Universe Today

May 17, 2023May 12, 2023 by Paul M. Sutter

Astronomers Prepare for the Next Thousand Years of Hazardous Asteroid Impacts

This diagram shows the orbits of 2,200 potentially hazardous objects as calculated by JPL’s Center for Near Earth Object Studies (CNEOS). Highlighted is the orbit of the double asteroid Didymos, the target of NASA’s Double Asteroid Redirect Test (DART) mission. Credit: NASA/JPL-Caltech

It is as inevitable as the rising of the Sun and the turning of the tides. Someday another large rock from space will crash into the Earth. It has happened for billions of years in the past and will continue to happen for billions of years into the future. So far humanity has been lucky, as we have not had to face such a catastrophic threat. But if we are to survive on this planet for the long term, we will have to come to terms with the reality of hazardous asteroids and prepare ourselves.

May 17, 2023May 17, 2023 by Matt Williams

Life Probably Didn't Have a Hand in Creating Organic Deposits on the Surface of Mars

ExoMars Trace Gas Orbiter analyses the martian atmosphere. Credit: ESA/ATG medialab

At this very moment, eleven robotic missions are exploring Mars, a combination of orbiters, landers, rovers, and one aerial vehicle (the Ingenuity helicopter). Like their predecessors, these missions are studying Mars’ atmosphere, surface, and subsurface to learn more about its past and evolution, including how it went from a once warmer and wetter environment to the freezing, dusty, and extremely dry planet we see today. In addition, these missions are looking for evidence of past life on Mars and perhaps learning if and where it might still exist today.

One particularly interesting issue is how the atmosphere of Mars – primarily composed of carbon dioxide (CO₂) – is relatively enriched with Carbon-13 (¹³C), aka. “heavy carbon.” For years, scientists have speculated that the ratio of this isotope to “light carbon” (¹²C) might be responsible for organics found on the surface (a sign of biological processes!). But after analyzing data from the ESA’s ExoMars Trace Gas Orbiter (TGO) mission, an international team led by The Open University determined that these organics may be “abiotic” in origin (i.e., not biological).

May 17, 2023May 17, 2023 by Nancy Atkinson

Kathy Lueders Was NASA's Top Human Spaceflight Official. Now She Works for SpaceX

Kathy Lueders, seen in the Launch Control Center at NASA’s Kennedy Space Center applauds during the SpaceX Demo-2 mission in May 2020, the first launch with astronauts on board the SpaceX Crew Dragon. At the time, Lueders the manager of NASA's Commercial Crew Program; she has now joined SpaceX. Credit: NASA

Another of NASA’s top human spaceflight officials has joined SpaceX. Kathy Leuders, the former associate administrator for NASA’s Space Operations Mission Directorate, retired from NASA on May 1 after 31 years of service. But this week, CNBC reports that Lueders has joined SpaceX at the company’s Starbase facility in Texas. She follows Bill Gerstenmaier, who retired from NASA in 2020 and became a senior executive at SpaceX as build and flight reliability vice president.

May 17, 2023May 17, 2023 by Brian Koberlein

Astronomers Have a New Way to Measure the Expansion of the Universe

Multiple observations of the Refsdal supernova. Credit: Kelly,et al

The cosmos is expanding at an ever-increasing rate. This cosmic acceleration is caused by dark energy, and it is a central aspect of the evolution of our universe. The rate of cosmic expansion can be expressed by a cosmological constant, commonly known as the Hubble constant, or Hubble parameter. But while astronomers generally agree this Hubble parameter exists, there is some disagreement as to its value.

May 17, 2023May 17, 2023 by Andy Tomaswick

An Innovative Heat Shield That Doesn’t Need to Be Replaced Between Missions

A revolution in space manufacturing is coming. Enabled by cheaper launch costs, companies are scrambling to take advantage of easier access to the benefits space offers as a manufacturing environment. These include a constant vacuum, near absolute zero temperatures, and a lack of any significant gravity. These features would enable easier processing and manufacturing of hundreds of products, from pharmaceuticals to metal alloys. The tricky part is getting them back down to Earth, where they can be used.

A company based in the UK recently revealed what they think is a viable solution for that. Space Forge, which is developing a reusable manufacturing platform for use in space, recently discussed their Pridwen heat shield. The most remarkable thing about this new heat shield is it’s reusable.

May 16, 2023May 16, 2023 by Alan Boyle

Astronomers Want Your Help to Identify Risky Asteroids

The Catalina Sky Survey 60-inch telescope observes the cosmos from Mount Lemmon in Arizona. (Credit: Catalina Sky Survey)

You, too, can be an asteroid hunter — thanks to a citizen-science project launched by the University of Arizona’s Lunar and Planetary Laboratory. And you might even get a scientific citation.

The project is enlisting human spotters to verify potential detections of space rocks moving through the field of view of the Catalina Sky Survey’s telescopes. The NASA-funded survey is charged with keeping track of more than a million asteroids, with a principal goal of identifying near-Earth objects that could pose a risk to our planet.

More than 14,400 near-Earth objects, or NEOs, have been discovered by the Catalina Sky Survey during the past 30 years, including 1,200 that were identified just in the past year. That adds up to nearly half of the known NEO population.

The problem is, astronomers know there are still lots of unknown asteroids out there — too many for them to spot without an assist from amateurs. “We take so many images of the sky each night that we cannot possibly look through all of our potential real asteroids,” Carson Fuls, a science engineering specialist for the Catalina Sky Survey, said in a NASA news release. That’s where the Daily Minor Planet can make a difference.

May 16, 2023May 17, 2023 by Laurence Tognetti

It’s Time to Figure Out How to Land Large Spacecraft Safely on Other Worlds

Exhaust plume-surface interaction, more commonly known as brownout, while landing on the Moon. (Credit: Reproduced with permission from A. Rahimi, O. Ejtehadi, K.H. Lee, R.S. Myong, Acta Astronautica, 175 (2020) 308-326. ©2018 Elsevier.)

One of the most iconic events in history is Apollo 11 landing on the lunar surface. During the descent, astronauts Neil Armstrong and Edwin “Buzz” Aldrin are heard relaying commands and data back and forth to mission control across 385,000 kilometers (240,000 miles) of outer space as the lunar module “Eagle” slowly inched its way into the history books.

In the final moments before touchdown, Aldrin can be heard saying, “Picking up some dust”, followed by large dust clouds shooting outward from underneath from the spacecraft as the exhaust plumes interacted with the lunar surface, more commonly known as brownout or brownout effect. This significantly reduced the visibility for Armstrong and Aldrin as they landed, and while they successfully touched down on the Moon, future astronauts might not be so lucky.

May 16, 2023May 16, 2023 by Carolyn Collins Petersen

Seismic Waves Help Map the Core of Mars for the First Time

An artist’s depiction of the Martian interior and the paths taken by the seismic waves as they traveled through the planet’s core. Image courtesy of NASA/JPL and Nicholas Schmerr.

More than a hundred years after geologists first observed how seismic waves traveled through Earth, they’ve achieved another seismic first. This time, they measured “core-transiting seismic waves” moving through Mars. The InSight lander’s seismic instrument tracked shockwaves generated by an earthquake and an impact event. Their behavior revealed for the first time that Mars very likely has a liquid core. It’s made of a single blob of molten iron alloy.

May 16, 2023May 17, 2023 by Matt Williams

The Moon has a Solid Core Like the Earth

A new study suggests that the moon's magnetic field from a dynamo in its liquid metallic core (inner red sphere) lasted 1 billion years longer than thought. (Image credit: Hernán Cañellas (provided by Benjamin Weiss))

Some fifty years ago, the Apollo Program sent the first astronauts to the Moon. In addition to the many science experiments they conducted on the surface, the Apollo astronauts brought back samples of lunar rock for analysis. The Soviet Luna program sent several robotic missions to the Moon around the same time that conducted sample-return missions. The examination of these rocks revealed a great deal about the composition of the Moon and led to new theories about the formation and evolution of the Earth-Moon system.

For example, analysis of the rocks revealed that the Earth and the Moon are similarly composed of silicate minerals and metals. This led to theories that the Moon’s interior is similarly divided into a silicate mantle and crust and a metallic core. However, many aspects of this theory, like the structure of the core (solid or molten?), have been debated for decades. According to new findings by a team of French scientists, it is now a scientific certainty that the Moon’s innermost region consists of a solid inner core surrounded by a molten outer core (just like Earth’s).

May 16, 2023May 12, 2023 by Paul M. Sutter

Astronomers Find a “Red Nova”: A Main-Sequence Star Just Eating its Planet

Artist's impression of a Jupiter-sized exoplanet orbiting an M-dwarf star

Back in 2020 astronomers observed a Red Nova, which while enormously powerful, is on the low side of energetic events in the universe. Now an astronomer has studied the event in close detail and has come to the conclusion that we have just witnessed a star destroying its own planet.