Featured Archives

February 8, 2023February 8, 2023 by Matt Williams

Could a Dark Energy Phase Change Relieve the Hubble Tension?

This illustration shows three steps astronomers used to measure the universe's expansion rate (Hubble constant) to an unprecedented accuracy, reducing the total uncertainty to 2.3 percent. The measurements streamline and strengthen the construction of the cosmic distance ladder, which is used to measure accurate distances to galaxies near to and far from Earth. The latest Hubble study extends the number of Cepheid variable stars analyzed to distances of up to 10 times farther across our galaxy than previous Hubble results. Credits: NASA, ESA, A. Feild (STScI), and A. Riess (STScI/JHU)

According to the most widely-accepted cosmological theories, the Universe began roughly 13.8 billion years ago in a massive explosion known as the Big Bang. Ever since then, the Universe has been in a constant state of expansion, what astrophysicists know as the Hubble Constant. For decades, astronomers have attempted to measure the rate of expansion, which has traditionally been done in two ways. One consists of measuring expansion locally using variable stars and supernovae, while the other involves cosmological models and redshift measurements of the Cosmic Microwave Background (CMB).

Unfortunately, these two methods have produced different values over the past decade, giving rise to what is known as the Hubble Tension. To resolve this discrepancy, astronomers believe that some additional force (like “Early Dark Energy“) may have been present during the early Universe that we haven’t accounted for yet. According to a team of particle physicists, the Hubble Tension could be resolved by a “New Early Dark Energy” (NEDE) in the early Universe. This energy, they argue, would have experienced a phase transition as the Universe began to expand, then disappeared.

February 7, 2023February 8, 2023 by Matt Williams

The World's Largest Radio Telescope Just Scanned 33 Exoplanets for a Signal From Aliens

The Five-hundred-metre Aperture Spherical Telescope (FAST) has just finished construction in the southwestern province of Guizhou. Credit: FAST

The Five-hundred-meter Aperture Spherical Telescope (FAST), located in China, is currently the world’s largest and most sophisticated radio observatory. While its primary purpose is to conduct large-scale neutral hydrogen surveys (the most common element in the Universe), study pulsars, and detect Fast Radio Bursts (FRBs), scientists have planned to use the array in the Search for Extraterrestrial Intelligence (SETI). Integral to this field of study is the search for technosignatures, signs of technological activity that indicate the presence of an advanced civilization.

While many potential technosignatures have been proposed since the first surveys began in the 1960s, radio transmissions are still considered the most likely and remain the most studied. In a recent survey, an international team of SETI researchers conducted a targeted search of 33 exoplanet systems using a new method they call the “MBCM blind search mode.” While the team detected two “special signals” using this mode, they dismissed the idea that they were transmissions from an advanced species. Nevertheless, their survey demonstrated the effectiveness of this new blind mode and could lead to plausible candidate signals in the future.

February 7, 2023February 7, 2023 by David Dickinson

Check Out This Great View of Comet 96P Machholz, Courtesy of SOHO

Now’s the time to catch periodic Comet 96P Machholz on its encore dawn performance, before it slides out of view.

So, have you been following the touted ‘green comet,’ E3 ZTF? To be sure, it’s nothing more than a fuzzy patch, a binocular comet sliding through the constellation Auriga looking like a globular cluster that refuses to resolve into focus. Though E3 ZTF may not live up to the hype, it does have one thing going for it: it is currently well-placed for northern hemisphere viewers. It also put on a great show for astrophotographers as it recently completed an orbital plane-crossing, as seen from our Earthly vantage point.

February 3, 2023February 3, 2023 by Matt Williams

Mars Ingenuity Kicks up a Surprising Amount of Dust Every Time it Lands

NASA's Mars Helicopters: Present, Future, and Proposed: A family portrait of Mars helicopters - Ingenuity, Sample Recovery Helicopter, and a future Mars Science Helicopter concept. Credits: NASA/JPL-Caltech.

There’s no way to sugarcoat it: Mars has a “dust problem.” The surface of the Red Planet is covered in particulate matter consisting of tiny bits of silica and oxidized minerals. During a Martian summer in the southern hemisphere, the planet experiences dust storms that can grow to encompass the entire planet. At other times of the year, dust devils and dusty skies are a persistent problem. This hazard has claimed robotic explorers that rely on solar panels to charge their batteries, like NASA’s Opportunity rover and the InSight lander, which ended their missions in 2018 and 2022, respectively.

Martian dust has also been a persistent challenge for the Ingenuity helicopter, the rotorcraft that has been exploring Mars alongside NASA’s Perseverance rover since February 2021. Luckily, the way it has kicked up dust has provided vital data that could prove invaluable for rotorcraft sent to explore other extraterrestrial environments in the future. Using this data, a team of researchers (with support from NASA) has completed the first real-world study of Martian dust dynamics, which will support missions to Mars and Titan (Saturn’s largest moon) in this and the next decade.

February 1, 2023February 1, 2023 by Matt Williams

Rolls-Royce Reveals a Nuclear Reactor That Could Provide Power on the Moon

For space agencies and the commercial space industry, the priorities of the next two decades are clear. First, astronauts will be sent to the Moon for the first time since the Apollo Era, followed by the creation of permanent infrastructure that will allow them to say there for extended periods. Then, the first crewed missions will be sent to Mars, with follow-up missions every 26 months, culminating in the creation of surface habitats (and maybe a permanent base). To meet these objectives, space agencies are investigating next-generation propulsion, power, and life support systems.

This includes solar-electric propulsion (SEP), where solar energy is used to power extremely fuel-efficient Hall-Effect thrusters. Similarly, they are looking into nuclear thermal propulsion (NTP) and compact nuclear reactors, allowing for shorter transit times and providing a steady power supply for Lunar and Martian habitats. Beyond NASA, the UK Space Agency (UKSA) has partnered with Rolls-Royce to develop nuclear systems for space exploration. In a recent tweet, the international auto and aerospace giant provided a teaser of what their “micro-reactor” will look like.

January 30, 2023January 30, 2023 by Matt Williams

Astronomers are Working on a 3D map of Cosmic Dawn

The HERA radio telescope consists of 350 dishes pointed upward to detect 21-centimeter emissions from the early Universe. Credit: HERA Partnership

The frontiers of astronomy are being pushed regularly these days thanks to next-generation telescopes and scientific collaborations. Even so, astronomers are still waiting to peel back the veil of the cosmic “Dark Ages,” which lasted from roughly 370,000 to 1 billion years after the Big Bang, where the Universe was shrouded with light-obscuring neutral hydrogen. The first stars and galaxies formed during this same period (ca. 100 to 500 million years), slowly dispelling the “darkness.” This period is known as the Epoch of Reionization, or as many astronomers call it: Cosmic Dawn.

By probing this period with advanced radio telescopes, astronomers will gain valuable insights into how the first galaxies formed and evolved. This is the purpose of the Hydrogen Epoch of Reionization Array (HERA), a radio telescope dedicated to observing the large-scale structure of the cosmos during and before the Epoch of Reionization located in the Karoo desert in South Africa. In a recent paper, the HERA Collaboration reports how it doubled the array’s sensitivity and how their observations will lead to the first 3D map of Cosmic Dawn.

January 30, 2023January 30, 2023 by Matt Williams

Future Space Telescopes Could be 100 Meters Across, Constructed in Space, and Then Bent Into a Precise Shape

Graphic depiction of Bend-Forming of Large Electrostatically Actuated Space Structures. Credit: Zachary Cordero

It is an exciting time for astronomers and cosmologists. Since the James Webb Space Telescope (JWST), astronomers have been treated to the most vivid and detailed images of the Universe ever taken. Webb‘s powerful infrared imagers, spectrometers, and coronographs will allow for even more in the near future, including everything from surveys of the early Universe to direct imaging studies of exoplanets. Moreover, several next-generation telescopes will become operational in the coming years with 30-meter (~98.5 feet) primary mirrors, adaptive optics, spectrometers, and coronographs.

Even with these impressive instruments, astronomers and cosmologists look forward to an era when even more sophisticated and powerful telescopes are available. For example, Zachary Cordero
of the Massachusetts Institute of Technology (MIT) recently proposed a telescope with a 100-meter (328-foot) primary mirror that would be autonomously constructed in space and bent into shape by electrostatic actuators. His proposal was one of several concepts selected this year by the NASA Innovative Advanced Concepts (NIAC) program for Phase I development.

January 29, 2023January 29, 2023 by Matt Williams

Astronomers Find 25 Fast Radio Bursts That Repeat on a Regular Basis

CHIME consists of four metal "half-pipes", each one 100 meters long. Image Credit: CHIME/Andre Renard, Dunlap Institute.

Like Gravitational Waves (GWs) and Gamma-Ray Bursts (GRBs), Fast Radio Bursts (FRBs) are one of the most powerful and mysterious astronomical phenomena today. These transient events consist of bursts that put out more energy in a millisecond than the Sun does in three days. While most bursts last mere milliseconds, there have been rare cases where FRBs were found repeating. While astronomers are still unsure what causes them and opinions vary, dedicated observatories and international collaborations have dramatically increased the number of events available for study.

A leading observatory is the Canadian Hydrogen Intensity Mapping Experiment (CHIME), a next-generation radio telescope located at the Dominion Radio Astrophysical Observatory (DRAO) in British Columbia, Canada. Thanks to its large field of view and broad frequency coverage, this telescope is an indispensable tool for detecting FRBs (more than 1000 sources to date!) Using a new type of algorithm, the CHIME/FRB Collaboration found evidence of 25 new repeating FRBs in CHIME data that were detected between 2019 and 2021.

January 27, 2023February 7, 2023 by Matt Williams

NASA and DARPA Will be Testing a Nuclear Rocket in Space

Artist concept of Demonstration for Rocket to Agile Cislunar Operations (DRACO) spacecraft, Credits: DARPA

The coming decades of space exploration will see astronauts return to the Moon, the first crewed missions to Mars, and robotic missions to the outer Solar System (among other things). These missions will leverage innovative technologies that allow faster transits, long-duration stays, and sustainable living far from Earth. To this end, NASA and other space agencies are investigating nuclear applications, especially where energy and propulsion are concerned. Many of these proposals have been on the books since the early space age and have been thoroughly validated.

On Tuesday, January 24th, NASA and the Defense Advanced Research Projects Agency (DARPA) announced they were launching an interagency agreement to develop a nuclear-thermal propulsion (NTP) concept. The proposed nuclear rocket is known as the Demonstration Rocket for Agile Cislunar Operations (DRACO), which would enable fast-transit missions to Mars (weeks instead of months). This three-phase program will culminate with a demonstration of the DRACO in orbit, which is expected to occur by early 2027.

January 25, 2023January 25, 2023 by Matt Williams

Study Shows How Cells Could Help Artemis Astronauts Exercise

NASA’s Orion spacecraft will carry astronauts further into space than ever before using a module based on Europe’s Automated Transfer Vehicles (ATV). Credit: NASA

In 2033, NASA and China plan to send the first crewed missions to Mars. These missions will launch every two years when Earth and Mars are at the closest points in their orbits (Mars Opposition). It will take these missions six to nine months to reach the Red Planet using conventional technology. This means that astronauts could spend up to a year and a half in microgravity, followed by months of surface operations in Martian gravity (roughly 40% of Earth gravity). This could have drastic consequences for astronaut health, including muscle atrophy, bone density loss, and psychological effects.

Aboard the International Space Station (ISS), astronauts maintain a strict exercise regimen to mitigate these effects. However, astronauts will not have the same option while in transit to Mars since their vehicles (the Orion spacecraft) have significantly less volume. To address this challenge, Professor Marni Boppart and her colleagues at the Beckman Institute for Advanced Science and Technology are developing a process using regenerative cells. This work could help ensure that astronauts arrive at Mars healthy, hearty, and ready to explore!