adplus-dvertising
Connect with us

Science

This is what “war in space” probably would look like in the near future – Ars Technica

Published

 on


Enlarge / Anti-Satellite Weapons from Mission Shakti are displayed during Republic Day Parade on January 26, 2020 in New Delhi, India.
Ramesh Pathania/Mint via Getty Images

The creation of the US Space Force has conjured up all manner of fanciful notions about combat in space. Will military satellites act like X-wings and Tie Fighters, zipping around and shooting at one another? Or perhaps will larger ships akin to the USS Enterprise fire photon torpedoes at enemy warbirds?

Hardly. But even those with more realistic expectations for what could happen if nations went to war in space—perhaps satellites using orbital kinetic weapons to attack other satellites?—may not fully appreciate the physics of space combat. That’s the conclusion of a new report that investigates what is physically and practically possible when it comes to space combat.

Published by The Aerospace Corporation, The Physics of Space War: How Orbital Dynamics Constrain Space-to-Space Engagements lays out several basic concepts that are likely to govern any space combat for the foreseeable future. All of the physical constraints suggest battles will need to be planned far in advance.

Unlike a war on Earth, which typically involves an effort by opposing forces to dominate a physical location, satellites in orbit do not occupy a single location. Therefore, the report authors Rebecca Reesman and James Wilson write, controlling space does not necessarily mean physically conquering sectors of space.

Rather, control over the high ground involves reducing or eliminating adversary satellite capabilities while ensuring one retains the ability to freely operate their own space capabilities for communications, navigation, observation, and all the other increasingly essential ways in which militaries rely on space.

When considering how to control space, the authors lay out the ways in which space combat is counter-intuitive for policymakers and strategists.

  • Satellites move quickly, but predictably:  Satellites in commonly used circular orbits move at speeds between 3km/s and 8km/s, depending on their altitude. By contrast, an average bullet only travels about 0.75km/s. They are here, and then gone.
  • Space is big: The volume of space between low-earth orbit and geostationary orbit is about 200 trillion cubic kilometers. That is 190 times larger than the volume of Earth.
  • Timing is everything: Within the confines of the atmosphere, airplanes, tanks, and ships can nominally move in any direction. Satellites do not have that freedom. Due to the gravitational pull of Earth, satellites are always moving in either a circular or elliptical path, constantly in free-fall around the Earth. Getting two satellites in the same spot is not intuitive. Therefore, it requires careful planning and perfect timing.
  • Satellites maneuver slowly: While satellites move quickly, space is big, and that makes purposeful maneuvers seem relatively slow. Once a satellite is in orbit, it requires time and a large amount of delta-V to perform phasing maneuvers.

Given all of this, for engagements in space, maneuvers and actions will have to be planned far in advance, Reesman said in an interview. “Any conflict in space will be much slower and more deliberate than a Star Wars scene,” she said. “It requires a lot more long-term thinking and strategic placement of assets.”

In a perfect world, space might be viewed as a sanctuary. But since the mid-1970s and the advent of anti-satellite weapons in the Soviet Union and the United States, space has been treated as a contested domain by the United States, the Soviet Union, and other emerging powers. While no shooting wars have broken out in space, the ability to take down space weapons has been seen by new powers such as China (in 2007) and India (in 2019) as a means to demonstrate their capabilities.

In addition to ground-based missiles, the report identifies several ways in which satellites might be attacked. Radio signals can be used to jam an opponent’s satellites, or spoof them by sending harmful commands. This would be an extension of electronic warfare already used in naval and air battles.

Some nations, such as France, have gone so far as to talk about deploying weapons in space to protect their own satellites. However, the authors suggest that satellites using kinetic weapons to shoot down opposing satellites seems unlikely for now, given the extraordinary energy required to maneuver an orbital weapon into a proper trajectory. More likely would be a “T-bone” collision between satellites, which does not require plane matching but rather occurs when two orbits cross.

Nations do have a strong incentive to not destroy other satellites because of the potential to create hazardous debris that would potentially affect all nations’ assets in space—and debris generated in space has a lasting effect. However, in the immediacy of war, a nation may decide it is worth permanently losing access to some slots in geostationary orbit, due to debris, in order to win a ground-based war.

And what about the Moon? In the television show on Netflix, Space Force, US and Chinese troops get into a ground-based combat on the surface of the Moon. It all seems pretty ridiculous, considering the expense of transporting all that material to the lunar surface. And yet—and yet—from a geopolitical standpoint it does seem plausible that we could see humans fighting over the Moon in the not-too-distant future.

So what do the study authors think about hand-to-hand fighting on the Moon, with its low gravity and vacuum? “I would think you’re more likely to take out the rockets on the way up,” Wilson said.

Let’s block ads! (Why?)

728x90x4

Source link

Continue Reading

News

Here’s how Helene and other storms dumped a whopping 40 trillion gallons of rain on the South

Published

 on

 

More than 40 trillion gallons of rain drenched the Southeast United States in the last week from Hurricane Helene and a run-of-the-mill rainstorm that sloshed in ahead of it — an unheard of amount of water that has stunned experts.

That’s enough to fill the Dallas Cowboys’ stadium 51,000 times, or Lake Tahoe just once. If it was concentrated just on the state of North Carolina that much water would be 3.5 feet deep (more than 1 meter). It’s enough to fill more than 60 million Olympic-size swimming pools.

“That’s an astronomical amount of precipitation,” said Ed Clark, head of the National Oceanic and Atmospheric Administration’s National Water Center in Tuscaloosa, Alabama. “I have not seen something in my 25 years of working at the weather service that is this geographically large of an extent and the sheer volume of water that fell from the sky.”

The flood damage from the rain is apocalyptic, meteorologists said. More than 100 people are dead, according to officials.

Private meteorologist Ryan Maue, a former NOAA chief scientist, calculated the amount of rain, using precipitation measurements made in 2.5-mile-by-2.5 mile grids as measured by satellites and ground observations. He came up with 40 trillion gallons through Sunday for the eastern United States, with 20 trillion gallons of that hitting just Georgia, Tennessee, the Carolinas and Florida from Hurricane Helene.

Clark did the calculations independently and said the 40 trillion gallon figure (151 trillion liters) is about right and, if anything, conservative. Maue said maybe 1 to 2 trillion more gallons of rain had fallen, much if it in Virginia, since his calculations.

Clark, who spends much of his work on issues of shrinking western water supplies, said to put the amount of rain in perspective, it’s more than twice the combined amount of water stored by two key Colorado River basin reservoirs: Lake Powell and Lake Mead.

Several meteorologists said this was a combination of two, maybe three storm systems. Before Helene struck, rain had fallen heavily for days because a low pressure system had “cut off” from the jet stream — which moves weather systems along west to east — and stalled over the Southeast. That funneled plenty of warm water from the Gulf of Mexico. And a storm that fell just short of named status parked along North Carolina’s Atlantic coast, dumping as much as 20 inches of rain, said North Carolina state climatologist Kathie Dello.

Then add Helene, one of the largest storms in the last couple decades and one that held plenty of rain because it was young and moved fast before it hit the Appalachians, said University of Albany hurricane expert Kristen Corbosiero.

“It was not just a perfect storm, but it was a combination of multiple storms that that led to the enormous amount of rain,” Maue said. “That collected at high elevation, we’re talking 3,000 to 6000 feet. And when you drop trillions of gallons on a mountain, that has to go down.”

The fact that these storms hit the mountains made everything worse, and not just because of runoff. The interaction between the mountains and the storm systems wrings more moisture out of the air, Clark, Maue and Corbosiero said.

North Carolina weather officials said their top measurement total was 31.33 inches in the tiny town of Busick. Mount Mitchell also got more than 2 feet of rainfall.

Before 2017’s Hurricane Harvey, “I said to our colleagues, you know, I never thought in my career that we would measure rainfall in feet,” Clark said. “And after Harvey, Florence, the more isolated events in eastern Kentucky, portions of South Dakota. We’re seeing events year in and year out where we are measuring rainfall in feet.”

Storms are getting wetter as the climate change s, said Corbosiero and Dello. A basic law of physics says the air holds nearly 4% more moisture for every degree Fahrenheit warmer (7% for every degree Celsius) and the world has warmed more than 2 degrees (1.2 degrees Celsius) since pre-industrial times.

Corbosiero said meteorologists are vigorously debating how much of Helene is due to worsening climate change and how much is random.

For Dello, the “fingerprints of climate change” were clear.

“We’ve seen tropical storm impacts in western North Carolina. But these storms are wetter and these storms are warmer. And there would have been a time when a tropical storm would have been heading toward North Carolina and would have caused some rain and some damage, but not apocalyptic destruction. ”

___

Follow AP’s climate coverage at https://apnews.com/hub/climate

___

Follow Seth Borenstein on Twitter at @borenbears

___

Associated Press climate and environmental coverage receives support from several private foundations. See more about AP’s climate initiative here. The AP is solely responsible for all content.

Source link

Continue Reading

Science

‘Big Sam’: Paleontologists unearth giant skull of Pachyrhinosaurus in Alberta

Published

 on

 

It’s a dinosaur that roamed Alberta’s badlands more than 70 million years ago, sporting a big, bumpy, bony head the size of a baby elephant.

On Wednesday, paleontologists near Grande Prairie pulled its 272-kilogram skull from the ground.

They call it “Big Sam.”

The adult Pachyrhinosaurus is the second plant-eating dinosaur to be unearthed from a dense bonebed belonging to a herd that died together on the edge of a valley that now sits 450 kilometres northwest of Edmonton.

It didn’t die alone.

“We have hundreds of juvenile bones in the bonebed, so we know that there are many babies and some adults among all of the big adults,” Emily Bamforth, a paleontologist with the nearby Philip J. Currie Dinosaur Museum, said in an interview on the way to the dig site.

She described the horned Pachyrhinosaurus as “the smaller, older cousin of the triceratops.”

“This species of dinosaur is endemic to the Grand Prairie area, so it’s found here and nowhere else in the world. They are … kind of about the size of an Indian elephant and a rhino,” she added.

The head alone, she said, is about the size of a baby elephant.

The discovery was a long time coming.

The bonebed was first discovered by a high school teacher out for a walk about 50 years ago. It took the teacher a decade to get anyone from southern Alberta to come to take a look.

“At the time, sort of in the ’70s and ’80s, paleontology in northern Alberta was virtually unknown,” said Bamforth.

When paleontogists eventually got to the site, Bamforth said, they learned “it’s actually one of the densest dinosaur bonebeds in North America.”

“It contains about 100 to 300 bones per square metre,” she said.

Paleontologists have been at the site sporadically ever since, combing through bones belonging to turtles, dinosaurs and lizards. Sixteen years ago, they discovered a large skull of an approximately 30-year-old Pachyrhinosaurus, which is now at the museum.

About a year ago, they found the second adult: Big Sam.

Bamforth said both dinosaurs are believed to have been the elders in the herd.

“Their distinguishing feature is that, instead of having a horn on their nose like a triceratops, they had this big, bony bump called a boss. And they have big, bony bumps over their eyes as well,” she said.

“It makes them look a little strange. It’s the one dinosaur that if you find it, it’s the only possible thing it can be.”

The genders of the two adults are unknown.

Bamforth said the extraction was difficult because Big Sam was intertwined in a cluster of about 300 other bones.

The skull was found upside down, “as if the animal was lying on its back,” but was well preserved, she said.

She said the excavation process involved putting plaster on the skull and wooden planks around if for stability. From there, it was lifted out — very carefully — with a crane, and was to be shipped on a trolley to the museum for study.

“I have extracted skulls in the past. This is probably the biggest one I’ve ever done though,” said Bamforth.

“It’s pretty exciting.”

This report by The Canadian Press was first published Sept. 25, 2024.

The Canadian Press. All rights reserved.

Source link

Continue Reading

News

The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

Published

 on

 

TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.

Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.

Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.

The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.

The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.

It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.

Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.

Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.

Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.

Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.

Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.

The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”

The Canadian Press. All rights reserved.

Source link

Continue Reading

Trending