Posts Tagged ‘sun’

Last Shuttle Launch and A Comet Across the Sun’s Bow

July 8, 2011 Leave a comment

Some cool stuff happening in and around space these last couple days.

This video from the Solar Dynamics Observatory shows a comet streaking across the face of the Sun!!

And of course, the final shuttle launch EVER happened earlier today.

Screen grab of video from NASA website.

Big-Ass Explosion on the Sun

June 8, 2011 Leave a comment

A magnificent solar flare erupted from the Sun yesterday.

Here’s a really cool video put together at in the UV range. (Watch it in HD for the full ‘KABOOM!’ effect)


February 17, 2011 1 comment

Photo Courtesy of NASA

Happy Valentine’s Day, indeed.

The largest solar flare in 4 years erupted on Monday night. It is what as known as an X-class flare. As the name implies, it is a big-time event.

Solar flares are classified based upon the intensity of x-rays emitted between the wavelengths of 1 and 8 Angstroms. (An angstrom is 1 x 10-10 meters).

In order to be an X-class flare, the intensity of the flare must be greater than 10-4 Watts/m2. This flare is an X2 flare, meaning it has an intensity of about 2 x 10-4 Watts/m2.

The flare is sending waves of energetic particles at the Earth, which have already caused radio disruptions in China.

The main event will be coming Today, however. The bulk of the particles will be hitting the Earth’s magnetic field sometime today, possibly causing some intense Aurora’s.

So if you are outside at all this evening, take a quick look up and see if anything is happening. Regions closer to the equator which don’t normally see Aurora’s may just get lucky tonight.

(Bonus points to those who got the ‘Airplane!’ reference in the title of this post)

Update: Phil Plait uploaded a cool video of the flare. Check it out:

Awesome Video of the Moon Crossing the Sun

October 20, 2010 Leave a comment

The Solar Dynamics Observatory (SDO)

is designed to help us understand the Sun’s influence on Earth and Near-Earth space by studying the solar atmosphere on small scales of space and time and in many wavelengths simultaneously.

 But also (and perhaps more importantly), it takes some pretty sweet pictures and videos.

 Take this one which I saw posted on Bad Astronomy. It shows the moon moving between the SDO and the Sun, making the moon clearly visible as it crosses the disc of the Sun.


Sorry Creationists, Radiometric Dating Still Works

September 21, 2010 2 comments

About a month ago, there was a story about scientists from Purdue University claiming that they have measured changes in decay rates of certain isotopes. The changes, they claimed, corresponded to the orbit of the Earth around the sun, and the rotation of the core of the sun.

They hypothesized that it could be neutrinos emitted from the sun’s core interacting with the radioactive substances, causing a change in their decay rate.

I’ve written a post previously on radiometric dating. The technique is used to estimate the age of archaeological samples and rocks. It is used to determine the age of skeletons, fossils, and rocks. The geologic history of the Earth is based on these techniques, and it is how we know how old the Earth is.

So any inconsistency with the decay rate of an isotope we use for these dating techniques would be interesting indeed. But, perhaps not surprisingly, I am skeptical.

One of the scientists was quoted as saying,

What we’re suggesting is that something that can’t interact with anything is changing something that can’t be changed.

Very aptly put. Neutrinos are particles emitted by the sun and very nearly massless. Billions of them pass through you every second and do not interact with the atoms and molecules in your body.

So the idea that they may, somehow, be able to change the decay rates of radioactive isotopes is quite an extraordinary claim, and it therefore requires extraordinary evidence.

This article states that

The Purdue team has ruled out the possibility of experimental error or an environmental influence on the detection systems.

That claim, any scientist will tell you, is at best bold, and at worst laughable. Being able to conclusively eliminate all environmental factors is very difficult indeed. Particularly in the work of these scientists, who used data and labs in several different locations.

That the orbit of the Earth could have any measurable effect on these isotopes is very unlikely. Consider this. Some have claimed that because the Earth’s orbit is elliptical,  the Earth is sometimes closer to the sun than at another part of the year. This could increase the flux of neutrinos and possibly account for changing decay rates of isotopes.

The Difference in Earth-Sun distance between aphelion and perihelion is about 4 million km (diagram is not to scale). Picture Credit: NASA

This seems unlikely, since the flux of neutrinos changes by only about 5% though the course of the year (I did that math myself, feel free to check it if you wish).

In addition, their study looked at decay rates of several different isotopes, and used data from a variety of labs. This is not a controlled experiment, but we can’t discount the findings simply because of that. However, they also found that the change of decay rate they measured was not the same for all of the isotopes they studied. So this could mean that the neutrinos are interacting differently with each isotope, or it could mean they are simply getting anomalous readings.

Other scientists are starting to respond as well. A study was recently published which measured the decay rate of Gold-198 over several weeks. The researchers set up the experiment so that one sample got many times more neutrinos bombarding it than the control sample. No detectable change in radioactive decay was measured.

So the question is still largely unsettled. Oh but wait. Even though Creationists and Young Earth Theorists love to take studies like this and spin them to say that the Earth may not be as old as we thought, consider this…

The changes the Purdue researchers measured were fractions of a percent. They would not have any significant effect on the dating of any geological or archaeological sample. So even if their numbers are right (which I don’t think they are) they wouldn’t affect our measurement of the age of the Earth.

But this is what science is all about. Making a discovery and then trying to prove it to the rest of the world. Whether the neutrino theory turns out to be true or not, it is a classic example of why science works.

‘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.

Easter Island Solar Eclipse

July 16, 2010 Leave a comment

Easter Island is famous for its giant moai statues.

Moai Statue on Easter Island

But on July 11th 2010, the island was in a small corridor on the Earth from which a total solar eclipse was visible. This absolutely fantastic picture was captured by Stephane Guisard

Click the photo for high-res version

With the moai statues in the foreground, this is one the coolest photos I’ve seen in a long, long time.

This photo was truly a once in a lifetime opportunity. As can be seen in the diagram below, the total eclipse is always only visible from a very small region.

Totality is visible in the dark blue region. From: NASA

I love solar eclipses. Too bad the next one where I live won’t be coming around for another 30 years or so.

The Physics of Solar Power

July 6, 2010 2 comments

In my previous post, I discussed how President Obama is helping to fund the development of Solar Energy. I thought I would then take the opportunity to explain a bit of the physics behind solar power.

Don’t worry, you won’t find any equations here :)

First, lets start with the sun. That big bright thing up in the sky.

The sun generates light, and light can be thought of as a bunch of tiny packets of energy. These packets are called “photons”. The different amounts of energy in a photon will correspond to the colour of the light that is emitted. For example, photons of the colour blue have more energy than photons of the colour red.

Energy increases from left to right (Source: Opensource Handbook of Nanoscience and Nanotechnology)


So how do we harness the energy in these photons? We can use Photovoltaic cells. Put simply, they convert solar energy into electricity. Let’s see how…

A photovoltaic cell is made of special materials called semiconductors, which are made of things like silicon (Yes, that stuff used to make fake boobs. Isn’t science awesome?).

Now, all atoms are made up of a nucleus (which is made of protons and neutrons) and electrons which circle around the nucleus.

Electrons can actually absorb the energy from a photon, but this happens only if the photon has a very specific amount of energy (a specific colour). When an electron does absorb a photon, it causes the electron to “jump”, and sometimes even break free of the entire atom! Electricity is a constant flow of electrons, which we refer to as an electric current.

Silicon structures like to hold onto their electrons. They don’t normally let them move around which makes silicon what we call an insulator. But in a Photovoltaic cell we add impurities, little bits of stuff that doesn’t belong there. The impurities will actually encourage the silicon to release its electrons and let them move around.

Now the magic happens. So a photon (those little packets of energy from the sun) hits the Photovoltaic cell. If the photon has just the right energy, it will knock loose one of the electrons in the silicon atoms. And, because of the impurities, that electron will move around.

If you get enough electrons moving around, you get an electric current which we can then use to power all of our awesome toys!

Thats it in a nutshell. If you want to read about this stuff in a bit more detail, check out the links spread all through this post, or some of the cool sites below.

Hooray for Physics!

Further Reading:

Deep Space Probe IKAROS: Update

June 17, 2010 Leave a comment

I recently wrote about the new Japanese space probe IKAROS. It is the first probe designed to test the idea of using solar sails to travel the universe.

A couple new photos were just released showing IKAROS with its sail unfurling, confirming the first stage of its mission.

IKAROS with sails in the process of unfolding. Photo: JAXA

IKAROS with solar sail completely unfurled. Photo: JAXA

Now its just a matter of getting it up to speed. I’m really interested in this one folks, and I’ll keep you up to date.