Molecular Clouds

The Birth of Light

By: Alexandra Heater

What is it?

A molecular cloud also called a stellar nursery is a cool dense clump of molecular gas. A molecular cloud is made up of dust grain and is opaque. A stellar nursery has no defined boundaries and can take on different shapes depending on the other forces the cloud faces. Stellar formations that are very large can be scene by the naked eye. An example of one visible by the naked eye is the Coalsack in the southern sky which appears as a darker patch on the brighter Milky Way background. Stars are formed in molecular clouds (stellar nurseries). The composition of a molecular cloud is mainly made up of Hydrogen and Helium molecules with bits of other matter particles. A size of a molecular cloud will vary but some of the largest ones are a million times more massive than the sun. The molecular cloud is able to fight against gravity by using turbulence and the internal magnetic field to support it. The center of a molecular cloud is vary cold temperatures can range from -263 to -223 degrees Celsius. The clouds usually do not radiate their own light and appear very dark when viewed from an optical telescope.

Where are they?

Molecular clouds are found all across the Universe. Some examples are:

  • The Pillars of Creation-they may already be destroyed as what we are seeing through the telescopes is what happened up to 6000 years ago, we are seeing things fro so long ago because they light from that molecular cloud takes so long to travel to earth

  • A cloud in a main spiral of the Milky Way Galaxy called the Perseus Arm-this molecular cloud creates stars eight times as large as our sun

  • R136 that resides in the 30 Doradus Nebula-is the largest star nursery that is close to us, and creates icy blue stars which are the largest know stars in the galaxy

  • The Orion Molecular Cloud Complex-is about 1300 light-years away

How is is formed, destroyed, and Who first discovered it?

A molecular cloud is formed over a long period of time as different dust particles, debris, and hydrogen and Helium atoms combine to form a dense cold cloud. As the cloud forms stars the solar winds given off by the new stars slowly erodes the cloud. As the winds and shockwaves destroy the cloud they also compress new clouds together, helping people believe that a new molecular cloud will be created.

They were first discovered by William and Caroline Hershel in the lare eighteenth century. They discovered it by using visual telescopic observations. A century later photographic evidence taken and molecular clouds were officially established.

Who discovered what it truly does?

Nasa truly discovered the importance of a molecular cloud because before the Hubble telescope we were only able to see them as darker spots in the sky. Now using Hubble's infrared light we are able to see the clouds in an astonishing new light. With these new photos scientists were able to understand how the cloud works. Molecular clouds create stars, but in order for the formation of a star to begin the cloud must first collapse a little on itself and increase in density. There are two ways a cloud can begin to collapse one way it for it to collide with another molecular cloud. The other way is for the cloud to be near enough to a Giant SuperNova to encounter its pressure. Once the cloud has been condensed enough a star can begin to form. When two clouds collide many stars can be born not just one or two at a time.

Why they are important

Molecular clouds are not just things of beauty. They are a vital part of our universe, as they begin the life of new stars. The birth of a star has around 3-6 different stages. At first the molecular cloud begins to form little clumps within the cloud itself. Gravity will then come into action along with another exterior force and start condensing the cloud, while being condensed slight rotation becomes amplified and forces in falling debris into a disk. As the cloud condenses the core of the cloud becomes super heated. In the super heated core a protostar begins to form. A protostar is the early stages of star formation and occurs before nuclear fusion can begin.
Eagle Nebula - Pillars Of Creation And Destruction

The forming of a Star

The below picture shows the main sequence of a star forming, and proves why molecular clouds are important.

  • Starts with a molecular cloud( Without the cloud there would be no stars at all)
  • Then gravity collages that part the cloud
  • The cloud starts to flatten into a disk shape, while a prostar is formed in the heated core
  • The prostar becomes a ful fledged star, and the disk around the star stars forming protoplanets
  • The protoplanets begin to collect more debris and form their own orbits around the star
  • The new stellar system is born, with plants orbiting the star

Big image

Research Log

May 7th

  • what molecular clouds are made of
  • what they do
  • the basic parts of a molecular cloud
  • how they are created

  • learned of the Pillars of Creation
  • tells of how dense they molecular cloud is
  • How the pillars and other molecular clouds can be destroyed
  • what we see is what happened 6000 years ago

  • Bok Globules (another name for molecular clouds)
  • multiple stars can be born in a core
  • appear as dense clouds darker than the stars when looked at with the naked eye

  • the size of molecular clouds
  • gravity is the force pushing the cloud together
  • the core heats up as gravity forces inward
  • a prostar is created and the part of the cloud will start to spin
  • Nuclear Fusion is the force keeping the star from collapsing

May 16th

  • photo of the Orion Molecular CLoud Complex
  • that it is indeed a molecular cloud
  • it is 1300 light years away

  • also called a dark nebula
  • the clouds are opaque
  • they are visible to the naked eye
  • Coalsak Molecular cloud
  • the clouds magnetic field support its from the affects of gravity

  • R136
  • the largest star nursey near by
  • produces the largest stars which are blue
  • photo of R136
  • They stars will "pop-off like a string of firecrackers in a few million years"

May 18th

  • they are also the birth place of planets
  • the clouds are very cold to start of having a temperature of -263 to -223 degrees Celsius
  • infrared rays can see through the cloud
  • The Hubble space telescope first used infrared lights to view molecular clouds

  • example of how the pillars are being destroyed
  • why they are in the shape of pillars
  • the spitzer space telescope took photos of the pillars

  • William and Carol Hershel first discovered them in the sky in the eighteenth century
  • the real first photo was taken by Barnard in the nineteenth century
  • clouds are majorly important as they formed all the stars in our galaxy

May 19th

  • how the clouds first start creating stars
  • they either collide
  • or the pressure from a supernova helps the cloud first start forming clouds
  • several stars can be formed at a time

  • Perseus arm photo
  • It is one of the milky way galaxies spiral arms
  • creating stars eight times larger than our sun

Citations in MLA format

Anissimov, Michael. "What is a Stellar Nursery? ." wiseGEEK. N.p., n.d. Web. 7 May 2013. <>.

Astrophysical Journal Letters, . "Milky Way's Vast Molecular Clouds --Creating the Chemical Precursors of DNA." dailygalaxy . The National Radio Astronomy Observatory, 1 May 2013. Web. 18 May 2013. <>.

Blake, Leesa, et al. On Science 9. Canada: McGraw-Hill Ryerson Limited, 2009. Print.

Brill, Richard. "How is a star born?." Scientific America. Nature America Inc, 6 Dec. 1999. Web. 7 May 2013. <>.

Cain, Fraser. "How Does a Star Form." Universetoday. n.p., 26 Jan. 2009. Web. 19 May 2013. <>.

Greg. "The Orion Molecular Cloud Complex." Outerspaceuniverse. N.p., 14 Jan. 2010. Web. 16 May 2013. <>.

Harvard-Smithsonian, Center. "Bok Glodules." Physorg. N.p., 4 June 2010. Web. 7 May 2013. <>.

Keller, Jim. "Molecular Clouds." Cool Cozmos. n.p., 18 Oct. 2011. Web. 18 May 2013. <>.

Lada, Charles J. "Molecular CloudsNear-Infrared Extinction and Molecular Cloud Structure." ifahawaii. n.p., n.d. Web. 18 May 2013. <>.

Mathis, John S. "Molecular Cloud." Brittanica, 2009. Brittanica. Web. 16 May 2013. <>.

Nosowitz, Dan. "Unbelievable Hubble Shot Captures the Biggest "Star Nursery" Nearby." Gizmodo. Gawker Media, 15 Dec. 2009. Web. 16 May 2013. <>.

Smith, Stephen. "Crumbling Pillars." Thunderbolts. N.p., 21 Nov. 2012. Web. 7 May 2013. <>.

+A youtube video with the link-