My Outlook on Astronomy and the Universe

My eyes have been opened even more to the universe of astronomy.  It seems to be the topic that is known the least by mankind and definitely needs more time invested into it.

I have always been curious of what else is out there.  There, in the worlds beyond our own and even farther.  Infinite is an insane idea to comprehend; after all, it is hard to understand something that cannot actually be seen.  Will the universe keep expanding into what seems like an infinite void?  What lays beyond the edge of the universe?

I have my own theory about how the universe acts.  I believe that it might be possible that the universe is expanding onto or into itself and that as it expands it also retracts.  It is caught in a loop.  Perhaps it could be compared to a mobius strip, such that it continues and there is never an actual end.  Or, imagine holding a malleable object (perhaps silly putty) in your hands.  Form this object into a ball.  Then push in the middle of it with your thumbs so that the ends would bend up.  Then push those ends into the hole you created and repeat.  This theory suggests that the universe will collapse onto itself and continue to grow after.  As a result of this we might end up seeing stars get closer instead of farther from us.  The reason that we might not have seen this yet is because of the long period of time it takes for this cycle to occur; however, like I said it is just a theory.  Even if this theory is correct, it still does not answer the question, what is the universe encompassed by?

Astronomy is an exciting subject to discuss because of the theories that can be formed from the unknown topics of the heavens.  There might be something out there that we have yet to even imagine.  Whether it is aliens or other planets, the universe is a extravagant place and will always keep me curious as to what is out there.

As you sit "stationary" there reading this, the earth is moving through space at a spot that is infinitesimally small in comparison to the rest of the universe.  It is amazing and maybe even scary to think we are so small.  There is so much out there!  And one day, maybe we will see what we have been missing.

Filling In The Empty Space

What seems to be a large amount of space with nothing in it is actually full of dark energy.  The vast universe is full of celestial bodies and objects and dark matter but dark energy accounts for about 73% of the rest.  With so much in existence, how do we know so little about it and why?  Such a peculiar idea that something of such quantity can even exist.

 (pie chart comparing dark energy to the rest of the universe, image from http://opentheory.net/)

Albert Einstein (once again) was one of the first to speculate that the "empty" space outside our world was not actually empty, but instead there is something rather than nothing.  This existing dark energy has a great affect on the universe.  Alternate to the assumption that the universe is expanding and slowing down, dark energy is theorized to cause the universe to expand but instead be speeding up!  This can be a consequence of the increase in space.  As more volume is created with the expanding universe, there is an increase in dark energy causing an increase in acceleration of expansion.  Seems unreal considering that if it is creating virtually an infinite amount of dark energy, how fast could the universe actually be expanding?  Perhaps faster than the speed of light?  Only furthering studies on dark energy could answer these questions; after all, our knowledge on dark energy is more unknown than it is known.

Of course, as with many physics topics, that is just one theory of dark energy.  Another is that there are virtual particles that are said to "pop" or appear in and out of existence in space.  This assumption seems quite strange in that it doesn't explain how a particle can just appear.

The cosmological constant (often distinguished by the capital form of the Greek letter lambda) is another term used in the theory of dark energy.  This constant is the fundamental energy of space, homogeneously filling in the "emptiness".  It has been estimated to have a density value of ten to the negative 27 power (g/cm^3).  Through thermodynamic discussion, the cosmological constant has a negative value of pressure equating to the energy density (rho).  A consequence of this is the acceleration of expansion.  Expanding changes the volume, causing a negative pressure, since for an isochoric (or isovolumetric) system work = - pressure * change in volume.  The energy is equal to rho * volume and therefore pressure = - rho or vice versa. 

Dark energy is an amazing substance that hopefully can be used in the future to benefit mankind.  Just as we use the knowledge of gravity to understand how many things work, maybe we can harness the idea of this somewhat new concept to extend our comprehension of our universe.

 (picture to show vast amount of "empty" space, image from http://www.windows2universe.org/earth/earth.html)

Neighboring Galaxy

To think that there is more outside of our own planet is strange enough, but to think there are whole other galaxies is just ridiculous!  The Andromeda Galaxy is our "neighboring" galaxy; it is the closest major (or large) galaxy to us.  Our home part of the Universe is the Milky Way Galaxy and a couple million light years away is the Andromeda Galaxy.

(Actual picture taken by Robert Gendler, image from http://www.pbs.org/seeinginthedark/astronomy-topics/andromeda-galaxy.html)

Andromeda is a spiral galaxy (as shown above), similar to ours, rotating in free space.  Often referred to as M31 (or Messier 31, named after astronomer Charles Messier), it contains about 1 trillion stars, a number seemingly impossible to understand.  This is a vast amount more than we have in our own galaxy.  The Andromeda Galaxy is so bright it can actually be seen with the human eye at night, if you know where to look.


Astronomers have attempted to measure the dimensions and gather other statistics about this galaxy for a long while.  Recently scientists have used an eclipsing binary star of the Andromeda Galaxy to find the distance to Andromeda.  The binary star is a system of two stars that rotate around a central point (the center of mass) causing one another to eclipse each other from an outside reference frame.  Through this study, the sizes of the stars were found.  Combining this new data with the temperature of the stars, they found the distance to be a little over 2.5 million light years away.


The Andromeda Galaxy is quite large; it has a disk-like structure that extends a distance of 220,000 light years.  The structure of the galaxy is actually warped by the gravitational field of its own nearby (smaller) galaxies causing it to not be a perfectly flat spiral.  The mass of this enormous galaxy has been found to be 1.2 trillion times that of the Sun (solar masses), smaller than that of the Milky Way Galaxy (having a mass of 1.9 trillion solar masses), yet still a substantial amount.  At the center of this spiral there is an extremely dense cluster of stars that show a high level of luminosity.  The luminosity of the galaxy is estimated to be about 3.1e10 times that of our Sun.  However, with the increase in star formations of the galaxy, this number can vary.

(Picture of center of M31 showing high luminosity, image from http://www.universetoday.com/61779/andromedas-double-nucleus-explained-at-last/)

The Andromeda Galaxy is both beautiful and amazing; it is massive and bright, strange and mysterious.  Proof of this outstanding discovery brings the question, if other galaxies exist in our universe, what else is out there? 

(video from http://www.youtube.com/watch?v=HWxBTHVhc3I)

Astronomy Basics: The Solar System

For all you people out there who know tons about the solar system but perhaps forgot about the basics; this post is for you.

The solar system consists of many different celestial bodies.  From the Sun to Pluto, the solar system is quite vast.  Laying in the Milky Way Galaxy, the solar system is home to the gigantic star known as our Sun and a handful of planets which will be listed starting from the distance closest to the Sun.  The solar system has four terrestrial planets:  Mercury, Venus, Earth and Mars.  It is also home to four jovian planets:  Jupiter, Saturn, Uranus and Neptune.  Pluto used to be classified as planet like those listed but was retitled to be a dwarf-planet back in 2006.  Along with the planets and the Sun there are a variety of other objects wandering around space including the asteroid belt, located between Mars and Jupiter, and the moons of the planets.

 (Artist Rendition of the Solar System, image from http://scienceclass.ning.com/profiles/blogs/1677792:BlogPost:3140)

The Terrestrial Planets:  Mercury, Venus, Earth and Mars
These types of planets are made up of rock and/or metals and are usually referred to as the "inner" planets (closest to the Sun).  The main feature of these planets, compared to the gaseous ones, is that they have a solid surface.

The Jovian Planets:  Jupiter, Saturn, Uranus and Neptune
These planets are also called gas giants because of their composition.  Also known as the "outer" planets (farthest from the Sun), these planets are mostly  made up of hydrogen and helium.

Planetary Motion and Mechanics:
It is important to know how the planets behave as well as what they are composed of.  How the planets move in the solar system was theorized by Johannes Kepler.  He was a German astronomer who eventually created Kepler's Laws.  They are as follows:

1.  Every planet orbits the Sun in an ellipse.  The gravity from the sun causes the heavenly bodies to go around the Sun.

2.  A line drawn from the planet to the Sun will sweep out an equal area within an equal time interval.  This occurs because as the planets get closer to the Sun, they speed up.

(picture to illustrate laws 1 and 2, image from http://en.wikibooks.org/wiki/General_Astronomy/Kepler%27s_Laws)

3.  The orbital period of the planet squared is proportional to the semi-major axis cubed.  So the farther a planet is, the longer it takes to orbit the Sun.  It takes Neptune about 165 years to orbit the Sun, so no birthdays for any (if any) inhabitants on Neptune.

 -P = orbital period, G = gravitational constant, M = total mass, a = semi-major axis

(graph to illustrate proportionality of orbital period and semi-major axis of each planet, including the dwarf planet Pluto, image from http://www.windows2universe.org/the_universe/uts/kepler3.html)

It is always important when studying anything to understand the basic concepts behind what is being learned.  Knowing these facts will hopefully help you better grasp the knowledge of more complicated and detailed concepts of the solar system.

What's Out There?

With such a vast amount of area, it seems nearly impossible to know everything that is in our universe.  To help with this search the Interstellar Boundary Explorer (IBEX) has been finding neutral atoms out in space since 2009.  IBEX has found interstellar hydrogen, helium, neon and oxygen coming from outside the heliosphere.  Can these atoms from outside be any sort of proof of life beyond our own?  What else will IBEX find and will these findings change our future?

The heliosphere is where the solar system resides.  As a result of the solar winds from the sun, we are surrounded by this protective bubble.  The solar winds are made of charged particles that are able to escape the suns gravity because of their higher energy and temperature.  These solar winds create a cavity-like area that has been named the heliosphere. 

(Artist interpretation of the heliosphere among other things; image from http://www.centauri-dreams.org/?p=3763)

IBEX is the first to discover the interstellar neutral atoms (ISNs) hydrogen, oxygen, and neon (Ulysses discovered helium first).  These atoms are "blown" into the heliosphere.  The movement of the heliosphere and everything within (including the solar system) causes the interstellar atoms to be "blown".  The ISNs are unaffected by the magnetic field of the heliosphere and that is why the atoms are called neutral.

Consisting of only two sensors and a control for them the instrumentation that IBEX has is minimal compared to other spacecrafts.  IBEX has a Combined Electronics Unit (CEU) that controls the two sensors, IBEX-Hi and IBEX-Lo.  The atoms enter the sensors to be read by IBEX.  Upon entering, the atoms meet a filter-like instrument called the collimator which excludes charged particles and excess light that the IBEX does not want to analyze.  The two sensors evaluate the velocity of the atoms to figure out what the energy of each particle is and by using these energies the team can understand what the particles may be.

(IBEX Spacecraft; image from http://www.nasa.gov/mission_pages/ibex/IBEXMediaTelecon1.html)

With the discovery of ISNs scientists can better understand the defensive bubble that surrounds us known as the heliosphere.  This bubble keeps us safe by deflecting dangerous cosmic rays from our surroundings.  It is important to understand the things that protect us in order to maintain that protection if needed.  I believe that the data gathered from IBEX will expand our knowledge of the unknowns of deep space and help us answer many of the questions that have yet to be answered about where we came from and how.

LIGO!

The Laser Interferometer Gravitational-Wave Observatory (LIGO) has become an interesting topic with its research on gravitational wave.

Once again, Albert Einstein has proven to be quite the genius we all know him to be.  Einstein actually predicted that gravitational waves existed way back in 1916.  To find these ripples in space, scientists have constructed LIGO.  Together, the Massachusetts Institute of Technology (MIT) and the California Institute of Technology (Caltech) are working towards the mysterious discoveries of these gravitational waves.

The key component of LIGO is the laser interferometer.  This is the instrument that will be used to find the existing gravitational waves.  Below is a diagram of a laser interferometer:

 

(image from http://www.space.com/5221-scientists-expect-find-gravitational-waves.html)

This experiment needs high levels of precision and steady ground in order to not get excess noise in the data.  For precision,  a laser light is shot at the mirrors.  The laser is shot through a beam splitter to divide the light.  Each part of the beam travels separately down the two perpendicular arms of the system.  Each arm consists of two mirrors in which the light can bounce between them.  The two arms have the same length causing the beams to interfere and not be read by the photodetector.  For the photodetector to read any light, there would have to be some sort of change in the light beams.  Well there is something that does just that, gravitational waves!  The ripples of the gravitational waves causes the beams of light not to interfere and the photodetector is able to read light going through it. These ripples in space are caused by massive events such as collisions of the stars.

The LIGO team has sought out to find the gravitational waves for many years.  When the beam of light of the interferometer is altered and after data analysis, the team will know that they have found gravitational waves.

To get an idea of what the observatory looks like (the long arms are quite noticeable):

Livingstone, Louisiana

(picture from http://www.universetoday.com/46847/ligo/)

 Richland, Washington

(picture from http://www.ligo.caltech.edu/LIGO_web/0405news/0405liv.html)

More on the Moon: NASA's GRAIL Mission

Maybe you think that we know enough by now about the Moon and should focus on greater things that are still a mystery in our universe but there is much more to understand about Earth's massive natural satellite.  Being the biggest moon, relative to the size of its planet, this orbiting wonder is quite magnificent and needs to be studied more.

I find this mission personally interesting considering that the spacecrafts will attempt to understand the Moon's gravitational field and I have always found the force of gravity to be quite intriguing.

The Gravity Recovery And Interior Laboratory (GRAIL) Mission was designed to study the moon outside AND inside.  The GRAIL Mission consists of two spacecraft, initially named GRAIL-A and GRAIL-B, that will orbit the Moon to measure the gravitational field all around, including the side facing away from Earth.  From this information, scientists hope to better understand the structure and thermodynamics of the Moon.  The data gathered from this mission will also be applied to learning more about the terrestrial planets (Mercury, Venus, Earth, and Mars).  The spacecrafts will work together using the same instruments to obtain this data.

Below is a picture illustrating the mission at the moon:

(Picture from http://moon.mit.edu/overview.html)

Each spacecraft is about 440 pounds and have a Lunar Gravity Ranging System (LGRS) attached to it.  This device consists of four sub instruments that are used to measure the position of each spacecraft relative to the moon and one another and also transmits this data back to Earth. 

This mission was launched not just to learn more about the moon but also to get the public involved as well.  Each spacecraft is equipped with a few cameras for educational purposes only.  Schools and students can sign up to study the spacecrafts movement and also get pictures taken from the the spacecrafts.

The GRAIL Mission is just one of many missions made to study more about our own solar system.  There are also many other missions launched to learn more about the universe.  All of these missions are important to better understand this huge space that we humans occupy and how it came to be.  I hope that missions like the GRAIL Mission will forever continue to help answer our curious questions.

This is merely a summary of this great venture.  For more information on the GRAIL Mission click on the following links and enjoy:  http://www.nasa.gov/mission_pages/grail/overview/index.html, http://moon.mit.edu/overview.html