Cool Astronomical Discoveries
New studies measure all the light stars ever emitted in the history of the universe, find the Milky Way in the process of ingesting a miniature galaxy, demonstrate evidence of an asteroid-induced global firestorm, and detect supernova remains in fossils. All of these discoveries are “too cool” to not share.
Considering all the challenging problems scientists study, results sometimes come through unusual means, often uncovering unexpected scenarios. The following provides a sampling of these cool discoveries.
Measuring All the Starlight since the Beginning
Starting somewhere between 200 and 700 million years after the big bang and continuing through today, stars have illuminated the universe. A photon emitted from a star travels through space until it hits something else like a gas cloud, another star, or even another photon. Because most of the universe contains very little “stuff,” photons from all stars formed over the last 13+ billion years still flow through the universe. Astronomers would like to measure the quantity of these photons; however, the light from stars in our galaxy outshines this background starlight.
Astronomers solved this challenge by making observations in a different part of the electromagnetic spectrum—gamma rays. As gamma rays traverse the starlight background, they interact with the starlight and form electron/positron pairs. As astronomers observe distant gamma-ray sources (like a blazar), they see the gamma-ray intensity diminish with increasing distance. Researchers found this signature using data from the Fermi satellite and it allowed them to determine the total amount of starlight emitted since the beginning of the universe!1
A Light Snack for the Milky Way Galaxy
Our solar system resides in one of the two large galaxies that dominate a relatively small galaxy cluster. As astronomers measure the environment around the Milky Way Galaxy (MWG) (the other large galaxy is Andromeda), they find streams of stars, remnants of ancient star clusters and small galaxies, strewn about the outskirts. The MWG tore apart these clusters and galaxies and is now consuming their stars and gas. Observations from the Sloan Digital Sky Survey (SDSS) revealed a swath of stars, dubbed the Triangulum stream, in the southern half of the galactic sky. Researchers conclude that the Triangulum stream resulted from the MWG eating a globular cluster. They expect detailed measurements of this stream and others will lead to a better understanding of the MWG’s gravitational potential.2
Global Firestorm from Dinosaur-Killing Asteroid Impact
Some uncertainty still surrounds the exact cause of dinosaur extinction 66 million years ago. Large volcanic eruptions certainly contributed, as did a massive asteroid impact in the Yucatan Peninsula. New research adds to our understanding of the devastation the impact caused. When the asteroid (roughly 6 miles in diameter) collided with Earth, it vaporized a sizeable fraction of rock and ejected it high above the planet’s atmosphere. As this material fell back to Earth, it would have heated the upper atmosphere to temperatures well above 2,500oF for multiple hours! One scientist involved in the research likened such an environment to “a 1 megaton bomb exploding every four miles over the entire Earth.”
Such a global firestorm should have left extensive charcoal deposits, but past research found no corresponding evidence. Now a new study that corrects for changing sedimentation rates shows that the amount of charcoal from that era matches expectations based on the firestorm scenario.3 One can understand why the dinosaurs and more than 80 percent of all life died 66 million years ago.
Ancient Bacteria Record Supernova Explosion
When large stars exhaust their fuel, they die in a powerful supernova explosion that scatters stellar remains throughout space. Studies of the abundance of elements in the solar system and on Earth indicate that the solar system formed in the vicinity of at least two different supernovae (and possibly more). Iron-60, a product solely of supernovae, decays with a half-life of 2.62 million years. Thus, any iron-60 discovered on Earth indicates the presence of a recent supernova event. Studies by German scientists found traces of iron-60 in microfossils of magnetotactic (organisms that orient along the Earth’s magnetic field) bacteria living over 2 million years ago.4
Each of these discoveries demonstrates that we live in an amazing universe—one designed by a creative and an intelligent God.
1. A. Domínguez et al., “Detection of the Cosmic γ-ray Horizon from Multiwavelength Observations of Blazars,” Astrophysical Journal 770 (June 10, 2013): 77.
2. Ana Bonaca, Marla Geha, and Nitya Kallivayalil, “A Cold Milky Way Stellar Stream in the Direction of Triangulum,” Astrophysical Journal Letters 760 (November 20, 2012): L6.
3. Douglas S. Robertson et al., “K-Pg Extinction: Reevaluation of the Heat-Fire Hypothesis,” Journal of Geophysical Research: Biogeosciences 118 (March 2013): 329–36.
4. Technische Universitaet Muenchen, “First Biological Evidence of a Supernova,” ScienceDaily, posted May 8, 2013, http://www.sciencedaily.com /releases/2013/05/130508123022.htm.