Exploring the Hidden Universe
Our Team ...
Moreom Akter (WIU Graduate Student)
E. D. Araya (WIU Professor)
This outreach activity:
Join with the WIU Physics Department faculty and students in hands-on and computer-based activities in the area of astronomy, within the topic of exploring the 'hidden' Universe. Students will learn about software that can be installed on their computers to explore the night sky, and how we can use physical principles and observations obtained at different wavelengths of the electromagnetic spectrum to reveal objects that cannot be studied with visible light. The activity is intended for K-12 students.
Before we begin:
Using Zoom:
Let's test the Chat:
Let's have fun answering a question, send a private chat to Dr. Araya with your answer (just type A, B, C, D, or ?).
Which is the nearest star to Earth?
A) Sirius
B) Proxima Centauri
C) Polaris
D) None of the above
? ) No idea!
Let's download a program we will be discussing later today
We will be discussing a video game in the last part of today's astronomy activities, but to save time, let's start the download process.
Then, you will then be able to select the version of the game for your computer and start the download process (it may take several minutes). We will install it and run it later today.
Here the link to download the program:
Introduction: Group Discussion
Sometimes you may hear someone saying: "You have to see it to believe it". Do you think that in science we need to see things to believe they exist?
Let's see what the group thinks about this:
Which of the following options best match your opinion about this question:
A) Yes! Scientists must see things to believe they exist.
B) No! Scientist can believe in theories without any evidence.
C) Science can reveal the existence of different natural phenomena that cannot be directly observed with our eyes.
D) I disagree with all the options above!
?) Not really sure!
Activity 1: Stellarium - Seeing the Future, Seeing through the Light
Stellarium is a free program that can be used on the internet or downloaded. The program allows the user to observe the night sky at various locations, times, and dates. A user can look at a specific object of interest by searching it or observe just how it currently is.
Seeing though the light:
A1, Question 1: Is the planet Saturn above the horizon right now in Macomb, Illinois?
A) Yes
B) No
? ) Not sure (technical problems or not enough time to complete the activity)
Revealing the Future:
A1, Question 2: Will the Moon be visible 10 pm (22 hours) tonight in Macomb, Illinois?
A) Yes, it will be a crescent moon.
B) Yes, it will be a quarter moon.
C) Yes, but it will be a gibbous moon (in between a quarter moon and a full moon).
D) Yes, it will be a full moon.
E) No, the Moon will be below the horizon at 10 pm tonight.
? ) Not sure (technical problems or not enough time to complete the activity).
Activity 2: Seeing the Hidden Nature of Light:
Polarization and Magnetic Fields
Exploring Polarization of Light with Linear Polarized Filters and Light Pen
Step 1: Shine the light through one polarized filter toward the surface of your desk as shown in the figure:
A2, Question 1:
When the light passes through the polarized filter, the light projected onto the surface of your table is __________________ the projected light without the filter.
A) brighter than
B) dimmer than
C) same as
? ) Not sure
Step 2: Add another filter, and repeat the experiment:
A2, Question 2:
When the light passes through TWO aligned polarized filters, the light projected onto the surface of your table is __________________ as when the light passed only through one filter.
A) brighter
B) a lot dimmer
C) a bit dimmer
? ) Not sure
Step 3: Repeat the experiment, but with one of the filters rotated 90deg with respect to the other as shown in the picture:
A2, Question 3:
When the light passes through two polarized filters rotated 90deg with respect to each other, the light projected onto the surface of your table __________________ .
A) is a bit brighter than when the two filters were aligned.
B) is a bit dimmer than when the two filters were aligned.
C) is the same as when the two filters were aligned.
D) almost completely disappeared.
? ) Not sure
One Filter
Two Aligned Filters
Two Filters rotated 90 degrees
How can we explain the experiment?
Following figures and additional explanation about polarization can be found in Physics LibreText (click on the icon):
Light is an electromagnetic wave.
The polarized filters act as slits, that allow one direction of oscillation to propagate but not the other.
Unpolarized light has waves oscillating in all directions, only those aligned with the filter can pass.
The first filter allows only one polarization direction to propagate, once selected, the light can pass through the second filter.
If the two filters are rotated 90 degrees with respect to each other, then no light can pass.
Polarized light can reveal large scale magnetic fields
Telescopes like SOFIA can detect polarized light and show hidden magnetic fields.
Stars form in large filaments of dust and gas, magnetic fields are parallel to the filament where few stars are forming, and perpendicular where lots of stars are forming.
This seems to be one way how nature regulates star formation.
NASA / SOFIA / T. Pillai / J. Kauffmann; Spitzer/IRAC, NASA / JPL-Caltech / L. Allen
Galaxy M51, HST image (NASA, ESA)
Galaxy M51, HST image (NASA, ESA) + magnetic field lines (SOFIA, NASA)
See additional information here.
(a) Surface of water in a lake as seen without a polarized filter. (b) Surface of water as seen with a polarized filter.
Explore polarization, look at the reflected light from shiny surfaces such as the floor or a swimming pool, from TVs, laptops, the sky (but DO NOT look at the Sun), etc.
Visit Physics LibreText to learn more:
Activity 3: Revealing the Hidden Nature of Galaxies
Galaxy M51, HST image (NASA, ESA)
Galaxy Her A, HST image (NASA, ESA)
Very Large Array Telescope
New Mexico
NRAO/NSF
Sometimes, the relation between the radio emission and the host galaxy is not clear, we will contribute to a citizen science project to find the radio emission associated with galaxies from a LOFAR radio survey:
LOFAR Radio Observatory in Europe
Zooniverse: citizen science
Radio Galaxy Zoo: LOFAR
Radio Image
Solid Ellipse: main radio source in the field.
Dashed Ellipses: other radio sources that may or may not be associated with the main radio source.
Optical Image
Ellipses show the location of the radio sources
Optical Image: Picture
Radio Image: Yellow Contours
GOAL 1: Help identify whether the radio sources marked with dashed ellipses are likely related to the radio source marked with the solid ellipse.
GOAL 2: Help identify the host galaxy.
GOAL 3: Identify problems with the images.
A3, Question 1: Which dashed ellipse should we mark, if any?
A3, Question 2: Which is the likely host galaxy?
Time for you to participate in the scientific process, classify a couple of images, then you can register and sign-in to record your contributions to this citizen-science project, click on the link:
Activity 4: Revealing the Hidden Chemical Composition of Astronomical Objects
Diffraction Grating and Light Pen
Continuum Spectrum:
all the colors of the rainbow
Demo about Spectral Lines using a Diffraction Grating
Let's use At Play in the Cosmos to explore how light can be used to reveal chemical composition of astronomical objects. With this game, you will also be able to explore many other astronomy concepts.
Intro Screen
Starship to use
Different scientific missions
Chemical composition of Mars' atmosphere.
