrogen alpha. The teal tracks my favorite emission feature, Oxygen III, or OIII for short. While these emission features are very interesting to astronomers because of the processes they track in nebulae, they also make for a beautiful image. 

H alpha is a red color at 656 nanometers.

H alpha is a red color at 656 nanometers.

What color are these transitions? OIII is a green color and H alpha is red (look to the left). So in astronomical images, astronomers usually attempt to keep these transitions closely related to their true colors. But while these transitions are actually visible to the human eye, we wouldn't be able to see them looking up at the sky.

 

This image is created by combining a cumulative 36 hours of exposures. This telescope also has superior light collecting ability. The amount of light a telescope can capture is related to the area of the mirror. Put this way, you can see why the human eye falls short. But this is why we build telescopes, right?

 

 

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The Earth is Changing on Human Timescales

Earth's atmosphere from the International Space Station. (Image Credit: NASA Image of the Day)

Earth's atmosphere from the International Space Station. (Image Credit: NASA Image of the Day)

We know so little about Earth.

There's an expression floating around out there that we know less about the ocean floor than we know about the moon. This is true if you're talking about high resolution maps of the ocean floor as compared to high resolution maps of the moon surface.

Something that has been bothering me a lot lately is how little we know about Earth's climate and how the oceans, land, ice, weather, and atmosphere interact. I'm not here to diss climate scientists; in fact, kudos to them for embarking on a journey to explore a complicated interconnected web of Earth systems. 

No. Instead, I'm talking about everything I've been learning about the effects climate change. Our world is changing in ways that we couldn't have predicted. In fact, climate change is making some areas warmer, some colder, some wetter, some drier, some stormier, and some calmer in a complicated web of cause and effect.

Here is a chart from the National Oceanic and Atmospheric Administration (NOAA) on some climate anomalies from August 2016:

(Image Credit: NOAA)

(Image Credit: NOAA)

I'd like to take some time to focus on some of the surprising results of climate change that we see here. It turns out that climate change doesn't always imply global warming. There's the famous example of a senator throwing a snowball to disprove 'global warming' on the floor of the senate. And you have to think, he sort of has a point.

For example, the Antarctic sea ice extent is above average this year. I've been talking to a glaciologist who says that the ocean ice has actually built up over the last year as a result of increased precipitation in the region.

This increased precipitation is an interesting effect of climate change because it means our atmosphere is changing it's normal behavior. This can be devastating as we've seen in the floods in Louisiana, for example, which were made more extreme as a result of climate change. 

However, if you look to the north to the Arctic sea ice extent, you'll notice that it is 23.1% below the 1981-2010 average. So the northern ice is melting while the Antarctic sea ice is increasing. Slightly. The net effect is a decrease in ice and thus an increase in global sea levels. 

There is a lesson to be learned here. If we're talking about global climate change, we have to think both long-term and globally. Although there are often surprising local effects such as extreme weather and colder temperatures that occur due to previously unseen interactions between the ocean currents, atmosphere, and changing weather patterns, the August 2016 report and other studies show that the earth is warming. Globally. 

As we're learning, this global change drives smaller, sometimes devastating effects as well as the long term concern of higher sea levels (which have equally, if not more devastating effects on global economies, coastal cities and habitats, international displacement, etc, etc). 

So as our home planet changes, let's keep our eyes and ears open to the new (sometimes scary, sometimes fascinating, sometimes both) ways that our climate changes and evolves. Because now, more than ever, it's increasingly important to understand the interconnected climate web of our home planet.

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A big week for the moon

It's easy to go about your days and nights here on Earth and ignore that giant companion that orbits us. However, this week a lot is going on for the moon, so let's give it some attention.

The moon during a lunar eclipse often appears red due to refraction from light bending through Earth's atmosphere. Blue light is higher energy, so it tends to be scattered away by particles in our atmosphere. Hence, only the red light survives to reflect off the lunar surface.  (Image Credit: Alfredo Garcia, Jr., Flickr)

The moon during a lunar eclipse often appears red due to refraction from light bending through Earth's atmosphere. Blue light is higher energy, so it tends to be scattered away by particles in our atmosphere. Hence, only the red light survives to reflect off the lunar surface. 

(Image Credit: Alfredo Garcia, Jr., Flickr)

First off, it's a full moon tonight! Specifically, a Harvest moon. In some parts of the world it's also a lunar eclipse tonight, although not for North and South America. Bummer for us.

Second, this week there was a cool bit of news concerning a new theory on the formation of the Earth's moon.

Let's tackle the Harvest moon/ lunar eclipse tidbit first. A Harvest moon is the name of the full moon that occurs closest to the autumnal equinox, which is September 22 this year. The equinox is an important date because it marks the day of the year when the northern hemisphere transitions from summer to fall.

Equinox actually means "equal night" in Latin which implies that day and night should be 12 hours each. This doesn't actually end up happening due to the fact that latitude also determines the length of one's day/night. However, this is mostly true in general due to the fact that the Earth's polar axis has a tilt that is pointing neither at the sun nor away from it during the equinoxes.

As you can probably guess, the full moon nearest the fall equinox would be named after the harvest due to the fact that farmers in the northern-hemisphere-centric world are generally harvesting their crops during this time of year.

Okay, moving on to lunar eclipses. A lunar eclipse happens during a full moon because the moon is on the opposite side of Earth from the sun (so we can see it fully illuminated at night). However, recall that the Earth is rotating over the course of the night AND that the moon is orbiting Earth about every month. Let's do some quick math. Over the course of one 24 hour period, or ~1/30th of a month, the moon will orbit through ~1/30th of its full orbit or 1/30th of 360 degrees, which is 12 degrees. So the lunar eclipse is not visible for everyone, because the moon will eventually leave the shadow of the Earth. Additionally, the orbit of the moon is on a slight tilt relative to the plane of the Earth and the sun, meaning that the moon is rarely perfect aligned with the shadow of the Earth. So while most of the Earth can see the eclipse today/tonight, the moon has rotated out of the shadow of the Earth by the time night rolls around for the North and South America.

The moons of the solar system. (Image Credit: NASA)

The moons of the solar system. (Image Credit: NASA)

Let's talk about the big moon news from this week. Astronomers have known that the moon is weird for quite some time. It's highly unusual for a planet as puny as the Earth to have such a large companion. It's hard for Earth to gravitationally capture an object this large. Just look at the other planets and moons in our solar system. Saturn and Jupiter have a plethora of large moons that compare in size to the moon, but planets similar to the Earth in size have tiny moons (such as Mars' Phobos and Deimos).

So what gives?

The most widely accepted scientific theory for the formation of moon is the giant impact hypothesis. It is exactly what it sounds like. A giant impactor, named Theia, smashed into the Earth in a relatively low energy collision. The debris from this collision coalesced into the moon. However, computer simulations of this low energy giant impact predicted that most of the moon should consist of material from Theia. 

The problem is that the composition of the Earth and moon match almost exactly. This seems unlikely if the moon were built mostly from another unknown composition. Statistically, Theia's composition should not exactly match that of Earth. Scientists thought more precise measurements of composition might resolve this problem but a study in 2016 only confirmed the existing problem.

So what are the new theories? How can the moon's composition so closely match that of Earth? The leading theory so far is a higher energy collision that vaporized Theia and the early Earth down to the entire mantle! This would explain how the surface compositions of the moon is slightly richer in potassium-41, which a heavier isotope of potassium. This heavier isotope would have a chance to condense in a high pressure cloud that the moon formed from in the higher energy impact event. 

So as you take the time tonight to gaze up at the Harvest moon, spend a second to think about the fact that we're still in the process of learning about our closest companion.

 

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