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Posts Tagged ‘earth’

What Does a Black Hole Look Like?

December 9, 2010 Leave a comment

Credit & Copyright: Alain Riazuelo - Click Image for Large Version

Not to sound like a smart ass…but it would look like a big black hole.

This is a computer generated image by Alain Riazuelo and I saw it the other day as the Astronomy Picture of the Day.

Aside from eating all the light hitting the black hole straight on, notice the “rings” around it as well. This is called gravitational lensing, and is something astronomers look for in order to identify a black hole, since the lensing is easily visible at a larger distance.

We Got Asteroid Dust!

November 16, 2010 Leave a comment

Phew. Gotta clean the dust off my computer. Why does moving have to take up so much time?

Well while I was lugging heavy boxes, there was stuff still going on in the world of science.

Perhaps the thing that got me most excited was that the spacecraft Hayabusa, which I have written about before, has succeeded in its mission!

Hayabusa Spacecraft. Image Credit: JAXA

Japanese researchers announced that the craft has acquired fragments of asteroid dust and returned them safely to Earth.

The craft was launched seven years ago, and in 2005 it landed on asteroid Itokawa. Despite some engine trouble, and the fact that the ball bearing it was supposed to shoot into the asteroid’s surface failed to fire, the craft still managed to collect some fragments of space dust.

Asteroid Itokawa. Courtesy of JAXA

Hayabusa returned to Earth in June of 2010, and we have been waiting anxiously for months to find out if the craft had actually gotten some asteroid bits back for us to study.

How do we know these particles are definitely from the asteroid? The official announcement states:

The mineral phases among the collected 1500 particles, their relative abundance ratios and their elemental compositions agree with a class of primitive meteorite, and they do NOT correspond to any rock type on the surface of the Earth.

This absolutely blows my mind! These guys were able to launch a spacecraft, land it on an asteroid, take off from the asteroid and return to Earth with pieces of it!

I think we all need to take a moment and think what it would be like to be working on this project from the start. Seven long years it took, with obstacles almost every step of the way, and now they find out that it was totally worth it. Kudos these researchers, who are no doubt still out partying in celebration.

A Young Earth Creationist Called Me a “Dim Wheel”…

October 1, 2010 Leave a comment

I’m not even sure what that means, but I don’t imagine it is complimentary. It’s also the first openly hostile comment I’ve gotten on my blog, so I figured I’d share my thoughts on it.

The comment appeared on my post called: “Sorry Creationists, Radiometric Dating Still Works”. The post had to do with the recent stories in the news about neutrinos possibly affecting the decay rates of isotopes used in radiometric dating. The results are in still question, and even if true, would not drastically affect the dating of geological samples which have already been performed.

One person, who chose to remain anonymous, commented on the post. They said (all grammatical errors reproduced exactly): 

Guess what Dim Wheel, diamonds have measurable amounts of C-14. You Kind of sound like a scientist, but lets face it, your not.

Now, I don’t have a problem with comments that disagree with me, but name-calling is just childish. Am I a scientist? Well I have an M.Sc. in Physics, and I work in the technology sector analyzing data, writing code and working my way into the R&D department. But I think the commenter is saying that I don’t wear a lab coat or work at a University, so I suppose I am not a “scientist” by that definition. But ad hominem fallacies aside, lets deal with the diamond argument.

I had actually never heard this argument before, so I looked it up. Diamonds are old. Very, very old. So old in fact, that Carbon-14 should not be present at all in diamonds, it should have all decayed away millions of years ago. So Young Earthers use this argument as evidence that the earth is younger than scientists thought.

Here was my response to the comment:

Diamonds do actually contain Carbon-14. This has been in known for about 30 years now, and is easily explained.

Uranium decay in geological samples can actually trigger the generation of a Carbon-14 isotope in a sample of diamond. This phenomenon has been thoroughly studied and confirmed. Here are a couple references:

Excess carbon-14 abundances in uranium ores: Possible evidence for emission from uranium-series isotopes.
D. Barker, A. J. T. Jull, and D. J. Donahue. Geophysical Research Letters, Volume 12, Issue 10, p. 737-740 (1985)

14C in uranium and thorium minerals: a signature of cluster radioactivity? R. Bonetti et. al.
European Physical Journal A, Vol. 5, No. 2, 235-238 (1999)

If you have any other questions regarding this matter please don’t hesitate to ask. I’d be happy to answer them for you.

So the argument doesn’t hold water, but what gets me more is the hostility. I know I shouldn’t be surprised, and we skeptics have a reputation of being “dicks” sometimes as well. But it is totally counter-productive from either side of the argument to act like a jerk or commit the ad hominem fallacy.

So you can read the comment yourself, and let me know if you think my response was well-handled. I love scientific discussion, but I don’t like confrontation. Discussion makes you learn and question your own beliefs, whereas confrontation just causes you to dig in your heels and become more close-minded.

Can’t we all just get along?

‘Tis the Season…for Ozone Depletion

September 11, 2010 Leave a comment

Around this time each year in the Southern Hemisphere, the winter turns to spring. This brings with it warmer temperatures, but also the infamous ozone hole.

The direct sunlight which bombards the Antarctica region during the summer months causes chemical reactions to occur which destroy ozone molecules. Ozone, of course, is our natural protector against ultraviolet rays from the sun.

So the ozone “hole” isn’t really a hole, but more of an area of marked depletion of ozone.

NASA has been studying and quantifying the extent of ozone depletion in the area since 1979. The hole reached a maximum on 24 September 2006.

Ozone hole on 24 September 2006. Blue areas indicate areas of depleted ozone.

There is much more information on NASA’s Ozone Hole Watch website, so be sure to check it out. And always remember to reapply suncreen every 2 hours.

Our Glorious Planet: As Seen From Mercury

August 20, 2010 3 comments

I never ceases to amaze me just how massive the universe is.

Take for example, this photo of the Earth and our moon, taken from roughly 114 million miles away.

Image Courtesy of NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Click on the image to wonderfully aggrandize (thank you Thesaurus.com).

The image was taken from a NASA mission called MESSENGER (MErcury Surface, Space ENvironment, GEochemistry and Ranging). MESSENGER was launched in 2004 and has done 3 flybys of Mercury, on its way to be in a permanent orbit to study the planet in 2011.

It is truly humbling to see our planet as a tiny speck in the vastness of space.

As Carl Sagan would say: “One voice in the cosmic fugue.”

The Physics of Carbon Dating

August 13, 2010 Leave a comment

When I was a kid, I wanted to be a hockey player. Then a doctor. Then a paleontologist. Then I saw Raiders of the Lost Ark and I wanted to be an archeaologist.

Well one thing led to another, and I ended up getting a Physics degree instead. Luckily for me though, studying physics gave me the tools and experience to understand all kinds of stuff from other scientific fields.

Take archeology and geology for example. One of the primary tools in this field for determining the age of a specimen is radio-carbon dating. But how does it work, and why do we place so much stock in its results?

Lets start at the beginning. Carbon is atomic element #6. The most abundant form of Carbon is Carbon-12, which has 6 protons and 6 neutrons in its nucleus (6 + 6 = Carbon-12).

We are Carbon-based life forms. Carbon has the ability to form huge molecules making our existence possible. (Silicon also has the ability to form big molecules, which Star Trek has taken advantage of to create some crazy looking Silicon-based aliens).

But there is another form of Carbon out there: Carbon-14 (C14 for short), which has 6 protons and 8 neutrons.

C14 is unstable. That extra neutrons cause problems in the nucleus so eventually Carbon-14 will decay into the happy and stable Nitrogen-14 (which actually makes up 78% of the air we breathe).

So how does this help us with dating stuff? Well C14 is naturally created in the atmosphere. So at any given time, there is a certain amount of C14 in the atmosphere. So when plants undergo photosynthesis, which is when plants take in Carbon dioxide and sunlight to make energy, they absorb some C14 at the same time. After this happens, animals will eat these plants and absorb some C14  themselves.

From: HowStuffWorks.com

Long story short, all living things will have a certain amount of C14 in their systems while they are alive.

But when plants or animals die, they stop taking in C14 from the environment. And since C14 is unstable, it will start to decay.

C14 has a half-life of 5730 years. This means that one half of C14 in a sample will decay after one half-life. For example, if you had 10 grams C14 atoms and waited 5730 years, 5 grams will have decayed, and you would have 5 grams of C14 left. If you waited another 5730 years, 2.5 grams will have decayed and you would have 2.5 grams left, and so on.

So scientists can take a fossilized sample of bone or plant, compare the amount of C14 in the sample to what should be in living tissue, and they can calculate how old the sample must be.

Granted, this is a simplified explanation I have given here, and there are other factors to consider. But calibration of the technique is very good, and we can get an accuracy of the age of a sample to with +/-16 years for a sample younger than 6000 years, and within 160 years for samples less than 50,000 years old.

After 50,000 years, C14 dating doesn’t work so well, because there just isn’t enough C14 to make an accurate measurement. But there are other elements with long half-lives that we can use to date much older stuff, and they all work on the same general principle as what I’ve explained here.

Many Intelligent Design proponents and Young Earth theorists will try and disprove these techniques. They may give arguments about how concentration of C14 has not been constant over the past 50,000 years. This is actually true, but we can account for it in our measurement.

So sorry IDers, the Earth was not created 6000 years ago. It was created roughly 4.5 billion years ago which, I think, is much more awesome.