Archive for the ‘You Need To Know – but Everyone Else’s Already Posted It’ Category

Quick Summary

Dr. Felisa © 2010 Henry Bortman

NASA Astrobiology Scientist Dr. Felisa Wolfe-Simon (herein referred to as Felisa, per my attempt to make scientists sound like the real people they are) has bred a bacteria that uses arsenic in its molecules instead of phosphorus. So, if people are asking you about NASA’s Big Alien Life Announcement™, that’s it. It’s Earth-life though, not alien life.

Why Is This Cool?

In short, this opens the door for life being “not as we know it” – or at least based on other atoms than all life we have thus far found.

A Short Lesson in Biochemistry

“Carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur are the six basic building blocks of all known forms of life on Earth.” So – if you’re studying biochemistry you get to play with C, H, N, O, P, and S in as many combinations as you can think of. Sometimes you get to play with others too, but not a lot. This is also most of what makes up your body, though you’ll be able to name a few notable others we have an need (like Iron – Fe), but they’re minor on the scale of how much there is in a lifeform.

Phosphorus is key. So are the others, of course, but for this article we’re discussing P today. Phosphorus is essential in DNA and RNA, and most interesting to me, essential in ATP (bear with me for a second). I personally have no problem with the idea of replacing phosporus in a molecule (like DNA) with some other atom that makes the same number of bonds – like arsenic. Yes it will change the shape, but you can actually do it. Experts in the area DO have a problem.

Here’s what I think is cool: ATP is how a cell stores energy. When you break an ATP molecule (tri-phosphate) into an ADP (di-phosphate) molecule and associate components, you get energy out of that reaction. That’s how chemistry works – some reactions take energy, some give energy. So, it surprises me that when you make AT-Arsenic you’d get a reasonably correct amount of energy to power a cell.

How GFAJ-1 Came To Be

GFAJ-1 courtesy NASA

Felisa was studying bacteria at Mono Lake – a lake in Eastern California with fascinating chemistry, including high levels of arsenic. Taking some of these bacteria, already accustomed to living with levels of arsenic (toxic to most life), she exposed successive generations to higher and higher levels of arsenic, replacing the phosphorus in their environment, until eventually the creatively-named GFAJ-1 was living and reproducing without taking in ANY new phosphorus.

This is where other scientists become skeptical, but not so skeptical as to say “no way!”. Just because the bacteria aren’t taking in phosphorus, doesn’t mean they have incorporated the arsenic into their molecules in place of the phosphorus. Felisa says, among many reasoned arguments: wait for the next paper, which she’s already written but hasn’t been published, and you’ll see some stronger evidence supporting that arsenic is being incorporated in place of the phosphorus.

Skeptical?

In true scientific fashion NASA introduced an expert chemist Dr. Steven Benner to, in his own words, “throw a wet blanket on things” and explain why this discovery/claim/finding is so extraordinary – so extraordinary as to need extraordinary proof (as Carl Sagan so famously said). In short, his difficulty is that arsenic formed into arsenate is much much weaker than phosphate, and therefore the DNA chains and other molecules are much more likely to fall apart. This would mean that life would choose phosphate over arsenate, or it would have to adapt significantly to support this weaker molecule.

A Couple Quick Random Interesting Thoughts

• This press conference was dominated by women scientists! Yay! 
• I am not a biochemist, and I don’t completely understand what’s at play here, but I have long argued with one of my astronomy professors that Silicon-based life is entirely possible, we don’t have a way to disprove it yet. (Silicon making the same bonds as Carbon). Well, he staunchly and legitimately argues against me, but I think this finding gives my side a LITTLE bit more weight.
• I am struck by the similarity, and yet complete difference, between this and the discovery of life at hydrothermal vents. They too have distinct biochemistry, though their molecules are all normal. They don’t conduct photosynthesis (with a biproduct of oxygen), they conduct chemosynthesis (with a biproduct of sulfur). Noteably they still have a good amount of oxygen in their chemical makeup, it’s their source of energy which is different.

Want More?

NASA’s Press Release

My Two Favorite Bits of the NASA Press Conference: Felisa speaking (about 2 minutes in), and Steven explaining what needs to be thought about.

A Chemist’s View

~ A l i c e !

I just got this in my e-mail. I can’t tell if this is a new “Comet McNaught” or a new approach by the same one we saw a couple years ago. This is a different comet than the “Comet McNaught” discovered a few years ago, but it was discovered by the same person! In any case – enjoy!

Space Weather News for June 8, 2010
http://spaceweather.com

NEW COMET McNAUGHT: A fresh comet is swinging through the inner solar system, and it is brightening rapidly as it approaches Earth for a 100 million mile close encounter in mid-June. Comet McNaught (C/2009 R1) has a vivid green head and a long wispy tail that look great through small telescopes. By the end of the month it could be visible to the naked eye perhaps as bright as the stars of the Big Dipper. Because this is the comet’s first visit to the inner solar system, predictions of future brightness are necessarily uncertain; amateur astronomers should be alert for the unexpected. Visit http://spaceweather.com for sky maps, photos and more information.

You are subscribed to the Space Weather mailing list, a free service of Spaceweather.com.

New subscribers may sign up for free space weather alerts at http://spaceweather.com/services/ .

~ A l i c e !

Eyjafjallajökull's ash plume in April 2010 from NASA's Earth Observatory

The Eruptions

Eyjafjallajökull has been active in the last few days. Dr. Erik Klemetti of Eruptions blog has a great write up. Go listen to him. Also, Jorge Santos has the best picture of the ash.

Most recently, on 4/14/2010 (or 14-4-2010 if you’re not in the US):

After a few days of quiet in Eyjafjallajökull volcano, a new and much more forceful eruption has begun west of Fimmvörðuháls, under the ice-cap.

The eruption is below the highest peak of Eyjafjallajökull, at the southern rim of the caldera.

A plume rises at least 8 km into the air. No lava is seen yet but melt-water flows both north and south of the mountain.

-Iceland Meteorologic Office

At 2300 on 13 April, a seismic swarm was detected below the central part of Eyjafjöll, W of the previous eruption fissures. About an hour later, the onset of seismic tremor heralded an eruption from a new vent on the S rim of the central caldera, capped by Eyjafjallajökull glacier. The eruption was visually confirmed early in the morning on 14 April; an eruption plume rose at least 8 km above the glacier. Meltwater flowed to the N and S. News outlets reported that a circular ice-free area about 200 m in diameter was seen near the summit. Scientists conducting an overflight saw a new 2-km-long, N-S-trending fissure, and ashfall to the E. About 700 people were ordered to evacuate the area, and certain flights were banned from flying N and E of the eruption area. Flooding increased throughout the day, causing road closures and some structural damage.

-Institute of Earth Sciences

The Volcano

Eyjafjöll is also known as Eyjafjallajökull. It’s a strato volcano – so more of a pointy volcano (like Mount Vesuvius), less of a flat volcano (like Hawai’i). Eruptions from strato volcanoes are often more powerful and spread more ash and less lava. Near Seattle the Cascades have many strato volcanoes: Mount Rainier, Mount Saint Helens, Crater Lake, Shasta, etc.

Good places for more information?

The volcano itself (from the Global Volcanism Program).

The eruption on 4/14/2010 (from the Iceland Meteorological Service)

News from the Iceland Meteorological Service

USGS Worldwide Volcanic Activity Report

NASA’s Earth Observatory Photographs from Space

~ A l i c e !

The fabulous and illustrious duo Beth and James requested that I educate you all further on the relationship between the Chilean Quake and the rotation of the Earth. A worthy topic.

In Short

The big earthquake in Chile shifted enough of the mass of the Earth far enough that (like a figure skater bringing her arms in toward his body) the Earth actually sped up slightly – shortening our day by 1.26 microseconds. Maybe – the number will be refined further.

Quote

JPL research scientist Richard Gross computed how Earth’s rotation should have changed as a result of the Feb. 27 quake. Using a complex model, he and fellow scientists came up with a preliminary calculation that the quake should have shortened the length of an Earth day by about 1.26 microseconds (a microsecond is one millionth of a second).

Perhaps more impressive is how much the quake shifted Earth’s axis. Gross calculates the quake should have moved Earth’s figure axis (the axis about which Earth’s mass is balanced) by 2.7 milliarcseconds (about 8 centimeters, or 3 inches). Earth’s figure axis is not the same as its north-south axis; they are offset by about 10 meters (about 33 feet).

-JPL Media

In Detail

Overwhelmed? I’ve highlighted the pieces you should pull out of that.

Conservation of Angular Momentum

You cannot create energy or matter out of nothing. These laws are called “conservation of matter” and “conservation of energy.” We’ve got one for spin (angular momentum) too. If you’re spinning you either keep spinning (at the same speed) or you pass off some of that momentum to another object. This causes the oft-referenced effect of the figure skater’s pirouette. She begins to spin with her arms out, gets up some speed, and then pulls her arms and legs in tight. She spins significantly faster in this configuration. Later she puts her arms out again and slows down.

You can do this at home. Grab two cans of food and a spinning office chair. If you do not also find yourself at least fifteen by fifteen feet square of clear space, I take not responsibility for your bruised knuckles (you WILL knock into something if you don’t have plenty of room around, so don’t hurt yourself). Get a friend to start you spinning, with the cans held at arms length in your hands. As soon as you’re going, pull the cans in to your body. Try it the other way – starting with your arms in too.

This is conservation of angular momentum.

Figure Axis

Why were we talking about that? Because of the figure axis. You know the Earth is round, and you also know the Earth is not a perfect sphere because of that hill you had to bike up to get to work today. The Earth rotates on its axis, once a day, and that axis is pointed at the North star.

Now, imagine your washing machine – it spins too. Where is that axis? Yup, right down the middle. The figure axis is different though – it’s the axis around which the mass is all balanced. In a normal situation for your washing machine, these two axes are about the same. Now imagine it gets off balance – all your clothes end up on one side of the drum.

First, where is the spin axis? Yes! Same exact place – right down the middle (sorta, you hope). The mass (your soggy clothes) have changed places though, and they’re all on one side. Imagine a line that intersects the middle of the clothes pile. It’s off to one side, and in fact, as the washing machine spins, the figure axis is rotating around the spin axis with the clothes.

Re-balance your load of laundry so it doesn’t make your washing machine walk and let’s talk about the Earth.

The Earth’s figure axis (balance of mass) is very close to its spin axis, but they aren’t the same. If you move one of the Earth’s plates a lot – it’s like moving the towel in the laundry around, you’re messing with the balance of the mass. In the case of the Chilean earthquake we have one plate subducting under another, which means some mass moving closer to the center of the Earth. It’s not moving far, it’s not getting that much closer to the Earth, but if you’re doing minute calculations it is definitely enough to have that conservation of angular momentum effect (spin a little faster as mass moves in) due to the shifting of the mass of the Earth.

Calendar Change

A student came up and asked today if that meant the atomic clocks needed to change. Well, no, but the atomic clocks are pretty much just counting time passing anyway, in oscillations specific atoms. The question you want to ask is, are the “atomic calendars” going to change?

First off, I must point out I don’t know if there are calendars kept to the level of accuracy that is implied in the term “atomic calendar.” Perhaps these folks?

Second, no, not yet. Richard Gross’s calculations are preliminary. Once they are solidified, the next leap second will take care of it. Does that mean a leap second isn’t actually exactly a second?

Want More?

The JPL Release

Microseconds – a measure of time

Milliarcseconds – a measure of angle (like a degree is a measure of angle)

International Earth Rotation and Reference Systems Service

I’m embarrassed to say, but I got the idea for the  washing machine analogy off Yahoo Answers. I was just going to use the figure skater till I read the concept there. I’m also going to have to talk about the ways the Earth moves sometime.

~ A l i c e !

Check out Carnival of Space #147 hosted by Weird Sciences. Phil’s got a great post linked.

~ A l i c e !

If you’re not currently subscribed to my new feed through feedburner you should be. It’s easy just click here, or click the orange box at the top of the page near the search bar, or input http://feeds.feedburner.com/AlicesAstroInfo into your favorite RSS feed reader.

Onward:

Carnival of Space #146 is live at Simioastronomy – check it out, lots of Hubble goodness.

Also, Seattle Astronomy Examiner Greg Schneiderer reports on my Equinox Sunset party from Saturday evening. He’s got photos in case you missed it.

~ A l i c e !

One of the most basic questions when it comes to Martian expeditions is communication, namely “how long does it take to communicate with Mars?” The simple short answer is 4-20 minutes, depending on where the Earth and Mars are in their orbits. It also gets more difficult when Mars is near or behind the Sun from our point of view.

Interplanetary Internet

You’re probably quite used to looking up the answers to your questions on the internet anytime you want, but with the delay in communication in space, the internet can’t work quite the same way – besides the fact that you’ll be using a connection that feels like a very, very slow modem. The way webpages are designed now that would take forever.

Data Rates

Of the missions currently at the red planet, the Mars Reconnaissance Orbiter (MRO) has the ability to transmit the most data. Its data speed to and from Mars is about 6 megabits per second (about twice as fast as the connection I’m currently on), but that’s not continuous – it is only when MRO can “see” Earth. Since Mars is rotating, the rovers are periodically out of contact, and the satellites lose their connection when they orbit to the far side of the planet.

Eeep! We’re using speed in two different ways. Don’t confuse the speed at which the data is transmitted (the amount of data per second) with how long it takes the data to get to Earth. MRO may transmit at 6 megabits per second, whereas Spirit can only transmit directly to Earth at a maximum of 12,000 bits per second (that’s 0.01 megabits per second – like using a very old dial-up modem!), but still both messages will take the exact same amount of time to get to Earth: between 4 and 20 minutes, depending on the time of year.

Relays

Most messages from space missions go through relay satellites, for example the Mars Rovers often send data through MRO. This in itself might make interplanetary internet a reality, if we can overcome some of the blocks – like the delay causing excessive timeouts among many others. There are some folks studying this problem, and there are even proposed solutions.

Incidentally, the International Space Station just got live internet for the first time – really it’s a connection to a computer in Mission Control – and that computer is connected to the internet. That limits the information that really needs to be transmitted to the Space Station.

Would You Like to Receive a Message from Mars?

Would you like to get some tourist snapshots of Mars? The surface of Mars? Well, your chance to point the HiRISE camera at your favorite part of Mars is here.

More Info:

http://deepspace.jpl.nasa.gov/dsn/

http://marsrovers.nasa.gov/mission/comm_data.html

~ A l i c e !