Exoplanets

For a long time, man has pondered the existence of planets elsewhere in the universe. It has now been accepted that they do exist beyond our solar system, we now have the technology to observe them. These planets orbiting alien stars are known as exoplanets, and they are a hot topic in today's scientific world.

The majority of stars, at least in our galaxy, could host exoplanets.

So far we have identified somewhere around 760 planets outside of our solar system, with over 2,000 still awaiting confirmation. Almost everywhere we look we are discovering new planets, they seem to be very commonplace. From the data collected so far, it looks as though there could be as many as 1.6 planets per star, which means that there are around 160 billion exoplanets in our galaxy alone. That number is staggering, especially when we consider the size of the objects we're talking about. Now remember, planets appear to outnumber stars, just try counting all the stars.

  There are countless stars in the night sky.

Most of the exoplanets we've identified so far are exceptionally large, often gas giants, but this is due to a bias in our observation techniques. New information indicates that small, rocky worlds, much like earth, are actually far more common. The reason that we see the larger planets better is because they have a bigger impact, let me explain. There are two common methods for identifying planets, transit photometry and radial velocity. Transit photometry waits for a planet to pass in front of its star, then measures the dip in light, allowing us to not only get a feel for the size of the planet, but also a reading on what its atmosphere is comprised of. Larger planets are obviously favored with this technique because they make bigger, and thus more easily detected, dips in light. The other method, radial velocity, looks at the "wobble" in a star's motion. A planet orbits a star because it is being pulled by that star's gravity, but the planet's gravity also has an equal pull on the star. Because of their comparative masses, a star's planet doesn't have much of an effect, but it can be large enough for us to measure, giving us another technique for identifying exoplanets.

Kepler-10b, the smallest exoplanet yet identified.

There exist several more methods for identifying exoplanets, but the two I've described are by far the most common. Most exoplanets cannot be viewed directly with a telescope, they reflect very little light and the glare from their parent stars usually washes them out. However, even given the obstacles, some exoplanets have been observed directly, usually appearing as tiny dots.

The little dot near the top of the image is the planet.

An exoplanet is usually viewed through the infrared spectrum when being observed directly because it reduces the glare from the parent sun.

Many questions still remain about exoplanets. Much of the search for bodies beyond our sun has been focused on finding suns like our sun and planets like our planet, all in the hopes of finding life beyond or tiny sphere. We don't know under what conditions life can exist, but we have a pretty good idea. The jackpot of exoplanets would be nearly the size of earth orbiting it's sun in the habitable zone, the golden area where the planet isn't too hot or too cold, just right for the existence of water. So far, all of our experience says that life needs water to exist, while this isn't necessarily true, it's our best guess when looking for life. If all goes well, we might just find the perfect planet. We'll all just have to cross our fingers and hope.

If a planet is too close to it's sun, it will not be able to sustain life.

 

Inside a Black Hole

I highly recommend watching this video. It tells us a lot about what would happen if you were to travel into a black hole, plus it goes further to explain the expansion of the universe and light speed. It's all really cool stuff.

Micromachining

Check out this link that demonstrates how micromachining can be used to create tiny robotic devices. I found it fascinating.

Fluoride

Fluoride, usually you hear this word when talking about dental health, but that's not strictly what it means. Fluoride is technically an F- anion, but not everyone is referring to this particle. Fluorine is capable of bonding with almost every element, so it can make a wide variety of compounds, ranging in use from pesticides to cavity prevention, they can be toxic or medicinal, highly reactive or entirely neutral. Fluoride could easily reference any of these multitudes of compounds, but that's not what I'm here to talk about.

Fluorine gas

Fluoride is used to help protect teeth from erosion. It's fairly simple, when a fluoride compound is ingested by, or otherwise applied to, a person it dissociates (breaks apart) leaving the lone fluorine ions. These ions are then absorbed into the enamel (the tooth's protective outer coating), where it reinforces that tooth, protecting it from decay. In everyday life, a person's teeth will experience both demineralization and remineralization. This means just what the words suggest, minerals are constantly being leeched from the teeth and replenished. Acids from plaque bacteria and sugars will begin to destroy the enamel of a tooth, causing the tooth to decay if these minerals aren't properly replenished. That's why fluoride is so important, it helps to replenish the enamel and protect it against further destruction.

Structure of the tooth

 

Fluoride is heavily used by dentists and health care professionals as a preventative measure against cavities, especially for young children. Below the age of 6, ingested fluoride will go into the development of teeth, strengthening them for the remainder of the child's life. Professionally applied topical fluoride treatments usually consist of a mixture of sodium fluoride (NaF), acidulated phosphate fluoride (FH₃NaO₄P), and sodium fluoride varnish (NaFV). 

 Duraflor, a brand of fluoride varnish

Fluoride is so useful that it has been added to the U.S. water supply. Now most public water supplies contain between 1.2 and 0.7mg/L of fluoride. These fluoridated water supplies reach well over 70% of Americans. However, with this chemical being added to public water supplies, it hasn't always been greeted favorably. Many people feel that fluoride should not be added to public water. It infringes on a person's right to choice, and there are legitimate medical concerns.

 Most tap water contains fluoride

Like everything, fluoride can kill you. A fatal dose can be as low as 3 to 5 mg/kg. Now, given the weight of the average adult, you aren't likely to be hurt by this chemical, however, young children could easily be at risk. Even if it doesn't kill you, fluoride can still cause a condition known as fluorosis. When a person gets too much fluoride, usually while their teeth are developing, their teeth will develop discolorations and pitting. This can range anywhere from white spots to ugly brown blotches. While it may not be fatal, it certainly isn't fun to have.

 Bad case of fluorosis.

 

I am no medical professional, so I won't try to tell you if the fluoride in American water systems is a good or bad thing, but I can recommend that everyone be mindful of how much fluoride they are consuming. Perhaps a talk with your local healthcare professional wouldn't be a bad idea if you're curious, or you could always type "fluoride" into the Google search bar to find more information. There is a strong debate on the subject, a debate I'd like to stay out of.

Nebulae

You've probably heard of the Crab nebula or the Orion nebula, but how much do you actually know about what a nebula is? Nebulae are popular because of their unique beauty. The coolest images that always seem to appear when referencing space are images of nebulae, they truly are the defining beauty in the universe.

The word "nebula" is derived from the Latin word for cloud, and that's no coincidence. Nebulae are like vast clouds in space, ranging from dozens to even hundreds of light years across. They are made up of gases and tiny dust particles, deriving their magnificent light from their own radiation or by reflecting the light from stars. Most nebulae are about 90% hydrogen, 10% helium and 0.1% other heavier elements including anything from carbon to iron.

 

The Triangulum Emission Garren Nebula  (NGC 604)

Nebulae are classified into five different types: emission nebulae, reflection nebulae, dark nebulae, planetary nebulae, and supernova remnants. Emission, reflection and dark nebulae are all classified under diffuse nebulae because they all have similar compositions and tend to be fuzzy, lacking any specific shape.

Emission nebulae are made up of high temperature gases, mostly ionized hydrogen, that emit red light. Stars that are sometimes hidden within the nebula energize the gases and cause them to emit this light. They work a lot like neon lights, energy is applied to a gas which releases that energy as light.

 

 Orion nebula, an emission nebula, actually visible with the naked eye

Reflection nebulae have the same composition as emission nebula, but instead of being hot and radiating light, they are cold and usually reflect light from a star or cluster of stars. Much of the light from reflection nebulae is blue because it reflects better. Reflection nebulae are some of the better places for star formation because of their relatively low energies.

 The Trifid nebula, a reflection nebula

Dark nebulae, classified under diffuse nebulae with emission and reflection, have the same sort of composition as their brethren, but instead of reflecting light, their position means that they block light.

 Horsehead nebula, a famous dark nebula

Planetary nebulae, despite what their name might suggest, have nothing to do with planets. As a star begins to die or turn into a white giant, they will leave a shell of gas. These nebulae used to be mistaken for planets, hence the name. Planetary nebulae have the same composition as diffuse nebulae, but much more dense.

 The Ring Nebula, a good example of planetary nebulae

And finally, supernova remnants. These nebulae are exactly what their name would suggest, remnants of supernovae. When a star dies, it spews out large amounts of gas and debris which can glow from their own supernova energy or be illuminated like diffuse nebulae.

 The Crab nebula, a supernova remnant

There is a saying that nebulae are stellar nurseries, and this is exactly true. All the stars and planets in our universe were likely created in nebulae. A nebula can sit undisturbed for thousands of years, but if a shock wave from a supernova or any other event disturbs it, there will likely be a cascading event. Particles begin moving closer to each other and adhering because of gravity. Eventually they will form clumps that reach critical mass, where gas and particles begin heating up due to pressure and friction enough that they ignite, creating protostars. The remaining matter can often coalesce into planets or other space rocks. And thus, a new solar system is born.

And now for some cool pictures.

 The Pillars of Creation

 The Eagle Nebula

  The Flame Nebula

And my favorite:

 The Carina Nebula

Is there such thing as a jellyfish?

I've found this rather interesting clip from the Monterey Bay Aquarium Research Institute. It details the evolutionary tree of various gelatinous creatures living in the ocean. I recommend checking it out, I find it fascinating.

http://www.youtube.com/watch?v=3HzFiQFFQYw&feature=player_embedded

Carina Nebula

Of all the sights in the universe, the Carina nebula is by far one of the most spectacular. This nebula, spanning 50 light years, lies a daunting 7,500 light years from earth. But even at this great distance, it continues to be a breathtaking phenomenon to behold.

This is a full image of the Carina nebula

The large bright spot near the middle of this image is Eta Carinae, a hypergiant star.

These pillars of gas and dust are resisting erosion from stellar winds.

The glowing "caterpillar" to the right is a globule of cold dust and gas that is illuminated by stellar radiation.

For more concerning the Carina nebula, I would recommend visiting Hubblesite.org and going to their image tour.