A pulsar orbited by a white dwarf star, which are both orbited by another white dwarf, provide confirmation of the principle of universality of free fall

RELATED: Ben Lecomte Sets Out to Become the First Person to Swim Across the Pacific Ocean

Download 195.97 Kb.
Size195.97 Kb.
1   2   3   4   5   6

RELATED: Ben Lecomte Sets Out to Become the First Person to Swim Across the Pacific Ocean

Coastal areas and consequently marine turtle nesting environment exposed to microplastic may also be harmed by toxic chemicals that leach out of the microplastics when they are heated.

Given the potential impacts of microplastic on marine turtle incubating environment, we did a study to determine the microplastic exposure of the 10 most important nesting sites in Florida for the Northern Gulf of Mexico loggerhead subpopulation. Microplastic was found at all nesting sites, with the majority of pieces located at the dunes, the primary site where turtles nest.

We took several samples of sand at each nesting site during the Northern Hemisphere summer months, May to August, which is when turtles are nesting in the region.

We are still unsure what the implications of these exposures are, and how much microplastic is needed to change the temperature of the nesting grounds. So, this summer we are expanding our experiments to explore how different densities and types of microplastic can affect the temperature of nesting grounds.

Regardless of the implications, it is important to consider that any alteration to our natural environment may be detrimental to species that rely on them. The good news is that there are several easy ways to reduce microplastic.

The research was conducted by undergraduate student Valencia Beckwith and Mariana Fuentes.

Originally published at The Conversation.


Wed, 06 Jun 2018 15:47:04 -0500
The gravitational pull of thousands of small space rocks, rather than a massive, unseen planet, could be creating the odd orbits of objects in the Kuiper Belt.no-reply@thrillist.com Nora Taylor Redd, Space.comNora Taylor Redd, Space.comhttp://www.seeker.com/space/the-gravity-from-small-objects-not-planet-nine-explains-weird-orbits?utm_medium=RSS&utm_source=feeds Credit: NASA/JPL-Caltech
DENVER — Small but rowdy space rocks pushing and jostling one another may have created the unusual orbits some astronomers cite as the signature of the hypothesized "Planet Nine," a new study suggests.

To date, researchers have discovered more than 2,300 bodies in the cold, distant realm beyond Neptune's orbit. The huge number of these trans-Neptunian objects (TNOs) makes it computationally intensive to model the evolution of their orbits. However, the new study suggests that the complex gravitational dances among TNOs can be enough to send some, such as the dwarf planet Sedna, onto odd and intriguing paths.

"The picture we have in our head is a lot of little moons floating around the solar system, interacting with comets," Ann-Marie Madigan, an assistant professor in the department of astrophysical and planetary sciences at the University of Colorado, Boulder (CU Boulder), said during a news conference today June 4. [The Search for Planet Nine in Pictures]

Madigan and CU Boulder undergraduate student Jacob Fleisig presented the results here at the 232nd meeting of the American Astronomical Society, in Denver.

No need for Planet Nine?
The Kuiper Belt, the region immediately beyond Neptune, harbors TNOs of many sizes. The largest is Pluto, which was discovered more than 60 years before any of the others.

Some TNOs are "detached objects," which orbit so far from the sun that they're not appreciably affected by the gravity of Neptune or any other known planet. Perhaps the most famous of these is Sedna, which takes 11,400 years to make a single orbit and never comes closer to the sun than 20 times farther out than Pluto.

In 2016, astronomers Konstantin Batygin and Mike Brown announced that a distant undiscovered planet could have created the unusual signatures of some TNO orbits in the Kuiper Belt and sent Sedna and other detached objects out to even more distant realms. Batygin and Brown calculated that this world, dubbed Planet Nine, may be 10 times more massive than Earth and orbit the sun about 20 times farther away than Neptune does.

But not everybody is on board with the Planet Nine hypothesis. The skeptics include Madigan and Fleisig, who, along with study co-author Alexander Zderic, a UC Boulder graduate student, think they've found an alternate solution to the weird orbital signatures.

According to the researchers' simulations, the TNOs move like hands on a clock, with the most massive objects moving slowly, like the hour hand, and the smaller ones ticking along quickly, like the minute hand. The result is that the smaller bodies pile up quickly — and their accumulated gravity is strong enough to reshape the paths of larger TNOs that get close.

Eventually, the larger chunks wind up in extreme orbits, just like Sedna.

"They are what's causing this detachment, and not an unseen ninth planet," Fleisig said during the news conference. [Our Solar System: A Photo Tour of the Planets]

The gravity of the situation
If this is the answer to the TNO puzzle, why hasn't anyone else noticed? Madigan and Fleisig said the problem is one of scale. It's computationally expensive to include a mass for each of the thousands of TNOs, so most simulations leave them massless, which negates how they interact gravitationally. [Trans-Neptunian Objects in the Extreme Outer Solar System (Infographic)]

"The crucial difference is to include their mass in the simulation," Madigan told Space.com.

The researchers didn't add mass to all of the TNOs, only to about 400. But that was enough to send the most massive objects into bizarre orbits.

The collective-gravity hypothesis isn't a silver bullet, however. For example, there's still "clustering in pomega," which Madigan described as the odd fact that the orbits of the detached objects all tilt the same way.

"Planet Nine explains this really well, and we do not," Madigan said.

Ironically, while the new research discounts the need for an undiscovered planet, it requires the presence of thousands of smaller unseen objects.

"The handful we've seen is not enough," Fleisig said.

Madigan told Space.com that the early solar system was filled with enough debris to build up tens of Earths, but in far smaller pieces. Because most of the objects are modeled massless, most studies eject the bulk from the solar system. Adding mass means that more of that material could have stuck around, their smaller size keeping them from being detected.

"The objects we've seen so far are just the tip of the iceberg," Fleisig said.

While the small size of most TNOs makes them a challenge to detect, their motion makes it even harder. Usually, the larger an object is, the easier it is to discover. But because the largest objects are hurled into the most eccentric orbits, they become more difficult to find, the researchers said.

In addition, the presence of the small handful already spotted suggests a larger population, Madigan said.

"If there are only 10 out there, and we detected 10, it's bizarrely lucky," she said.

Death to the dinosaurs
The gravitational interactions among TNOs may also explain another strange event: the extinction of the nonavian dinosaurs about 65 million years ago.

Previous studies have suggested that mass extinctions may occur with regularity, and some researchers have linked this perceived periodicity to pulses of comet or asteroid strikes. What could cause a cyclical rain of death from above? Other researchers have cited dark matter or the sun's hypothesized unseen companion star, Nemesis, as candidates. (Nemesis has never been spotted and is dismissed by most scientists.)

Madigan called this impact-extinction-cycle idea "geology's Planet Nine" — a nebulous connection she said is under debate in geologic circles.

If the small gravitational interactions among TNOs are hurling objects like Sedna outward, they could also send some of the rocks into the inner solar system. Fleisig said the team's model creates periodic comet showers for the rocky planets, including Earth. While the researchers couldn't directly connect their observations to the collision that wiped out the dinosaurs and most life on Earth, Fleisig called the possibility "tantalizing."

"It's exciting and suggestive," Madigan said.

Originally published on Space.com.

Editor's Recommendations
'Planet Nine': Facts About the Mysterious Solar System World (Infographic)
Solar System Explained From the Inside Out (Infographic)
Planet Nine? 'Extreme' Objects Hint at More Evidence of Possible Unseen World

Wed, 06 Jun 2018 14:48:41 -0500
Seeker's Bad Science podcast explores the scientific principles behind your favorite sci-fi films.no-reply@thrillist.com Glenn McDonaldGlenn McDonaldhttp://www.seeker.com/culture/robots-versus-monsters-the-real-science-behind-pacific-rim?utm_medium=RSS&utm_source=feeds
Policy wonks take note: If and when the planet is threatened by Godzilla-type monsters rising from the seas, giant humanoid robots may not be the most efficient defense policy.

That's among the many conclusions reached in the latest episode of Bad Science, Seeker's podcast dedicated to exploring the real scientific principles behind blockbuster movies and popular genre films.

In this week's episode, host Ethan Edenburg is joined by podcaster and comic Jon Gabrus and chemical engineer Mara Tsudis to break down the 2013 sci-fi freakout Pacific Rim. Set on a near-future Earth, director Guillermo Del Toro imagines a war between humans and Kaiju – colossal cosmic horrors ported in through an dimensional window at the bottom of the Pacific Ocean.

To fight off the rampaging baddies, humankind has developed and deployed the Jaegers, or  â€œHunters” — towering robots controlled by human pilots whose minds are linked directly to their massive machines. The existential threat behind Pacific Rim is entirely fictional (we hope) but the film engages real scientific principles. Well, pseudo-scientific principles. In any case, it never hurts to be prepared.

Science guest Tsudis's background in chemistry, metallurgy, and industrial engineering comes in handy when discussing the creation of the Jaeger bots. Could we really build 20-story titanium robots? What is titanium anyway? What are alloys? Tsudis raises critical questions about conductivity points and the corrosive effects of saltwater. These are the kinds of things we should be thinking about if we're going to be fighting off Lovecraftian ocean beasties from alternate dimensions.

Later in the podcast, the crew questions the wisdom of designing bipedal bots for offshore battles and the very real dilemma of overcoming OSHA regulations in the giant robot industry. It's all in the spirit of reckless conjecture, of course. We're at the movies, after all, and movies have different priorities.
“An engineer's job is to look at a problem and come up with the most creative ways to solve it, then find the most practical way out of those creative ways,” Tsudis advises. “This isn't the most creative way, and it's not the most practical way. But it might be the coolest-looking way.”
Tune in for this week's episode and be sure to check the back catalog of Bad Science in which experts explore the real science behind other sci-fi classics including Back to the Future, Alien, and The Empire Strikes Back.

Tue, 05 Jun 2018 16:31:46 -0500
Temperatures on the island after the last ice age were higher than previously thought, a finding that will help estimate the impact of a warming climate.no-reply@thrillist.com Matt SmithMatt Smithhttp://www.seeker.com/earth/greenland-bugs-yield-clues-to-the-impacts-of-climate-change?utm_medium=RSS&utm_source=feeds Credit: Yarrow Axford, Northwestern University
Flying bugs trapped deep in the frozen mud covering Greenland have pointed researchers to new clues about the country’s climate, suggesting the now-icebound island was once warmer than previously believed.  

In the centuries that followed the last ice age and in the millenia between the last two, Greenland could have seen summer highs between 10 and 15 degrees warmer than today, according to a new study led by researchers at Northwestern University in Illinois.

Core samples taken from the mud of a lake bed in northwestern Greenland, just beyond the edge of the ice sheet and largely undisturbed by its historical ebb and flow, revealed large numbers of preserved insects known as phantom midges and a fly species known as chironomids. Those species today usually live well south of Greenland, but the numbers found in the sediment cores taken by the Northwestern team were comparable to populations seen in the Canadian Atlantic provinces.

As far as the team could tell, the phantom midge hasn’t been seen in Greenland before now.

“We think this is the first time anyone has reported it in ancient sediments or modern lakes there," Yarrow Axford, the study's senior author, said in a statement accompanying the findings. "We were really surprised to see how far north it migrated."

The findings suggest temperatures in Greenland’s summer might have ranged into the 50s Fahrenheit, or in the low teens Celsius — well above today’s averages of around 40°F.

Credit: Alex P. Taylor
With the Arctic warming today at twice the rate of the rest of the globe, Greenland is under intense scientific scrutiny. About four-fifths of the island is covered by a sheet of ice more than a mile thick. That’s enough frozen water to raise global sea levels by about six meters (20 feet) if it melted — which it is, at a slow but accelerating rate.

Figuring out what Greenland’s climate was like in the past can help scientists figure out what may happen to it in the future as planet-warming carbon dioxide and other gases build up in Earth’s atmosphere. That data collected by studies like the Northwestern study can be fed into computer models to help fine-tune those estimates.

“These findings may portend large future warming in this high-latitude region,” the authors conclude.

RELATED: Ancient Icelandic Volcanoes May Have Hastened Ice Age Melting

In the period between the last two ace ages — roughly 11,000 to 116,000 years ago — sea levels were as much as 30 feet higher than they are today.

"Northwest Greenland might feel really remote, but what happens to that ice sheet is going to matter to everyone in New York City, Miami and every coastal city around the world," Axford said.

Tue, 05 Jun 2018 15:06:50 -0500

Share with your friends:
1   2   3   4   5   6

The database is protected by copyright ©dentisty.org 2019
send message

    Main page