LIGO helping scientists understand gravitational waves

by Trevor DeBord

 

Image taken from Gravity Spy’s ‘about’ page

Gravity Spy is a crowdsourcing project which uses data taken from the Laser Interferometer Gravitational-wave Observatory (LIGO for short). LIGO was created in an attempt to detect evidence of Albert Einstein’s theory of general relativity. It is an extremely sensitive piece of equipment which detects gravitational waves from all over the universe. In fact, the LIGO is so sensitive that, “LIGO needs to be able to know when the length of its 4-kilometer arms change by a distance 10,000 times smaller than the diameter of a proton”(Information taken from Gravity Spy’s about page). A large amount of data is taken from LIGO, and Gravity Spy helps to categorize that data.

LIGO detects gravitational anomalies by shooting a laser down a pair of four kilometer long cavities and measuring the duration it takes for the light to reach each end. If the beams of light reach the end at different times, then we know there was some kind of interference. This can be caused by either a gravitational wave or some kind of external interference in the environment around the facility, causing a signal to be created. This works because the speed of light is constant, so LIGO acts as an extremely accurate timer measuring the change in the light.

 

A simplified version of how LIGO works. Image by: Jason Grigsby (Wolfram Blog)

Despite the scientists’ best efforts to reduce the possibility of common sources of interference by having two detectors separated by thousands of miles, glitches still occur often in both detectors. The ability to classify and filter these glitches is incredibly important for the development of this research, as it would increase the amount of legitimate astrophysical signal detection. This is where the crowdsourcing aspect of the research comes in. Participants of Gravity Spy will help to categorize a massive amount of data from LIGO, which will serve as a database for machine-learning. This machine learning will use this database as a way to classify new glitches based off what participants in the program categorized each specific glitch as in the dataset.   

A simplified version of how LIGO works Image by: Jason Grigsby (Wolfram Blog)

 

Overall I think the project is very interesting, and I will continue to do work on Zooniverse and Gravity Spy as time goes on. One of the things I specifically like about the project is the community behind it. There is an active forum where you can ask questions and post interesting things you found while working through it. I also like how there are occasional pop-ups which give you additional information about LIGO, giving you a better background.

 

Radio Galaxy Zoo and Black Holes

by Maritza Hernandez (a 2016 Adler Astro-Journalist)

Black holes are always found in the center of galaxies and we need help to discover them. There are two ways to find a black hole. One way to find a black hole would be by their gravitational influence. For example, we could find stars rotating around a black hole. The second way to find a black hole would be observing matter falling into the black hole. The more massive galaxies have bigger black holes in them, and generally the bigger the black hole is, the easier it is to locate. Bigger (more massive) black holes can eat more matter, and when a black hole eats matter it can create jets of material and those jets can travel close to the speed of light. You can detect these jets of material by a radio telescope than we can guess the location of the black hole.

On the Radio Galaxy Zoo site, they combine radio images with infrared images to find these black holes and their jets. Most of the radio images come from the Faint Images of the Radio Sky Twenty- Centimeters or for short FIRST, but also they come from the Very Large Array (aka VLA) telescope in New Mexico. The infrared images come from the Wide-Field Infrared Survey Explorer (aka WISE) and also the Spitzer Space Telescope. Radio images comes from the jets and the infrared comes from galaxies. Infrared is the color that dust glows bright in and of course galaxies have a lot of dust. Radio Galaxy Zoo needs your help to line up the images of the jets with the galaxies to help you to find a complete black hole system. But make sure that the jets look like they are coming from the black hole/galaxy.

We need your help to find these black holes! The Radio Galaxy Zoo team hopes that you can help astronomers learn how black holes are formed, how they are found, and much more. They try to use computers to find these black holes and their material jets. But what if the computers can’t do the job? Well, it’s hard for the computers to tell whether the jets are coming from a certain galaxy. Some other reasons that they want to find black holes are that we want to know what goes on inside of a black hole and why is it that time is affected by the black hole. We also want to know what role a black hole plays in unfolding the universe.

Galaxy Zoo: Classifying Galaxies

By Jenny Moore (a 2016 Adler Astro-Journalist)

Galaxy Zoo is a civil science project that teaches people about the different types of galaxies in the universe. There are ones with smooth edges, or swirl patterns, or ones that have undefined shapes. There can also be unusual qualities in the image of a galaxy, such as an odd pattern, or large center bulge. This project also teaches civilians that each galaxy is slightly different, just like a fingerprint! Throughout the project, one can discover how galaxies are formed, and what the astronomers connected with the project are trying to understand. Galaxy Zoo’s goal is to study different galaxies and understand how the formation of galaxies affects the universe around us. Over time, the interactive galaxy classifying ‘game’ has matured from just identifying the galaxy’s shape, to identifying its key features, and even using images from special cameras that measure dark energy!

Figure 1: Above you can see different examples of galaxies and the different shapes they come in.

 

This project has evolved and each stage gradually gets more complex for the civil scientists. Galaxy Zoo started with images collected from the Sloan Digital Sky Survey, which created the most detailed 3D map of the universe. When the project began, it asked civilians to complete much simpler tasks. All one had to do was classify the shape of the Galaxy. The second stage of the project called for a more precise description of each image. It asked civilians to describe the arms of spiral galaxies, the size of their center bulges, etc. The third stage drew imaged from the Hubble telescope as well as the SDSS. Recently, scientists have combined the images from the Hubble surveys and the SDSS to create the most detailed imaged possible.

 

This project now uses images from the Dark Energy Camera Legacy (DECal) Survey, in addition to using the Hubble and SDS surveys. These cameras are the most sensitive and widest cameras used in the process of collecting images for this project. Since these camera’s are so sensitive, they produce images that are much clearer and more defined than the SDSS or Hubble surveys ever did, as shown in the image below. Galaxy Zoo has begun using these images to get the most accurate results in their study. Dark Energy Camera’s are used to not only make the clearest images of the universe, but they also measure dark energy.  Dark matter, and dark energy, make up a large portion of our universe. The DECaL survey uses infrared technology to create a map of our universe. The Dark Energy Camera Legacy Survey’s main focus is to collect the brightest images of faraway galaxies that cannot be seen with the naked eye. This survey is creating a layout of the universe by combining images of the night sky at different points in Earth’s rotation. The DECaLS project got me thinking about dark energy, because another aspect of this ‘map’ DECaLS is creating, is measuring the amount of dark matter and energy the universe is made of. I, personally, find this quite amazing because dark energy is a mystery to astrophysicists. It makes up over half of the universe, and yet no one knows what it is or where it comes from!

Figure 2: On the left is an image from the SDSS survey, and on the right is an image from the DECal survey. Both images are of the same galaxy.

Through the Galaxy Zoo project, civilians are helping scientist further understand the universe around us. By using clarified images from the DECaL survey, the scientist behind Galaxy Zoo can get the most accurate classifications from civilian’s submissions.  The classifying galaxy ‘game’ is helping categorize images of certain types of galaxies, and also figure out where large amounts of dark energy are. The clearer the images are, the more precise the classifications are. So get out there and start classifying!

Image sources:

Figure 1: http://blog.galaxyzoo.org/2012/09/

Figure2: http://blog.galaxyzoo.org/2015/09/21/new-images-for-galaxy-zoo-part-1-decals/

New images for Galaxy Zoo! Part 1 – DECaLS

Dark Matter and our Expanding Universe

by Dejamia Wouldfolk

96 percent of the universe is made of mysteries. The type of matter that we’re used to- things composed of atoms- makes up only 4 percent of the universe. When scientists were measuring the mass of galaxies they found weight that was unaccounted for even after they’d weighed stars, planets and other spacely things. We call the unknown substance responsible for the extra weight ”dark matter.”

Scientists began to look at galactic clusters, knots of galaxies, hypothesizing that the mass that was unaccounted for was hot gas. They found vast clouds of superheated gas but not enough to make up for the missing mass. They knew there was something else there because the gravity of the galactic clusters alone wasn’t enough to keep the gas from escaping the galaxies.

Scientists aren’t really sure what dark matter is but, they know for sure what it’s not. Scientists know for sure that dark matter isn’t red, white or brown dwarf stars. It also isn’t cold or hot gas. Neutron stars and black holes? Not those either. The term “dark matter” is just a placeholder for now, like the unknown variable of an algebra equation, the “X” or “Y” of the universe.

Scientists estimated the amount of dark matter and atom-based matter in the universe and entered it into a computer which drew a map of dark matter’s location in the universe based on the information provided. In the simulation, dark matter is shown as weblike material woven in  with regular matter, it could be everywhere. Astronomers have worked to create a similar dark matter map based on direct observation of galaxies’ mass.

Based on the evidence, most astronomers agree that dark matter exists. But they have more questions than answers. The biggest question, dare we say one of the biggest in all of cosmology is: Is it an undiscovered type of matter, or is it ordinary matter that we have difficulty observing? There is a lot of difficulty in knowing what dark matter is. Some scientists even believe that dark matter doesn’t exist and that we could just be misinterpreting the laws of gravity.  Astronomy researcher Stacey McGaugh came up with an alternative theory of gravity.

“We infer dark matter to be there. We infer it from its gravitational effects,” said McGaugh in an interview with Vice. McGaugh thinks that gravity’s effects might be different at different places in the universe.

In addition to the mysteries of dark matter, there is also dark energy. Contrary to scientists’ expectations, the expansion of the universe isn’t slowing down due to gravity, it is actually accelerating due to some unexplained outward force. Like dark matter, the term dark energy is used as a placeholder to refer to something we’re unsure of. We call the force that’s accelerating the expansion of the universe dark energy

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96% of the universe is made up of things that we are still unsure of-73% dark energy and 23% dark matter. The rest is normal matter made up of atoms, such as stars, that we do understand. Credit: http://www.nasa.gov/vision/universe/starsgalaxies/Collision_Feature.html

The graph above shows the relationship between the time Earth was created and how the universe has expanded since then. Credit: http://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy/

In conclusion, maybe we don’t know what’s in our universe as well as we thought we did. There could be endless possibilities of what the universe holds. Most scientists agree with the statement that dark matter exists. Of course there are still some that doubt its existence and would even go as far as to question our perception of the laws of gravity. A rhetorical question that comes to mind is “You can’t see air but, does it not exist?” Whether you choose to believe in dark matter or not, there is still something thats fills the missing mass of the universe.

Welcome to the Universe

By Dumanisha Ward

From : http://en.wikipedia.org/wiki/Big_Bang

This diagram basically shows the birth of our Universe and how it has changed over 13.7 billion years. The Y-Axis shows the size and location of the visible Universe. The X-Axis represents time from the beginning of the Big Bang expansion to what our Universe looks like today. As You can see the Universe was much denser in its early eras.

 

 

I have yet to hear a story about how the Universe all began that I understood, and if you’re anything like me, you would like to know what put us humans on the map. In science and in life, it is difficult to prove and understand why things are the way they are when you weren’t there to witness them firsthand. To illustrate the origins of the Universe (as well as life, gravity, etcetera), scientists, astronomers and other diligent researchers have spent decades studying and testing hypotheses to come up with theories. Two commonly known theories are the Steady State Theory and The Big Bang Theory.

A model of cosmology, the science of the origins and development of the Universe, that gained some popularity in the 1950s and 60s is the Steady State Theory. The Steady State Theory basically asserted that the general character of the Universe is not changing over time but it is growing (See Diagram Below). For example, imagine that you have an infinitely big flat sink with no drain, and you turn the faucet on. The water spreads out uniformly over more and more of the surface of the sink (because you are always adding more and more water from the faucet). Now imagine that the Universe was that water. This is like the Steady State Theory. The water filling the sink looks the same everywhere no part would be denser than other parts because water doesn’t bunch up anywhere. Water covers the surface equally. At the same time, the Universe would still be expanding. The Steady State Theory predicts two main things about the Universe, that the Universe is expanding and that its density is always the same because it doesn’t change over time.

From: http://cosmictimes.gsfc.nasa.gov/online_edition/1955Cosmic/origin.html

The first figure shows what scientist believe happens with the Big Bang Theory and the second figure shows what scientists believe happens with the Steady State Theory. In the Big Bang as time pass the space between the points grow and become less and less dense. In the Steady State Theory the density of the Universe remains the same and looks the same as time passes. 

 

 

Another model of cosmology is the “Big Bang Theory”. The Big Bang Theory asserts that the Universe in its earlier eras was denser and much hotter than the Universe today. The visible Universe that we observe today was initially as small as a pore on the skin. As time passed the space between particles in the Universe grows and has been decreasing in density every since the beginning (See Diagram Above). It asserts that the fabric of space itself began expanding like the surface of an inflating balloon. For example, imagine that there are dots all over the surface of a balloon. As you start to fill the balloon with air the dots on the balloon become further and further apart from each other. The concentration of the dots is decreasing. Therefore the Big Bang Theory makes two main predictions, that the Universe is expanding and that the Universe actually evolves over time (The Universe was denser in the past now it is less dense).

Observatories looked further back into the Universe’s early eras and noticed contradictions to the Steady State theory. The Universe does not look the same at all times. Things looked denser. There were two main observational results over the past few decades that led astronomers to certainty that the Universe began with the Big Bang. First, they found out that the Universe is expanding and changing over time. Second, astronomers could actually observe the Cosmic Microwave Background Radiation.

The Cosmic Microwave Background Radiation, also known as the CMB, is a faint glow of light that fills the Universe. It is the residual heat of creation and the oldest light that we can see with the right equipment. The CMB is just more evidence that proves why the Big Bang Theory is the most logical, accepted theory of the origins of the Universe. It is the afterglow of the Big Bang explosion. Looking at the Universe in its beginning stages, picture it as a room that is filled with dust and has no open windows or openings of any kind. The dust would make the room dark and gloomy. Because there is no way for the dust to escape the room, the room will continue to be dark with a high density of dust. What would happen if you turn the lights on in the dusty room? The room packed with dust, even with the lights on, looks dark because the light cannot escape the dust and the dust cannot escape the room. Now imagine that we open the windows and dust begins to escape the room. Can the light escape the dust? Now that the room has opened up the dust has spread over more territory and the light can finally get through and reach our eyes. In this example, the dust is like all of the other atoms that the Big Bang created that were compacted and the light is like the CMB (See Diagram Below). The escape of the CMB requires for the Universe to have once been compacted and dense. What the Universe actually looks like agrees with the Big Bang Theory, which is why it is the favored model of cosmology.

From: http://universeadventure.org/big_bang/cmb-origins.htm

The orange, blue, and green dots represents protons and electrons. When all of the particles were close together and dense the light (yellow) bounced off all of the particles because the high density trapped the light. Over time, as the Universe began to expand and become less dense the protons and electrons formed atoms and became spread out enough so that the light had room to escape. 

 

Describing the Universe doesn’t have to be completely complicated. Right? But if you still find it difficult to understand the origins of the Universe, even after reading this post, then I encourage you to take timeout to plan a visit to the Adler Planetarium and check out our newest exhibit “The Universe: A walk through Space and Time”.