Dying Star Offers Glimpse of Earth's Doomsday in 5B Years
Five billion years from now, our sun will die. After running out of hydrogen fuel, it will start burning heavier and heavier elements in its fusion core, causing its body to bloat, shedding huge quantities of material into space via violent stellar winds. During this time, our star will expand around 100 times bigger than it is now, becoming what is known as a "red giant." This dramatic expansion will engulf Mercury and Venus, the two closest planets to the sun.
But what is less clear is what will happen to Earth — will our planet go the way of Mercury and Venus and succumb to an ocean of superheated plasma? Or will our planet escape the worst of the sun's death throes to continue orbiting the tiny white dwarf star that will be left behind?
"We already know that our sun will be bigger and brighter [when entering the red giant phase], so that it will probably destroy any form of life on our planet," said Leen Decin, of the KU Leuven Institute of Astronomy, in a statement. "But will the Earth's rocky core survive the red giant phase and continue orbiting the white dwarf?"
With the help of the most powerful radio observatory on the planet, astronomers could soon have a clue by looking at a nearby star system that resembles how our solar system will look when the sun begins to die.
L2 Puppis is an evolved star located over 200 light-years from Earth. Though this seems far away, it's pretty much on our cosmic doorstep and well within the resolving power of the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. Through precise measurements of the star, astronomers have deduced its mass and age, realizing that it is (or was) a sun-like star that's now 10 billion years old. It's also a prime example of a planetary nebula in the making.
Like our sun five billion years in the future, L2 Puppis is ripping itself apart, blasting huge quantities of gas into space. This process creates a massive glowing cloud and this particular planetary nebula resembles a beautiful cosmic butterfly (pictured above by the ESO's Very Large Telescope).
But that's not all. According to the new study published in the journal Astronomy & Astrophysics, L2 Puppis also appears to have a planet in tow, roughly 300 million kilometers from the star. Though this distance is around twice the distance that Earth orbits the sun, it provides a very privileged view of a world orbiting a dying sun-like star. It's also an ominous preview of what's in store for Earth in a few billion years and the researchers hope to study this unfortunate planet as it experiences the wrath of L2 Puppis."We discovered that L2 Puppis is about 10 billion years old," said Ward Homan, also from KU Leuven. "Five billion years ago, the star was an almost perfect twin of our sun as it is today, with the same mass. One third of this mass was lost during the evolution of the star. The same will happen with our sun in the very distant future."
"Five billion years from now, the sun will have grown into a red giant star, more than a hundred times larger than its current size," said Decin. "It will also experience an intense mass loss through a very strong stellar wind. The end product of its evolution, 7 billion years from now, will be a tiny white dwarf star. This will be about the size of the Earth, but much heavier: one tea spoon of white dwarf material weighs about 5 tons."
Astronomers often look to the stars to better understand our own place in the galaxy. In this case, they've glimpsed the future and seen a key part of the life cycle of a sun-like star. They've also seen a true doomsday, an event so final that it wrecks our sun, taking the nearest planets with it. And though Earth may or may not be swallowed whole by the swelling stellar inferno, it will be sterilized of life — on our planet's roasted surface at least.
Rare Elizabethkingia Infections: Report Suggests More Than 1 Source
Exactly how 10 people in Illinois recently became infected with a rare bacterial illness called Elizabethkingia is still a mystery, but a new report finds that there were likely multiple sources for the infections.
The Illinois cases came to light after an outbreak of the bacteria sickened nearly 60 people in Wisconsin. To see if there were related cases in Illinois, the state's health department started an investigation, which revealed that at least 10 people in Illinois had been infected with the bacteria Elizabethkingia anophelis between June 2014 and March 2016.
Genetic testing showed that all 10 people were infected with the same strain of Elizabethkingia bacteria, but that this strain was different from the one that was causing illnesses in Wisconsin.
The illnesses in Illinois were highly fatal — seven of the 10 patients died, including six who died within a month of the time that their samples were tested by officials. Most of the patients were elderly and had at least one serious underlying health condition, the new report said. [6 Superbugs to Watch Out For]
All of the patients stayed in a hospital or nursing home during the month leading up to their positive test for Elizabethkingia, and some stayed at multiple hospitals during the course of their illness. In total, the 10 patients were cared for at 19 health care facilities, and most of the time, the patients didn't stay at the same hospital or nursing home as the others, the report said.
What's more, when officials asked the 19 health care facilities to report any cases of Elizabethkingia going back to 2012, they found that, on average, there were a total of 17Elizabethkingia infections per year, and that the average number of reported infections hadn't increased over the years.
This evidence does not support the idea that there was a sudden outbreak with a single source that sickened all the patients, the new report said. "Instead, this more likely represents ongoing sporadic infection among critically ill patients," the report said. [27 Oddest Medical Cases]
In addition, the researchers found that a previous Illinois outbreak of Elizabethkingia in 2012 to 2013 was also caused by a strain of bacteria that was very similar to the one that sickened the 10 patients in 2014 to 2016. Previously, health officials had thought the 2012 to 2013 outbreak was caused by a different species, called Elizabethkingia meningoseptica, but genetic testing showed that it was actually caused by Elizabethkingia anophelis.
The evidence "does point to distinct infection pathways," rather than a single source, said study researcher Livia Navon, a Centers for Disease Control and Prevention career epidemiology field officer at the Illinois Department of Public Health. Navon noted that the cases in the 2014 to 2016 cluster occurred over an extended period of time, and that few patients stayed at the same health care facility.
However, Navon said that much remains to be learned about these bacteria. "This does appear to be an opportunistic pathogen, i.e., affecting those with underlying health conditions/compromised immune systems," Navon told Live Science in an email. But "how individual patients … acquired the infection remains unknown," Navon said.
More research is needed to identify the infection's routes of transmission as well as factors that increase the risk of transmission, Navon said.
Inscription About Ancient 'Monkey Colony' Survives ISIS Attacks
A number of artifacts with inscriptions survived in the ancient Assyrian city of Nimrud, after the Islamic State group (also known as ISIS) destroyed the site.
The group targeted Nimrud, along with many other historical sites in Iraq and Syria, in an attempt to eradicate the history of the Assyrians, Shiite Muslims, Kurds and other peoples who live in Iraq and Syria. Countries and groups around the world have condemned this destruction of cultural heritage as a war crime.
Live Science showed photographs of some of the surviving inscriptions to scholars who translated or deciphered their meanings. The inscriptions tell a number of stories about the AssyrianKing Ashurnasirpal II (reign 883–859 B.C.), including the lands he conquered, the treasures he took, the palace he constructed and the ancestors he had.
All the surviving inscriptions found so far are written in the king's name, who turned Nimrud into his capital, building a vast palace in the city.
For instance, one story, inscribed on a statue that ISIS had tried to destroy, tells of a monkey colony that Ashurnasirpal II bred at Nimrud, stating that "herds of them in greatnumbers" lived at Nimrud during the king's reign. The inscription also tells of how Ashurnasirpal IIcaptured lions and kept them at Nimrud.
ISIS is under siege in Mosul, Iraq, and the group's remaining territories in Syria and Iraq are shrinking. So the monkey-colony inscription, and its tale of a time when Nimrud was a flourishing place filled with life, may survive far longer than the terrorist group that tried to destroy the statue bearing the inscription.
Nimrud's surviving inscriptions
The Iraq army retook the ancient city of Nimrud (also known as Calah or Kalhu) and surrounding areas on Nov. 13. Photographers who have visited the site, including photojournalist John Beck, have revealed the devastated remains of the ancient city. [Photos: Restoring Life to Iraq's Ruined Artifacts]
Grant Frame, a professor of Near Eastern languages and civilizations at the University of Pennsylvania who is an expert in Neo-Assyrian (ninth to sixth century B.C.) writing, examined some of the images captured by Beck and others. Frame told Live Science what the inscriptions, in general, say, noting that the surviving texts were duplicates of original versions; multiple copies with similar text were made in ancient times.
Monkey colony
The monkey colony is perhaps the most interesting story that Ashurnasirpal II tells. "The section here is a summary of the areas in the west — in Lebanon and Syria — who gave him tribute and the bringing of animals, monkeys and lions, to his capital city of Kalhu [another name for Nimrud]" said Frame.
At least eight "copies" of this monkey tale have been found in the past by archaeologists and historians, Frame said. The Assyrian historian Albert Kirk Grayson published a translation of these texts in 1991 in the book "Assyrian Rulers of the Early First Millennium BC" (University of Toronto Press).
Grayson translated these eight copies as reading, "I brought them [the monkeys] to my land Aššur. I bred herds of them in great numbers in Calah [and] displayed [them] to all the people of my land."
That mention of breeding in great numbers appears even though the translation mentions only the female monkeys. This means that the king already had, or also received, male monkeys and got the newly acquired female monkeys to breed with them. [Photos: New Archaeological Discoveries in Northern Iraq]
The inscription also mentions how Ashurnasirpal II captured lions. "With my outstretched hand and my fierce heart, I captured 15 strong lions from the mountains and forests. I took away 50 lion cubs. I herded them into Calah and the palaces of my land into cages," the inscription reads, as translated by Grayson.
Surviving ancient stories
The surviving inscriptions tell more tales from Ashurnasirpal II's reign, including the pride he felt for his palace.
Two of the surviving inscriptions, Frame said, preserve part of a text in which Ashurnasirpal II says that, at Nimrud, "I founded therein my lordly palace. I built this palace for the eternal admiration of rulers and princes [and] decorated it in a splendid fashion. I made [replicas of] all beasts of mountains and seas," placing the animal replicas in the palace doorways, as translated by Grayson.
ISIS largely destroyed the palace, although a bit of it appears to have survived, said Clemens Reichel, a curator at Toronto's Royal Ontario Museum, who viewed some of the photographs.
Two other inscriptions were found written on two surviving works of art — one showing a winged genie and the other, which is damaged, seeming to show multiple male individuals. These works of art contain a widely used ancient text that modern-day scholars sometimes call a "standard inscription," Frame said.
The two inscriptions indicate that Ashurnasirpal II owned these works of art: "[Property of] the palace of Ashurnasirpal, vice regent of Assur, chosen of the gods Enlil and Ninurta, beloved of the gods Anu and Dagan, destructive weapon of the great gods, strong king, king of the universe, king of Assyria," as translated by Grayson.
No comments:
Post a Comment