Astronomy

The forecasts predicted an extreme storm season in the Atlantic, but so far there have only been three named hurricanes – so where are all the storms?

The forecasts predicted an extreme storm season in the Atlantic, but so far there have only been three named hurricanes – so where are all the storms?

The two new Galileo satellites launched in April have entered service, completing the second of three constellation planes. With every addition to the constellation, the precision, availability and robustness of the Galileo signal is improved. The next launch is planned in the coming weeks and the remaining six Galileo First Generation satellites will join the constellation in the next years.

Although officially known as the celestial archer, the zodiacal constellation of Sagittarius is far better recognized as a teapot. Here's how to see it this season.

Construction of the world’s largest wind tunnel and its original 40- by 80-foot test section. A later expansion created an additional 80- by 120-foot test section. A Navy blimp, which would have been based at Hangars 2 and 3 at Moffett Field, patrols in the background.

A new video from an astronaut's vantage point in space captures a bright green burst over Earth as a meteor exploded in the night sky.

The ESA/JAXA BepiColombo mission has successfully completed its fourth of six gravity assist flybys at Mercury, capturing images of two special impact craters as it uses the little planet’s gravity to steer itself on course to enter orbit around Mercury in November 2026.

The closest approach took place at 23:48 CEST (21:48 UTC) on 4 September 2024, with BepiColombo coming down to around 165 km above the planet’s surface. For the first time, the spacecraft had a clear view of Mercury’s south pole.

To commemorate the 25th anniversary of NASA's Chandra X-ray Observatory, scientists have rereleased new "sonified" images of nearby objects, including the supernova remnant Cassiopeia A.

Energy-packed plasma waves pump enough energy into streams of solar wind to propel them to their unexpectedly high speeds, observations by two sun-studying spacecraft suggest.

The Universe often puts on a good show for us down here on Earth but one of the best spectacles must be a meteor shower. We see them when particles, usually the remains of comets, fall through our atmosphere and cause the atmosphere to glow. We see them as a fast moving streak of light but a new paper has suggested that the meteor showers we see can explain the sizes of the particles that originally formed the comet from where they came. 

Comets are mostly composed of ice but with a little rock mixed in for good measure. They’ve often been called dirty snowballs to describe this mix of ice and rock. They travel around the Sun in elongated, elliptical orbits which bring them close to the Sun. The intense heat from the Sun causes the ice to instantly turn into a gas in a process known as sublimation which releases the trapped dust. The pressure from the Sun known as the solar wind presses against the gas and dust released from a comet to produce the tail which always points away from the Sun. 

A recent animation of Comet 12P. Image credit: Michael Jaeger.

As the comet travels around the Solar System, it deposits debris along its orbit almost like a trail of celestial breadcrumbs. The debris at this stage is known as meteoroids but, if the Earth travels through it then they create the stunning meteors that we see streak across the sky. The Earth passes through the debris field from a number of comets on a regular, annual basis and this gives rise to the regular meteor showers we see such as he Perseids or Leonids. 

A Geminid meteor outburst from 2020. Image credit and copyright: Jeff Sullivan

A team of 45 researchers have been studying meteor showers and have discovered something rather curious. They have found that not all comets crumble in the same way as they approach the Sun. The team studied 47 young meteor showers by using special low light video cameras all over the world. The cameras measured the path of the meteors enabling the team to work out how high up they were when they first light up and how they then slowed down in the atmosphere. They were also able to measure the composition enabling them to deduce the size of the particles.

In a paper published in the journal Icarus, the team theorised that a comet will simply crumble into the size of the ‘pebbles’ they are made of. This does seem to make complete sense given that the comets form as chunks of dust, rock and ice. More ice will slowly form as the comet orbits out in the dark cold reaches of the Solar System but as it heats on its journey inwards, it will just fall apart again as the ice sublimates. 

The results of the paper showed that longer period comets, such as those originating in the Oort Cloud generally crumble into sizes of particulates indicative of slow and gentle accretion conditions.  The resultant meteoroids have a lower density and tend to only brighten deeper into the Earth’s atmosphere. Comets from the Jupiter-family on the other hand crumble up into smaller, denser meteoroids with 8% more solid material on average.

There are a few meteor showers that originate from asteroids and these too have been studied. The team found that they tend to produce meteor showers with smaller particles that have evidence of aggressive fragmentation during their formation. The team acknowledge there will be exceptions to their findings but it their study has helped to build a more fuller picture of the early stages of the evolution of the Solar System and to the nature of comets that grant us the beauty of meteor showers.

Source : Meteor showers shed light on where comets formed in the early solar system

The post Explaining Different Kinds of Meteor Showers. It’s the Way the Comet Crumbles appeared first on Universe Today.

Google has built a quantum computer that makes fewer errors as it is scaled up, and this may pave the way for machines that could solve useful real-world problems for the first time

Google has built a quantum computer that makes fewer errors as it is scaled up, and this may pave the way for machines that could solve useful real-world problems for the first time

Training in symbolic logic is critical in many careers, for responsible citizenship and better lives. It is also an underexploited antidote to today’s bizarre conspiracy thinking

As a result of phone bans, millions of students will stuff their phones into fabric pouches this fall

Starliner's astronauts will spend at least 8 months in space, longer than a typical ISS crew. But numerous other astronauts have safely spent a year on the ISS, or even longer.

Southern Moonscape

Video: 00:14:09

The Copernicus Sentinel-2C satellite lifted off on 5 September at 03:50 CEST (4 September 22:50 local time) aboard the last Vega rocket, flight VV24, from Europe’s Spaceport in French Guiana.

Sentinel-2C will continue the legacy of delivering high-resolution data that are essential to Copernicus – the Earth observation component of the EU Space Programme. Developed, built and operated by ESA, the Copernicus Sentinel-2 mission provides high-resolution optical imagery for a wide range of applications including land, water and atmospheric monitoring.

Sentinel-2C was the last liftoff for the Vega rocket – after 12 years of service this was the final flight, the original Vega is being retired to make way for an upgraded Vega-C.

The third Copernicus Sentinel-2 satellite launched today aboard the final Vega rocket from Europe’s Spaceport in French Guiana. Sentinel-2C will continue providing high-resolution data that is essential to Copernicus – Europe’s world leading Earth observation programme.

Sentinel-2C launched into orbit on 5 September at 03:50 CEST (4 September 22:50 local time) and separated from the Vega rocket at approximately 04:48 CEST.

The discovery of dark oxygen at an abyssal plain on the ocean floor generated a lot of interest. Could this oxygen source support life in the ocean depths? And if it can, what does that mean for places like Enceladus and Europa?

What does it mean for our notion of habitability?

Oxygen is key to complex life on Earth, where photosynthesis generates most of it. The Great Oxygenation Event (GOE), which occurred about 2.5 billion years ago, led to the development of complex life and changed Earth forever. In the GOE, the oxygen was generated by living things.

Our notions of habitability rest on a planet’s proximity to its star, and part of that is because we know that the Sun drives life on Earth by allowing water to remain liquid and providing energy for organisms. But dark oxygen on the ocean floor is strictly abiotic, meaning no life was involved in its production and sunlight isn’t involved.

In recent years, we’ve learned that other Solar System bodies, far beyond the circumstellar habitable zone, could be habitable. The icy ocean moons of Europa, Ganymede, and Enceladus may harbour vast, warm oceans under frigid caps of ice. If Earth produces dark oxygen on its ocean floors, maybe these worlds do, too.

New research examines Earth’s dark oxygen and what it might mean for biology here and on other worlds. It’s titled “Dwellers in the Deep: Biological Consequences of Dark Oxygen.” The lead author is Manasvi Lingam from the Department of Aerospace, Physics, and Space Sciences at the Florida Institute of Technology. The research is awaiting peer review.

Dark oxygen comes from metal deposits called polymetallic nodules. These nodules generate enough electricity to drive electrolysis, which splits water molecules apart and releases oxygen. The amount of oxygen is not large, but it’s there, and it’s measurable.

By Hannes Grobe/AWI – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=104756773

“The striking recent putative detection of “dark oxygen” (dark O2) sources on the abyssal ocean floor in the Pacific at ~4 km depth raises the intriguing scenario that complex (i.e., animal-like) life could exist in underwater environments sans oxygenic photosynthesis,” the authors write.

The amount of dark oxygen in the ocean is small, which limits the size of organisms. Organisms use oxygen through diffusion and circulation, and oxygen levels place restraints on the sizes of both types.

Diffusion is a simple process in which nutrients, waste, and water diffuse through a few layers of tissue. Circulation is more complex and involves a heart pumping fluid to an organism’s cells, delivering nutrients and removing waste. The amount of environmental oxygen places limits on the sizes of both types of organisms.

“The maximal sizes attainable by idealized unicellular or multicellular organisms (i.e., constrained by internal or external diffusion processes) for the estimated concentrations of dark O2 may be ~ 0.1–1 mm.,” the authors write.

For animals with circulation systems, the upper size boundary is higher but still limited.

“In contrast, the upper-size bounds of organisms with internal circulation systems for the distribution of oxygen could range between ~ 0.1 cm to ~ 10 cm, with the latter threshold falling under the umbrella of “megafauna,” the researchers explain.

Aside from the size of individual organisms, there’s the overall biomass density. In an optimistic scenario, the researchers report that biomass density could exceed the reported density. “Under optimistic circumstances, the biomass densities might reach as high as ~ 3–30 g m?2, in principle exceeding the reported macrofaunal densities at depths of ~ 4 km in global deep-sea surveys,” the authors write.

This work inspires a multitude of questions. We know that microorganisms in groundwater use dark oxygen. What types of microorganisms have adapted to these ocean dark oxygen environments? What about their metabolism allows them to live there? Have larger organisms adapted to these environments? Did organisms in these environments play a role in the evolution of life on Earth?

The discovery also compels us to consider its implications for astrobiology. On Earth, abyssal deep sea plains represent about 70% of the ocean floor, making them the largest ecosystem on Earth. Even with a low biomass density, the region is significant.

This cross-section of an oceanic basin shows the relationship of the abyssal plain to a continental rise and an oceanic trench. On Earth, 70% of the sea floor is abyssal plain, making it the largest ecosystem on Earth. Image Credit: By Chris_huh – Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=1812130

When considering the habitability of the ocean moons, we’re at a disadvantage. We don’t know what the sea floors look like on these bodies. In fact, despite all of the enthusiasm, we don’t even know for certain if these moons have oceans. We also don’t know if the oceans, if any of them exist, can produce polymetallic nodules that generate dark oxygen.

However, there are other ways dark oxygen can be generated without nodules. One of them is radiolysis.

Radiolysis is the breaking apart of molecules by ionizing radiation, and there’s plenty of that in the vicinity of Jupiter. Spacecraft have spotted O2 trapped in bubbles on Europa, Ganymede, and Callisto. Does that mean it’s available for life that might exist in their hypothetical oceans?

Radiation from Jupiter can break apart molecules on Europa’s surface. This can free oxygen, which could percolate in brines through the surface into the ocean under the ice. Credit: NASA/JPL-Caltech

“The production of oxidants on the surface and their delivery to the ocean can effectively input O2 to the latter even sans photosynthesis,” the authors explain. Europa’s icy shell isn’t all solid ice. Scientists think that briny liquid can percolate through the ice, and that could potentially deliver surface dark oxygen to the ocean.

There’s a third pathway for dark oxygen called microbial dismutation. Though it’s biotic, it doesn’t rely on photosynthesis. It could be an overlooked source of oxygen.

The evidence we have so far says that worlds like Earth are extremely rare, while environments like Europa could be widespread. “To round off our preliminary venture into this eclectic subject, we reiterate our
prefatory statement that marine habitable settings implausible for photosynthesis, especially on icy worlds with subsurface oceans, are likely widespread in the Universe,” the authors write in their conclusion.

“Therefore, if dark oxygen production is feasible and commonplace on this class of worlds – whether via seawater electrolysis or the prior two routes – then our analysis may broadly encapsulate the profound consequences of dark oxygen for the prevalence of abiogenesis, complex multicellularity, and perhaps even technological intelligence in the Cosmos,” the authors explain.

The fact that we’ve only now discovered dark oxygen on the ocean floor should make us all pause. We’re discovering things about nature that could be critical in the search for life and habitable worlds. If we can confirm that the so-called ocean moons really do have oceans and that dark oxygen is either produced in or transported to those oceans, then we have to adapt our thinking about habitability. Proximity to a star may not be critical, which would simultaneously broaden our understanding while deepening the mystery of life in the cosmos.

That’s the intriguing part of science. It’s equal part mysteries and answers.

The post Dark Oxygen Could Change Our Understanding of Habitability appeared first on Universe Today.

Chinese astronauts aboard the Tiangong space station are studying microbes, to help determine if some of Earth's early lifeforms can handle a simulated cosmic environment.