Solar Eclipse

Exciting event happening in Northern Australia!  =D  In the early morning of November 14 local time, (November 13 east of the International Date Line), there will be a total eclipse of the sun.  =)  So let's learn about it.  ;)

To understand eclipses, we need to keep the following in mind.  Simply put,

Image from: http://www.earthview.com/tutorial/patterns.htm

• The Earth follows a path around the Sun, while the Moon follows a path around the Earth.  
• Along its path as the Moon orbits, it moves between the Earth and the Sun.  Among the phases of the moon, this corresponds to the New Moon (or dark moon) wherein the Moon is not visible to us because it is the far side that is illuminated by sunlight.  During this time, it casts its shadow towards the Earth and a solar eclipse can occur.  
• Conversely, the Moon moves behind the Earth further along in its orbit.  This time, the Earth becomes positioned between the Sun and the Moon, and we see the moon as full.  During this time, the Moon may enter the Earth's shadow and a lunar eclipse can occur.  
• These phases of the moon cycle roughly every month, but solar and lunar eclipses do not happen that often because the plane of the Moon's orbit around the Earth is tilted about five degrees in relation to the plane of the Earth's orbit around the Sun.
• Most of the time, therefore, the Moon or its shadow passes above or below the Earth and its shadow, and an eclipse does not occur.  

• A solar eclipse may only occur when the Moon is near one of its nodes (i.e., the points along its orbit where it intersects the plane of Earth's orbit) during its New Moon phase.  
• One more interesting thing to note: during this New Moon phase, the Moon is actually in the sky during the daytime, moving along with the Sun.  We just don't see it because, as mentioned earlier, the illuminated side is the far side, plus it gets lost in the bright glare of sunlight.  The only time we notice it is during an eclipse when it obscures part of or the whole disk of the Sun.  
• Now, when the conditions are met and a solar eclipse occurs, it can be any one of the four types mentioned below.

Types of solar eclipses:

A. Total eclipse, B. Annular eclipse, C. Partial eclipse
Image from: http://en.wikipedia.org/wiki/Solar_eclipse 

1. Total solar eclipse 
• This occurs when the part of the Moon's shadow called the umbra reaches the surface of the Earth.  The umbra tracks a narrow path called the Path of Totality, which covers less than 1% of the Earth's surface.  This is the reason why total eclipses seem to be a rare event, even though it occurs rather frequently (about one total eclipse every one or two years).  You have to be at the right place at the right time to view it.  Also, the location where this shadow path hits the Earth will be different with every successive total eclipse.  The interval between two total eclipses occurring in one place can be very long.  
• It is very interesting to note that at present, the Sun's diameter is actually about 400 times that of the Moon's. But because the Sun is also about 400 times farther from the Earth than the Moon, their apparent sizes in the sky are about the same.  So when you are in the Path of Totality when the Moon moves directly in between the Earth and the Sun, the disk of the Moon will just about cover the disk of the Sun from your point of view.  (More on the phases and effects seen during a total eclipse below.)
2. Annular solar eclipse 
• A total eclipse does not always occur when the Moon moves directly in between the Earth and the Sun.  This is because the orbits are elliptical so that the distance between the Earth and the Moon (as well as between the Earth and the Sun) varies.  An eclipse will be total if it occurs when the Moon is nearer, and its apparent size is enough to cover the apparent size of the Sun. If the eclipse occurs when the Moon is farther, its apparent size will be smaller and may not be enough to cover the disk of the Sun.  If this is the case, the eclipse will be annular.  
• It is also noted that in this case, the tip of the umbra falls short and does not reach the surface of the Earth.  It is the antumbral shadow that reaches the surface that, similar to the above, tracks a narrow path on the surface, this time called the Path of Annularity.
• This type of solar eclipse is more a subset of partial eclipses, and you will not see the effects seen during a total eclipse.  The rim of the Sun is still seen around the dark disk of the moon, and this is known as the "Ring of Fire".  
3. Hybrid solar eclipse 
• This is a rare type also known as annular/total eclipse.  This occurs when, because of curvature of the Earth, the tip of the umbra reaches the surface at some points of the eclipse path, while at other points, it doesn't. The effect of this is that, at the points where the umbra reaches the surface, a total eclipse is observed, while at the other portions, an annular eclipse is observed.  
4. Partial solar eclipse 
• The part of the Moon's shadow called the penumbra covers a wider area.  So those that are outside the narrow paths of totality or annularity described in the above types of solar eclipses will be able to see a partial solar eclipse.  From their point of view, the Sun will only be partially obscured by the disk of the Moon, the degree of which will depend on how far they are from the direct path.  
• Purely partial eclipses can also occur. This happens when the umbra completely misses the Earth, passing either above the Northern pole or below the Southern pole, and only the penumbra touches the surface of the Earth.  

Phases and Effects of a Total Solar Eclipse:

Image from: http://en.wikipedia.org/wiki/Solar_eclipse

1. First contact  
• The edge of the Moon starts to overlap with the Sun's edge.
• The Moon progresses across the Sun covering more and more of it.  
• Daylight fades quickly a few minutes before totality.
• Shadow bands may be seen moving across the ground, caused by the distortion of sunlight refracting through the Earth's atmosphere. 
2. Second contact 
• Nearing the point where the Sun is completely obscured by the Moon, an effect called Baily's beads is seen where light from the Sun shines through along the edge owing to the irregular surface of the Moon.  When only one of these beads is left, it results in a diamond ring effect.  
3. Totality 
• The Sun is totally obscured by the Moon, and the sky gets very dark.   
• For a few seconds, the Sun's chromosphere is visible as a pinkish glow around the edge of the Moon.  
• The white solar corona, visible only during a total eclipse, is seen all around the Moon.
• Gigantic, red loops of gas called solar prominences are seen arching above the edges.  
• Brighter stars and planets become visible in the rest of the sky.
• Animals and plants behave as if it is nighttime.  
4. Third contact 
• The Sun reemerges from behind the Moon.  A diamond ring effect may be seen again.  The events before totality occurs in reverse order.  
• The Moon progresses from the Sun, uncovering more and more of it. Daylight returns. 
5. Fourth contact 
• The edge of the Moon ceases to overlap with the Sun and the eclipse ends.

Unfortunately for most of us, we won't be able to experience and see the total solar eclipse with our own eyes.  But fortunately, with today's technology, we may still be able share in the experience.  =)
http://www.space.com/18444-total-solar-eclipse-webcasts-2012.html
Enjoy!  =D

Eclipsed Earth.
Photo of the August 11, 1999 total solar eclipse taken from the Mir space station.
Image from: http://solarsystem.nasa.gov/planets/profile.cfm?Object=Sun
Credit: Centre National d'Etudes Spatiales

References and Suggested Readings:

• http://csep10.phys.utk.edu/astr161/lect/time/eclipses.html
• http://www.earthview.com/tutorial/tutorial.htm
• http://www.mreclipse.com/Special/SEprimer.html
• http://eclipse.gsfc.nasa.gov/solar.html
• http://www.exploratorium.edu/eclipse/
• http://en.wikipedia.org/wiki/Solar_eclipse
• http://www.space.com/15584-solar-eclipses.html

Scarlet Fever

This has been in the news recently so... what is it anyway?


Scarlet fever is an illness caused by a bacteria called Streptococcus pyogenes, or Group A beta-hemolytic Streptococci.  This is the same organism that causes 'strep throat', a bacterial type of pharyngitis (inflammation of the pharynx or throat).

In fact, the illness usually starts with similar symptoms including:
- fever of 38.3 Celsius (101 Fahrenheit) and above
- sore throat, with swollen tonsils covered by white or yellow spots of pus
- difficulty or pain on swallowing
- enlarged, tender lymph nodes in the neck
- chills, headache, nausea, vomiting, stomach pain

The difference is: scarlet fever is accompanied by a rash caused by a toxin the organism produces.  This characteristic rash is what gives scarlet fever its name.

The rash begins over the neck and upper body, and quickly spreads up to the arms and legs, usually within 24 hours.  It is made up of tiny bumps giving it the texture of gooseflesh or coarse sandpaper.  It is red, but blanches or turns pale on pressure.  The redness is more intense in the deep creases or folds of the skin in the neck, armpits, elbows, groin, and knees, forming red lines or streaks.  The face (forehead and cheeks) is also red and flushed, but the area around the mouth remains pale (circumoral pallor).

The tongue also has a characteristic appearance.  At first, it is covered with a white coat (and so is called white strawberry tongue), which is shed after several days leaving a red, bumpy-looking tongue (called red strawberry tongue or raspberry tongue).

Afterwards, the rash fades and the skin begins to peel, and this peeling may take from days to weeks.


Scarlet fever is most common in children of ages 5 to 15 years.  It is usually spread by droplets expelled from an infected person when he/she coughs or sneezes.  So it is good advice to cover the mouth and nose whenever coughing or sneezing, as well as avoiding sharing eating utensils, drinking glasses, and food.
From the time of exposure, it can take up to seven days to the appearance of symptoms.

To diagnose, the doctor will take a swab from the back of the throat and submit it to the laboratory for culture, to see if the bacteria will grow from it.  When this is confirmed, the doctor will prescribe a course of antibiotics.  Note that it is important to complete the course of antibiotics because if not, the bacteria may not be completely removed and develop into drug-resistant strains, and also increase the risk of complications.

Nine Planets?

My very eager mother just served us nine pizzas.

Or was it pies?  No matter.
This was the mnemonic taught to us so that we can remember the names of the nine planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto.

However, sometime in 2006, in light of new discoveries, the International Astronomical Union redefined the word 'planet' as: a celestial body that
a) is in orbit around the Sun,
b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and
c) has cleared the neighbourhood around its orbit. - This last bit means it has a clear path around the Sun.

With this definition, Pluto was reclassified as a dwarf planet because of its size and its location within the area called Kuiper Belt.

For comparison, the definition of a 'dwarf planet' is: a celestial body that
a) & b) - same as in the definition of planet above,
c) has not cleared the neighbourhood around its orbit, - meaning it orbits in a zone that has many other objects in it, and
d) is not a satellite.

Currently, there are five dwarf planets namely: Ceres - which is the largest body in the asteroid belt, in the area between Mars and Jupiter; Pluto, Haumea, Makemake, and Eris - which are all in the Kuiper Belt, in the area beyond Neptune.

And if anyone asks, there are eight planets, not nine.  And to remember them, think:

My very educated mother just served us nachos.

Hmm... I think I prefer nuggets, though...

Miranda Warning or Miranda Rights

You have the right to remain silent.  Anything you say can and will be used against you in a court of law.  You have the right to an attorney.  If you can not afford an attorney, one will be provided for you.

Anyone who has watched any cop/crime show has heard this.  This is what is referred to as the Miranda warning or Miranda rights.

It is a warning given to suspects in police custody before interrogation to inform them of their rights against self-incrimination.  If they have understood this right and choose to waive them, and speak to the police regarding the incident, any self-incriminating statements they make may be admissible as evidence in court.

The Miranda warning is required in the United States, but there are equivalent rights in other countries as well.


In the Philippines, the Miranda Doctrine is also followed as shown in Article III (Bill of Rights), section 12 of the 1987 Philippine Constitution (see excerpt below).  The Miranda warning is given to persons placed under arrest, whether with a warrant, or without (warantless arrest), in a language or dialect the person knows and understands.

If the person under arrest chooses to waive this right and give his statement, the arresting officer must ensure that the waiver is made in writing and signed by the arrested person in the presence of a counsel.

Growing Minds

"The purpose of learning is growth, and our minds, unlike our bodies, can continue growing as long as we live."

- Mortimer Adler

Learning is a lifelong process.  Everyday presents something for us to learn, whether it's something totally new, or something old seen in a new way.  We only have to keep our minds open and our senses alert, and pick up things from our own experiences, from other people's, from anything and everything around us.