How It All Began: “To Infinity and Beyond”

Orion Nebula

From Nebulae to Stars to Galaxies and Beyond!

“TO INFINITY AND BEYOND”

Mysteries galaxies cover,

Restlessness stars show,

Beauty planets exhibit,

In the infinity and beyond!

From minuscule neutrinos to the expanding Universe, astronomy rules the Fabric of the Cosmos. But in my birthplace, the sky is hidden by a mask of light pollution and fossil fuel wastes. I often pondered what lay above those hazy clouds. After emigrating from Shenyang, I saw for the first time a sky clearer than water and stars brighter than Zeus’ bolt. Thus began my fascination with astronomy. And like the constellations of the zodiac that appear in certain months, I had occasional close encounters with astronomy. There was a lesson in a 6th grade outdoor education class and a telescope viewing session in Pasadena. I even took an astronomy course at the community college. All of these transient, astronomical sparks ultimately culminated in my unforgettable COSMOS experience. My high school barely covers astronomy, so I rely on my home telescope, where all I can see is the moon, Jupiter, and Saturn. But in a university setting, I discovered and utilized the infinite, incredible resources for research and learning.

As the sun sank beneath the golden horizon, I waited patiently for the TAs to finish calibrating the 24-inch telescope inside the UCI observatory dome. After Dr. Smecker-Hane explained how to use a sky map, I mastered the technique and shouted out constellations: “Orion! Big Dipper!” Inside the observatory dome, I ascended the creaky steel ladder and gazed into the telescope’s eyepiece, seeing one area concentrated with stars, the open cluster M11. Though light years away, M11 seemed so impossibly close that I could reach up and snatch its stars out of the sky, as though I was a scientist observing stars on an ebony Petri dish through a microscope. On the 8-inch telescope, Mars shone like ancient blood-stained battlefields, while Saturn’s ice rings revolved as magnificently as clockwork.

The professors enlightened me with intriguing astronomy stories, such as the irony of Einstein’s obstinacy. Though he rejected Friedmann’s theory of an expanding universe, Einstein’s cosmological constant, when reversed, actually supports the theory of Universe acceleration. The program’s CLEA1 exercises prepared me for group projects as I learned some of the math behind astronomy― calculating the mass of Jupiter using its moons’ orbits and “blinking” to determine asteroids’ velocities. In one CLEA simulation, I found not galaxies, but portraits of scientists floating in space instead! For my group research project, “Stellar Spectra,” we observed the night sky, recorded images of Arcturus and Vega, reduced them with Linux software, and designed a poster board decorated with colored dots depicting the stars of the H-R Diagram. We presented our “findings” to parents, students, and professors at a science fair convention. During this research process, I imagined myself as the modern Galileo voyaging through territory few had traversed.

COSMOS was the launch pad in expanding my astronomy blog, coincidentally named “The Cosmos.”I blog actively, and have discovered kindred spirits with minds eager to learn, inquire, and comment. Originating globally across six continents in countries like Germany and India, the feedback I receive increases my fascination. COSMOS confirmed my desire to study astronomy, conduct research, and become a part of the scientific community. Astronomy is the oldest science, yet each discovery raises more questions. In every astronomical encounter I travel on an unforgettable journey invoked by imagination.

1 CLEA is an acronym for Contemporary Lab Experiences in Astronomy.

~ Tianjia Liu, 2012 ~

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The 8 Planets – Part 3: Earth

NEXT STOP: EARTH!

Earth, our home planet

Imagine a blank sphere floating in the middle of space. Now picture the whole sphere flooded by blue oceans, rivers, and lakes. And seven continents, defined by low elevation green patches, high elevation brown areas, and deserts golden brown. Add white ice caps capping the North and South Poles. And white swirling clouds in the atmosphere. Then tilt the whole sphere 23.5 degrees. There. Our home planet, Earth!

Third planet from the Sun and the only planet to support life, Earth, or the Blue Planet, formed 4.54 billion years ago from accretion of the solar nebula and first hosted life approximately 1 billion years ago. Though technically not named after any Gods, the Greek god Gaea is mother of the earth. Home to millions of species, Earth has the “Goldilocks Phenomenon” since all conditions including climate and temperature support life. Earth is in the “life zone,” where water exists in all three phases: gas, liquid, and solid. Earth’s surface is 30% land and 70% water. Collectively, the biosphere and the abundance of minerals support life. Earth’s atmosphere, specifically the ozone layer, and magnetic field blocks high-energy electromagnetic radiation harmful for life. The axis of the Blue Marble, the largest terrestrial planet, tilts 23.5 degrees, causing the four annual seasons. The hemisphere tilting toward the Sun is in summer and the other is in winter. In fact, Earth’s orbit is nearly circular and Earth is actually closer to the Sun in winter than in summer. Earth’s tectonic activity, or the sliding of tectonic plates, causes volcanic activity and earthquakes that renew Earth’s surface. A viscous liquid mantle and a rigid crust surround a solid core. Earth orbits the Sun once every 365.25 days and rotates once every 24 hours. Earth has one moon, or natural satellite.

THE MOON

The Moon

Earth only has one moon, called the Moon. Reflecting sun light, this natural satellite orbits the Earth once every ~29 days, seen in different phases throughout every month: New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Third Quarter, Waning Crescent. Formed about 4.53 billion years ago, the Moon is an imperfect sphere bombarded by asteroids and comets during the Late Bombardment Period 3.8-4.1 billion years ago. In fact, the Near Side is much smoother than the Far Side (never observed from Earth), so one theory is that the Moon was actually two chunks of material that collided. However, the giant impact hypothesis indicates that a large object collided into Earth’s surface and while some mass fused with Earth, the rest formed the Moon. This theory explains why the Moon’s interior is similar to that of Earth. The Moon’s gravitational pull contributes the movement of ocean tides, stabilizes Earth’s tilt, and gradually slows the Earth’s rotation.

OVERVIEW

  • Order in Solar System: #3
  • Number of Moons: 1
  • Orbital Period: 1 year
  • Rotational Period: 1 day
  • Mass: 2.9736 x 10^24 kg
  • Volume: 1.08321 x 10^12 km³
  • Radius: 6,371 km
  • Surface Area: 5.10 x 10^8 km²
  • Density: 5.515 g/cm
  • Surface Pressure: 101.325 kPa
  • Eccentricity of Orbit: 0.0167
  • Surface Temperature (Average): 287.2 K
  • Escape Velocity: 11.186 km/s
  • Apparent Magnitude: N/A

COSMOS: UCI – Part 2

UCI Observatory

The UCI Observatory is located about a mile from the UCI campus. Though relatively small compared to famous observatories such as Keck Observatory in Hawaii or Kitt Peak Observatory in Arizona, the UCI Observatory serves basic viewing purposes. UCI Observatory dome houses a 24-inch telescope with a CCD camera and a 8-inch portable telescope. UCI professor Dr. Tammy Smecker-Hane and TAs Liuyi Pei, John Phillips, and Shea Garrison-Kimmel adjusted the telescopes and pointed them toward objects of interest, among which were the Ring Nebula, Mars, Saturn, star clusters, and a binary star system.

“As a bumpy, seat-wrangling dirt road emerges, a muddy, night-black SUV launches itself past ironclad gates. City lights twinkle to the left; hills lined with sharp grasses cast shadows to the right. Music blasts from speakers; Cosmonauts chatter nonstop, voices intermixed. A gray-white dome emerges and four shadows await, silently calibrating the 24 and 8-inch ocean-blue telescopes. As the sun dips beneath the horizon, night blankets the earth and icy air tackles my vest and slacks. First the moon, then Vega and Ursa Major— the true celestial sphere has appeared.” – Tianjia Liu

COSMOS: UCI – Part 1

COSMOS: UCI – Part 1

COSMOS Cluster 2 as Saturn and Its Moons

COSMOS Cluster 2 as Higgs Boson

This past month (June 24, 2012- July 21, 2012), I attended the COSMOS (California State Summer School for Mathematics and Science) at the University of California, Irvine, with brilliant minds from Northern and Southern California, as well as other states. The 152 students were divided into 8 clusters. I was part of Cluster 2: Astronomy and Astrophysics. With 22 other COSMOS students, I ventured into the world of astronomy and astrophysics unraveled by UCI professors Dr. Tammy Smecker- Hane, Dr. James Bullock, Dr. Aaron Barth, Dr. Erik Tollerund, TAs John Phillips, Liuyi Pei, and Shea Garrison-Kimmel, and Teacher Fellow Lisa Taylor. I discovered that all students shared a strong passion for astronomy and high aptitudes for learning. It has been my honor to learn with the students, listen to the professors’ lectures, and follow the TAs’ instructions for CLEA (Contemporary Laboratory Experiences in Astronomy) Labs.

For a cumulative final, the TAs divided the class into 8 groups for Project Labs:

“Deriving the Mass of Saturn” (By: Angel Guan, Francisco Terrones, and Luis Loza; Directed By: Liuyi Pei)

1. Deriving the Mass of Saturn

“Finding the Angular Velocity of an Asteroid” (By: Rachel Banuelos and Luis Salazar; Directed By: John Phillips)

2. Finding the Angular Velocity of Asteroids

3. Properties of an Eclipsing Binary Star System

  • By: Carlin Liao, Matthew Thibault, Sara Sampson; Directed By: Shea Garrison-Kimmel

4. Determining Stars’ Properties Using Stellar Spectra

  • By: Tina Liu, Noemi Urquiza, John Cabrera; Directed By: John Phillips

“Determining the Properties of Open Cluster M11” (By: Luzanne Batoon, Julian Rose, Janet Lee; Directed By: Tammy Smecker-Hane)

5. Determining the Properties of Open Cluster M11

“Determining the Properties of Globular Cluster M13” (By: Dennis Feng, Maricruz Moreno, Collen Murphy; Directed By: Tammy Smecker-Hane)

6. Determining Properties of Globular Cluster M13

7. Dark Matter in the Universe: Measuring the Rotation of Spiral Galaxies

  • By: Emma MacKie, Danny Tuthill, Michael Cox; Directed By: Shea Garrison-Kimmel)

8. Number Counts of Distant Galaxies and the Shape of the Universe

  • By: David Wong, Thomas Purdy, Joshua Heck; Directed By: Liuyi Pei

“Determining Stars’ Properties Using Stellar Spectra” (By: Tina Liu, Noemi Urquiza, John Cabrera)

 The red, white, yellow, and blue dots in the background represent stars of the H-R Diagram, including main sequence stars, red giants, and white dwarfs.

My Project: Determining the Properties of Stars Using Stellar Spectra (By: Tina Liu, John Cabrera, and Noemi Urquiza; Directed By: John Phillips)

ABSTRACT: Stellar spectra are fundamental in understanding properties — temperature, spectral type, chemical composition, and mass — of stars.  A spectrum is the amount of light that a star emits through narrow slit about 1 Angstrom in width. With the UCI Observatory’s 24-inch telescope and its photograph and ST-8 CCD camera, images of stars’ spectra — those of Arcturus, Vega (HD172167), and HD142780— were taken. Using the software program IRAF, the spectra were extracted, calibrated, and analyzed. Since stars are classified by spectral types, stellar spectra help distinguish a more massive and hotter star from a less massive and cooler star. Analyzing the strengths of absorption lines shows the stars’ compositions of elements such as hydrogen, helium, and calcium. While hotter stars such as Vega are more massive and have strong hydrogen absorption lines, cooler stars such as Arcturus are less massive and have strong neutral metals lines. Understanding stars’ properties leads to a better grasp of the past, present, and future of the Universe.

QUESTION: How can we use stellar spectra to determine the properties of stars such as spectral type, temperature, mass, and chemical composition?

Spectra of different elements including hydrogen, helium, and neon

BACKGROUND INFORMATION: Stars, actually infinitesimally small points of light, appear to twinkle because light refracts at Earth’s atmosphere. Held by gravity, stars shine due to nuclear fusion, its source of fuel. Their lifetimes depend primarily on mass; for their prime of life, stars, travel along the main sequence on the Hertzsprung- Russell, or Color- Magnitude Diagram. A stellar spectrum is the amount of light a star emits at a narrow wavelength interval (about 1 Angstrom, or 10^-10 meters). Each element has a distinguishable pattern of absorption lines (dark bands along the spectrum). Spectral types are a classification scheme developed by Annie Jump Cannon in the late 1800s and early 1900s. The spectral types are ordered in decreasing surface temperatures: O, B, A, F, G, K, M. Originally the classification scheme was A, B, C, D, etc. and stars were ordered according to the strengths of their Balmer (hydrogen) lines. Since stars with the strongest Balmer lines are not necessarily the hottest stars (hotter temperatures caused electrons to be excited and the atom to be ionized- lose electrons), the scheme was rearranged. The two stars analyzed were two variable stars: Arcturus of the constellation Boötes and Vega of the constellation Lyra.

MATERIALS:

  • 24-inch telescope, ST-8 CCD camera
  • Needed Files on Linux (software):
    • uciobs_fear_lowres.dat (from observatory website): List of arc lines used for wavelength calibration
    • arc_red.jpg (from website): Plots of arc images, with wavelengths of prominent lines
    • plotspec.pro : Plots the reduced spectrum and marks absorption lines that are found in LINES.UCI file
    • wave : File containing wave limits of reduced spectra. Needed to run plotspec.pro
    • LINES.UCI : Input file for plotspec.pro that contains prominent absorption lines to be marked on the final, reduced spectrum

PROCEDURES: Independent Variable: Wavelength (Angstroms); Dependent Variable: Intensity

  1. Take pictures of stars using a 24 inch telescope and ST-8 CCD camera
  2. Use DS9 on Linux to analyze and crop the portion of the image planned on using
  3. Edit parameters
  4. Label absorption lines according to reference, with each element specific to its wavelength
  5. Graph the spectrum
  6. Change “pixel” on the x-axis to “wavelength”
  7. Analyze the star’s properties by comparing them to predetermined spectral types.

RESULTS:

Arcturus Spectrum

Arcturus: “K” type star, 4,290 K, 1.5 solar masses, absence of hydrogen lines and abundance of neutral metal lines

Vega spectrum

Vega: “A” type star, 9,600 K, 2.14 solar masses, strong hydrogen lines

HD142780 spectrum

HD142780: “M” type star, 3,000 K, 0.2 solar masses, absence of hydrogen lines and abundance of neutral metal lines.

CONCLUSION: By analyzing the absorption lines on the stars’ spectra, we determined the spectral types of each, thus allowing us to find their respective properties. The absence of hydrogen lines and prevalence of neutral metals in Arcturus’ spectrum allowed us to identify it as a K type star (Figure 1) . Vega’s spectrum contained strong hydrogen and ionized metal lines. Therefore we classified it as an A type star (Figure 2). Because the spectrum revealed absent hydrogen lines and visible neutral metals, we classified it as a M type star (Figure 3).

DISCUSSION: WHY DO STELLAR SPECTRA MATTER FOR THE FUTURE OF ASTRONOMY?

  • Map galaxies
  • Map the Universe
  • Learn about the lifetimes of different stars
  • Use information on old stars to learn about conditions after the Big Bang
  • Learn about what has happened in the Universe since the Big Bang

REFERENCES:

Blumenthal, G., Burstein, D., Greeley, R., Hester, J., Smith, B., & Voss, H. G. (2007). Light, The Tools of the Astronomer, Taking the Measure of Stars. In 21st Century Astronomy. (2nd ed.). (pp. 92-128, 134-158, 380-385). New York, New York, U. S. A.: W. W. Norton & Company.

Kaler, J. B. (2010, July 30). Spectra. University of Illinois. Retrieved July 13, 2012, from http://stars.astro.illinois.edu/sow/spectra.html

Special Thanks to: COSMOS, UCI Professors and Graduate Students, our Teacher Fellow, and Cluster 2: Astronomy and Astrophysics!

COSMOS: UCI – Part 2