For decades, astrophysicists have theorized that the majority of matter in our Universe is made up of a mysterious invisible mass known as “Dark Matter” (DM). While scientists have not yet found any direct evidence of this invisible mass or confirmed what it looks like, there are several possible ways we could search for it soon. One theory is that Dark Matter particles could collide and annihilate each other to produce cosmic rays that proliferate throughout our galaxy – similar to how cosmic ray collisions with the interstellar medium (ISM) do.
This theory could be tested soon, thanks to research conducted using the A Large Ion Collider Experiment (ALICE), one of several detector experiments at CERN’s Large Hadron Collider (LHC). ALICE is optimized to study the results from collisions between nuclei that travel very close to the speed of light (ultra-relativistic velocities). According to new research by the ALICE Collaboration, dedicated instruments could detect anti-helium-3 nuclei (the anti-matter counterpart to He3) as they reach Earth’s atmosphere, thus providing evidence for DM.
Researchers from Ohio State University have come up with a novel method to detect dark matter, based on existing meteor-detecting technology. By using ground-based radar to search for ionization trails, similar to those produced by meteors as they streak through the air, they hope to use the Earth’s atmosphere as a super-sized particle detector. The results of experiments using this technique would help researchers to narrow down the range of possible characteristics of dark matter particles.
First light is an exciting time for astronomers and engineers who help bring new telescopes up to speed. One of the most recent and significant first light milestones recently occurred at the Subaru Telescope in Hawai’i. Though it has been in operation since 2005, the National Astronomical Observatory of Japan’s (NAOJ) main telescope recently received an upgrade that will allow it to simultaneously observe 2400 astronomical objects at once over a patch of sky the size of several moons.
In a recent study published in the Journal of High Energy Physics, two researchers from Brown University demonstrated how data from past missions to Jupiter can help scientists examine dark matter, one of the most mysterious phenomena in the universe. The reason past Jupiter missions were chosen is due to the extensive amount of data gathered about the largest planet in the solar system, most notably from the Galileo and Juno orbiters. The elusive nature and composition of dark matter continues to elude scientists, both figuratively and literally, because it does not emit any light. So why do scientists continue to study this mysterious—and completely invisible—phenomena?
Individual contributors have become less and less prominent in scientific fields as the discipline itself has matured. Some individuals still hold the public spotlight for their discoveries, such as Peter Higgs with the Higgs boson, which several other physicists also theorized around the same time he did. However, the actual data that eventually gave Dr. Higgs and François Englert their Nobel prize were collected by the Large Hadron Collider, arguably one of the largest technical projects that took thousands of scientists decades to design, build, and test.
In their pursuit of understanding cosmic evolution, scientists rely on a two-pronged approach. Using advanced instruments, astronomical surveys attempt to look farther and farther into space (and back in time) to study the earliest periods of the Universe. At the same time, scientists create simulations that attempt to model how the Universe has evolved based on our understanding of physics. When the two match, astrophysicists and cosmologists know they are on the right track!
In recent years, increasingly-detailed simulations have been made using increasingly sophisticated supercomputers, which have yielded increasingly accurate results. Recently, an international team of researchers led by the University of Helsinki conducted the most accurate simulations to date. Known as SIBELIUS-DARK, these simulations accurately predicted the evolution of our corner of the cosmos from the Big Bang to the present day.
Dark matter has long been a mystery to astronomers, in no small part because it is so hard to measure directly. Its influence is plain when looking at its gravitational effects on objects such as far away galaxies, but measuring that influence directly has proved much trickier. But now, a team of scientists thinks they have a way to measure the influence of dark matter directly – all it would require is a specialized probe that sits really far away from Earth for a while.
According to our current Cosmological models, the Universe began with a Big Bang roughly 13.8 billion years ago. During the earliest periods, the Universe was permeated by an opaque cloud of hot plasma, preventing atoms from forming. About 380,000 years later, the Universe began to cool and much of the energy generated by the Big Bang converted into light. This afterglow is now visible to astronomers as the Cosmic Microwave Background (CMB), first observed during the 1960s.
One peculiar characteristic about the CMB that attracted a lot of attention was the tiny fluctuations in temperature, which could provide information about the early Universe. In particular, there is a rather large spot in the CMB that is cooler than the surrounding afterglow, known as the CMB Cold Spot. After decades of studying the CMB’s temperature fluctuations, a team of scientists recently confirmed the existence of the largest cold spots in the CMB afterglow – the Eridanus Supervoid – might be the explanation for the CMB Cold Spot that astronomers have been looking for!
Do you have a few minutes to spare and a thirst for knowledge about one of the greater mysteries of the Universe? Then head on over to ArsTechnica and check out the new series they’re releasing titled Edge of Knowledge, starring none other than Dr. Paul Sutter. In what promises to be an enlightening journey, Dr. Sutter will guide viewers through an eight-episode miniseries that explores the mysteries of the cosmos, such as black holes, the future of climate change, the origins of life, and (for their premiere episode) Dark Matter!
As far as astrophysicists and cosmologists are concerned, Dark Matter is one of the most enduring, frustrating, and confusing mysteries ever! Then, one must wonder why scientists are working so tirelessly to track it down? The short answer is: the most widely accepted theories of the Universe don’t make sense without out. The long answer is… it’s both complicated and long! Luckily, Dr. Sutter manages to sum it all up in less than 15 minutes. As an accomplished physicist, he also explains why it is so important that we track Dark Matter down!