HowDoWhy

The Sun is about 4.57 billion years into its main-sequence stage and when we think of its age, that’s the number generally agreed on. You can think of this as the relatively stable period in a star’s life after it forms and during which it converts Hydrogen into Helium in a process known as nuclear fusion. Scientists estimate our star is about half-way through its main-sequence stage. In a little more than 5 billion years from now and once most of the Hydrogen in its core has been converted, the Sun will enter its next stage of evolution, its red giant stage.

During the Sun’s red giant stage, it will swell in size until it is bigger than the Earth’s orbit. Life will have long since died on Earth before this happens. In fact, the sun is warming more and more even now. Some estimates hold that life will be impossible on Earth due to solar heat in less than 1 billion years! Don’t worry, though, that’s plenty time for us all to move a little further out to Mars and maybe even to other stars! While in its red giant stage, the super-hot core of our star will burn Helium and convert it into Carbon.

After its red giant stage, the sun will begin to cast off its outer layers in a spectacular show, forming what’s known as a planetary nebula. The picture to the left was taken by the Hubble Space Telescope and shows a planetary nebula designated NGC 6369: The Little Ghost Nebula.

After completing it’s red giant stage and casting off its outer layers, what will be left will be a white dwarf.

If you’re ever away from the glare of city lights on a cloudless night, take a look up into the sky and marvel at the countless thousands of sparkling stars you see up there. Pick one you like and point your finger at it. Now imagine that maybe, just maybe, the star you’ve picked has a planet orbiting it and a boy on that planet is looking up into his night sky and pointing right back at you, because the Sun is really just a star! To that alien boy on that alien world orbiting that alien star, our sun is just one of a countless number of twinkling stars in the sky.

As stars go, ours isn’t particularly special. It isn’t a super-giant. It isn’t a pulsar. It doesn’t have enough mass to explode in a giant super nova when it dies. Our star is categorized as a Yellow-Dwarf and its composition is made up primarily of Hydrogen (about 74% by mass), Helium (about 24%) and trace quantities of other elements make up the remainder. It does have some things to be proud of, though. For one, it is a 3^rd generation, Population I star meaning that it likely formed as the result of an older star’s death (in the form of a super nova) and it’s solar system is, therefore, comparatively rich in heavy elements (gold, iron and other important stuff without which human technological advancement might have been a real challenge).  

Our Sun is also fairly even tempered. It throws a tantrum now and again and tosses material around the solar system, but, for the most part, the Sun has remained a calm and nurturing mother to the planetary children that circle around her. Without the relative stability of our local star, life couldn’t have formed on the Earth! And that’s the third thing our star can be proud of - it hosts a planet that harbors intelligent life. Not bad for a little yellow dwarf in an obscure arm of the galaxy.

My apologies for the dearth of posts last week; it was crunch time at the office. I did manage to get a few in about dolphin sleep, Apollo 11 and the Moon and hope you enjoyed them. This week I hope to stick to a specific topic.

I’m the proud uncle of a highly intelligent boy named James whose enthusiasm for science is simply astounding. I know it’s fairly common for parents and uncles gush about how bright a child may be but no fluff here, folks. This kid is smart! He loves cars, trains and dinosaurs, as do most kids his age, but he also has a strong interest in science and astronomy (I believe he was only 5 when he explained that planets like the Earth aren’t perfectly spherical but tend to bulge along their equators).

So, in honor of James, today kicks off the start of a week or more of astronomy-focused posts beginning with our closest star, the SUN!

Today, the average distance to the moon is 238,856 miles.

There are two interesting things to note in that answer. First, note the word “average.” Remember that the Moon’s orbit is elliptical and not perfectly circular so the distance varies by as much as 26,000+ miles. To put that into perspective, the distance of the Moon to the Earth varies by more than the actual circumference of the Earth at any given time!

The second thing you should note in that answer is the word “Today.” The Moon is slowly leaving us at a rate of about 3 ¾ centimeters per year. That doesn’t seem like much but it will be a different sky up there in another million years or so. The thing to note is that, as the Moon recedes, the Earth’s rotation slows. If we’re still around a million years from now, our progeny will envy us the “short” work hours we enjoy today.

If you wanted to drive to the Moon (and somebody bothered to build a road) at a comfortable 60 miles per hour, it would take you just shy of 3981 hours or almost 166 days to get there. No rest stops along the way so everybody hit the bathroom before taking off!

Walking to the Moon at a man’s average of 3.5 miles per hour would require a trip of 68224.5 hours or 2843.5 days or almost 7.8 years (assuming you never stopped to sleep or eat).

If you’ve ever wondered Why is the Moon bigger on the horizon we’ve gladly already answered the question in an earlier post and invite you to read all about it.

You can also read more about the Moon at http://www.jimloy.com/astro/moon0.htm

The first man to walk on the moon was Neil Alden Armstrong followed immediately by fellow Apollo 11 crewman, Edwin Eugene ‘Buzz’ Aldrin, Jr. on July 20, 1969. While most folks know of Neil Armstrong and many recognize Aldrin as Buzz Aldrin, few know that a 3^rd astronaut accompanied the men and remained in orbit piloting the Command Module. His name was Michael Collins and we can thank him for the safe return of Buzz and Neil to Earth. He’s also credited with a space flight on the Gemini 10 mission where he performed two EVAs (Extra-Vehicular Activity) or space walks. Three missions preceded Apollo 11 to the moon though Apollo 11 was the first to actually land with human cargo. Apollo 8, 9 and 10 were sent to fly orbital missions around the moon.

Nearly as well known as the Apollo 11 mission, Apollo 13 was to have been the third manned moon landing. The mission was aborted after a crippling explosion due to a fault in an oxygen tank. The heroic crew - James Lovell, John Swigert and Fred Haise successfully returned the limping craft to Earth thanks to incredible efforts on both their parts and mission support personnel at NASA, but had to abandon the actual moon landing. Apollo 13 shares its place in history as the 2^nd of two manned moon missions that brought the world together in breathless anticipation, prayer and hope. Touted as a “successful” failure, Apollo 13 still serves as an inspiration and a testament to human ingenuity.

The final manned mission to the moon was the Apollo 17 mission - December 7 - 19, 1972. Apollo 17 was the 11^th manned space mission of the Apollo program. Crew for the mission were - Eugene Cernan, Ronald Evans and Harrison (Jack) Schmitt. Cernan is credited as the last man on the moon. His final “official” quote was - “As we leave the Moon at Taurus-Littrow, we leave as we came, and God willing, as we shall return, with peace and hope for all mankind. As I take these last steps from the surface for some time to come, I’d just like to record that America’s challenge of today has forged man’s destiny of tomorrow. Godspeed the crew of Apollo Seventeen.”

But the actual last words spoken from the surface of the moon were not to the people of America or Earth but by Cernan to Lunar Command Module pilot, Jack Schmitt. “Okay, Jack. Let’s get this mother outta here.” - Cernan seconds before lift-off.

From Apollo 11 to Apollo 17, six successful moon landings were launched and retrieved with no loss of life. The Apollo program still stands today as one of mankind’s crowning achievements. On a personal note, metaphorically speaking, we left our safe shores and cast ourselves into dark and mysterious waters to land on another island, another world, impossibly distant from ours. Since the return of Apollo 17, we’ve not again left the beach. In 36 years, we’ve gone from brave explorers to cautious children, barely dipping our toes in the lapping waves of an unknown and beckoning sea. As tragic as the loss of spirit may be, there is also a hidden price to be paid. Should we ever find ourselves longing for the stars and alien worlds again, we’ll have to start from scratch. The infrastructure and practical applied knowledge that got us off one rock and on to another has been left to waste away. It costs a lot to start from scratch in terms of money, time and, I fear, lives. Such is the price of America’s fickle and wandering attention span. When Cernan spoke his last quote about man’s journey, “…for some time to come…,” could he possibly have believed it would be so long a hiatus?

 Yep! Dolphins and whales are mammals and all mammals sleep. Aside from living in water, one of the things that distinguishes us from our aquatic cousins is how we breathe. Humans don’t have to think about breathing. You can, if you choose, hold your breath or elect to inhale or exhale. But if you stop thinking about breathing, you’ll still go right on doing it even when you’re completely unconscious or asleep. We are unconscious breathers.

Dolphins and whales differ from us in that they are conscious breathers. They choose when to breathe at all times. It’s an important distinction. Imagine if you were to doze off underwater. Eventually, your body is going to inhale with disastrous results! The same would happen with dolphins and whales if they weren’t designed to breathe consciously.

Now if you’ve put two and two together, you have probably concluded that sleeping is the same as being unconscious so how could a dolphin possibly sleep if it has to consciously breathe?! It’s a neat trick of nature.

A dolphin sleeps half a brain at a time! That’s right, dolphins or whales will shutdown one hemisphere of their brain during “sleep” and repeat the process with the other half later. They will tend to remain near the surface while doing so to minimize effort in breathing. During these rest cycles, they are likely in a semi-conscious state much like we are shortly before we truly fall asleep. They can still rapidly wake up, respond to external stimulus and react to danger if needed unlike us when we’re completely asleep.

An interesting note on dolphin sleep - Just as our experts have been suggesting to us for years, dolphins spend about 8 hours a day in their sleep state. If it’s good for Flipper, it’s good for you!

 Yes they do… sort of! How, when and where depend on the fish and what you define as sleep. First, fish lack eyelids so they don’t shut their eyes and doze off like we do. Second, what humans define as sleep involves a significant change in brain wave activity which doesn’t seem to occur in fish. But fish have periods of activity and inactivity and they appear to be recuperating during those inactive periods just like we do when we sleep.

Many fish seem to rest very lightly, sensitive to the slightest change in the water. Others are real dozers. I’ve actually held a slime-covered parrot fish during a night dive and that guy was out like a light! Some fish nest in cracks and holes in the reef or rocks. Others will sleep on the bottom. Any aquarist who owns a clown loach might relate their initial panic on finding the fish on its side, seemingly sick or dying. But once stirred by light or activity, the fish perks right back up. It was sleeping!

Some fish, including many species of shark, must keep moving to pass water over their gills to breath. It is suspected that these animals experience lowered or altered levels of brain activity that allow them to rest. It’s not unlike the autopilot experience you might be familiar with in which you’ve driven 20 or 30 miles on a major highway but weren’t really consciously aware of the act.

Kathleen of Virginia submits another one!

There are so many great resources on this subject that I won’t bother reinventing the wheel and will provide you a few links to all the information you could ask for, but to summarize, autism is a neurological disorder that strikes an average of 3-6 children out of every thousand. Characteristics common to children and adults suffering from autism include poor social interaction skills, difficulty with verbal and non-verbal communication, and repetitive or very limited activities or interests. Common indicators in diagnosis include:

• Impaired ability to make friends with peers
• Impaired ability to initiate or sustain a conversation
• Absence or impairment of imaginative and social play
• Stereotyped, repetitive, or unusual use of language
• Restricted patterns of interest that are abnormal in intensity or focus
• Preoccupation with certain objects or subjects
• Inflexible adherence to specific routines or rituals

Recent concerns of a link between the MMR vaccine and autism have been largely discredited as the result of two major studies. Though the subject is still very much under scrutiny, there are indicators that hereditary factors play a part in autistic development. For example, identical twins and fraternal twins are both likely to be exposed to the same environmental influences and follow the same vaccination schedules but incidents of autism in both children is more common with identical twins than with fraternal twins. This implies a genetic cause rather than a foreign substance, event or environmental source.

Another concern that autism cases appear on the rise is suspected to be linked to the adoption of a broader categorization of autism rather than an actual increase in cases. To clarify, where a child might once have been considered a little “odd” or “off” a few years ago, today their behavior might be more readily attributed to autism.

Two great resources I’ve found that discuss Autism in great detail (and served as sources for this post) are:

The Autism Fact Sheet provided by the National Institute for Neurological Disorders and Stroke is a great resource. Don’t let the big title scare you off, the documentation is clear, concise and very approachable.

Also read the great write-up in the New York Times Health section - Autism.

For support, visit MDJunction. Their Autism Support Group brings together families coping with autism.

Update! 4/21/08 - An interesting article on MSNBC discusses recent successes with virtual reality and autistic children.

Spring is finally here and grills across America are beginning to fire up. The mouth-watering smells of burgers and hotdogs filled my own neighborhood last weekend, but the smell that always sends me running to the grocery store is the smell of grilling steak. I have very high expectations when it comes to steak and it’s a rare treat to reproduce the results I’ve experienced in some of the best steak houses in America. No wonder, as grilling an awesome steak is as much art as science and there’s a surprisingly significant amount of science as it is. So let’s get to it!

In the steak grilling world, a perfect steak has four main elements.

• Taste
• Visual Appeal
• Doneness
• Texture - Tenderness

Miss out on any of the above and what could have been the perfect steak winds up as only a good or ok steak. Miss more than one and it can be a disaster. Taste is largely a combination of the type (cut & grade) of steak you buy and the rub or seasoning you use. Visual appeal is fairly simple to accomplish and I’ll touch on it in a later “quick-hit” post. A steak cooked to preference is a real challenge and a topic for a lengthy future post. Today, I’d like to talk about Texture. So if you’d like to learn how to cook a wonderfully tender steak (as well as learn what not to do) please read on! Continue reading »

This question was submitted by Kathleen of Virginia. Thanks, Kathleen!

Much like the tallest building, determining the biggest insect question is challenging in that it really all depends on how you define biggest. Do you want to know what the longest insect is, what the heaviest insect is or what the bulkiest insect is? Biggest bug, unfortunately, leaves room for speculation. Since I don’t know what you define as “biggest” I’ll give you the best answers I can find.

Weight - The overall mass of an insect is what your average entomologist would probably consider the real criteria for the size question. The record holder there is the Goliath Beetle, a member of the Scarab family. While this insect only grows to be about 4.5” long, their sheer weight makes them a top contender for the “Biggest” prize at 100 grams (more than a small bird). The picture to the left, from ExtremeScience.com, is of a Goliath Beetle clinging to the forearm of an ADULT MAN! Visit ExtremeScience to read more about these harmless and important creatures as well as a lot of other interesting topics!

Not as heavy (71grams), the still massive New Zealand Weta is also deserving of mention in the Mass category. For some great pictures of the Weta, visit http://nzphoto.tripod.com/animal/weta.htm

Bulk - Often mentioned as one of the “largest” insect, the Acteaeom (or Acteon/Actaeon) Beetle often receives an entomological nod of approval. This thing takes up a lot of space! 5.3 inches long by 2 inches wide and 1.5 inches thick, it isn’t as heavy as the Goliath nor as long as our next contender, but for overall space occupied, it’s certainly worthy of mention. Cute looking fella, isn’t he? You can see more great pictures of this notable giant at http://www.goliathus.com/en/en-megasoma-actaeon-actaeon.html including some great close-ups!

The South African Longhorn beetle is our next honorable mention at about 6.3 inches in length. It’s not as bulky as the Acteon but I imagine most of us would pay it a fair amount of respect if we woke up to it crawling on us. Thanks to ScienceBob for this great picture. A bug in the hand is worth… well I don’t know what it’s worth but my skin is crawling.

Wingspan - The largest wingspan recorded on a bug is a fossilized dragonfly with a wingspan of over three feet!

Our last candidate isn’t bulky nor is it massive, but I think you’d still call it big if you saw one!

Length - The Giant Walking Stick insect is our winner for length. It would probably lose a wrestling match with any of our previous contenders, but it’s the bug you’d want to call if you ever needed something from the top shelf. They can grow up to 20 inches in length!