Scientists have discovered a "monster black hole" so massive that, in theory, it shouldn't exist
It’s a stellar black hole---the type that forms after stars die, collapse, and explode. Researchers had previously believed that the size limit was no more than 20 times the mass of our sun because 8S these stars die, they lose most of their mass through explosions that expel matter and gas swept away by stellar winds
This theory has now been toppled by LB-1, the newly discovered black hole. Located about 15.000 light years away, it has a mass 70 times greater than our sun, according to a press release from the Chinese Academy of Sciences.
The findings were published by Chinese researchers in the journal Nature on Wednesday.
"Black boles of such mass should not even exist in our galaxy, according to most of the current models of stellar evolution," said Liu Jifeng, head of the team that made the discovery. "LB-1 is twice as massive as what we thought possible. Now theorists will have to take up the challenge of explaining its formation."
Scientists are now scratching their heads at how LB-1 got so huge.
The Chinese team has proposed a number of theories. LB-1' sheer size suggests that it “was not formed from the collapse of only one star," the study said--- instead, it could potentially be two smaller black holes orbiting each other.
Another possibility is that it formed from “fallback supermova.” This is when a supernoma---the last stage of an exploding star---ejects material during the explosion, which then falls back into the supernova, creating a black hole.
This fallback formation is theoretically possible, but scientists have never been able to prove or observe it. If this is how LB-1 formed, then we may have "direct evidence for this process” for the first time, the study said.
There are several types of black holes and stellar black holes like LB-1 are on the smaller side, according to NASA. Supermassive black holes are much bigger---they can be billions of times the mass of our sun,
Scientists believe supermassive black holes may be connected to the formation of galaxies, as they often exist at the center of the mass star stems but it is still not clear exactly how, or which form first.
1.Why does the writer write the article?
A.To report the great achievement Chinese scientists have made in black hole theory,
B.To inform the readers of the basic knowledge about the black hole,
C.To share with the readers the new development of the black hole discovery,
D.To demonstrate the significance of discovering new black holes for science.
2.Which of the following about LB-1 is true to the passage?
A.It is the biggest black hole ever discovered,
B.It lost only a small part of its mass through explosion.
C.It couldn't have been formed from the collapse of one star,
D.Its discovery may lead to some breakthrough in the “fallback formation theory".
3.Which of the following is right according to the passage?
A.If the sun in our galaxy dies some of its mass will be taken away by stellar winds.
B.A massive supernova will be formed and then exploded if the sun in our galaxy dies.
C."The Milky Way" was formed after a supermassive black hole collapsed and exploded.
D.If “the Milky Way" dies, a supermassive black hole will be formed after its death.
It can be tough to pull kids away from their computers and mobile devices these days. While they're playing games, wouldn't it be great if they could be learning at the same time? Good educational apps offer fun challenges that teach specific grade-level skills. Here are 4 that combine fun and learning.
Understanding Math---Addition and Subtraction ($3.99; iOS)
Understanding Math---Addition and Subtraction goes beyond basic comprehension to instill a deeper understanding of the whys and hows of math. The app tracks your child's progress to determine strengths and weaknesses in different skill areas, and you can customize your child's learning experience to suit the needs.
Word Creativity Kit ($52.99; iOS)
Word Creativity Kit aims to make creative writing fun while also build up grammar rules. The app presents a series of words from seven categories, such as space or fantasy. Kids add their own words to finish the complete thoughts that these words have inspired.
Barefoot World Atlas ($4.99; iOS)
Barefoot World Atlas helps kids learn about geography and world cultures with a touch of the screen. Each region features a set of subtopics, from wildlife and natural features to native people, landmarks, and architecture. These facts and illustrations are delivered in photographs, sounds, and hundreds of mini videos.
My Grades & Homework (S0.99; iOS)
A combination of grades and homework tracker, My Grades & Homework can help your child stay organized and on top of the progress in school. A convenient calendar and course list format offer a glance at your child's assignment schedule that he/she might not normally get from standard homework planners.
1.What is the common part of the four apps?
A.They can encourage children to study harder.
B.They cam help parents know their children's progress.
C.They can make study fun by mini videos.
D.They can be installed into iOS operation systems
2.What is the purpose of the text?
A.To encourage parents to allow their students to play apps.
B.To wish readers to bring in more similar apps for children.
C.To introduce 4 educational apps for readers to buy and use.
D.To design the educational apps to combine fun and learning.
ProjectArt is an arts program providing free arts classes to children at public libraries in major US cities.
____ to the arts encourages children's self-worth, helps them communicate and improves their _________in academic areas. Yet, since the 1980s, access to arts education for American school children has been on the________
But where the American public school system is______ children, non-profits are ______ to fill the emptiness, and one organization in particular has __________ plans to become the largest free art school for children in the country.
ProjectArt, founded by AdarshAlphons in Harlem in 2011, is______to New Orleans and San Francisco, two cities with many homeless young people and giving the organisation a(n)_______ in a total of eight cities across the US.
Its executive director, Diana Buckley Muchmore _______with ProjectArt in its early days, and one experience impressed on her the_______that art can make on a child's development._______ her friend Alphons in teaching in a Harlem community center, Buckley Muchmore met a boy. "He was very quiet, but I _______ with him through a sculpture he was making_______wood, and he slowly started to_______to describe his work," she remembers.
Since then, Buckley Muchmore has watched as ProjectArt has embraced a model of_______with the country's public library systems. The libraries give them_______ space, access to existing communities and materials to _______ the children's creations.
In the meantime, the organization is working to serve the particular needs and take_______of the resources of its newest cities. In San Francisco, Buckley Muchmore has an eye on big companies like Airtbnb and Adobe, which she hopes to _______ for funding. The organization also receives_______ from foundations and individuals.
“In terms of less populated communities, we'll get there too," says Buckley Muchmore. "Eventually, we'll be in all the cities that have libraries."
1.A.Exposure B.Entrance C.Invitation D.Addiction
2.A.popularity B.expectation C.performance D.identity
3.A.decline B.account C.way D.rise
4.A.satisfying B.transforming C.supporting D.failing
5.A.letting of B.stepping in C.taking up D.falling out
6.A.great B.strange C.difficult D.secret
7.A.moving B.allocating C.returning D.expanding
8.A.evidence B.guidance C.presence D.reference
9.A.separated B.volunteered C.toyed D.conflicted
10.A.impact B.remark C.barrier D.progress
11.A.Appealing B.Including C.Joining D.Watching
12.A.dealt B.connected C.played D.compared
13.A.in between B.up to C.out of D.away from
14.A.hold out B.stand up C.figure out D.open up
15.A.partnering B.struggling C.exchanging D.consulting
16.A.parking B.green C.living D.free
17.A.respect B.inspire C.reward D.challenge
18.A.charge B.advantage C.notice D.control
19.A.arrange B.prepare C.trade D.approach
20.A.invitations B.appreciations C.donations D.congratulations
--- Do you know anything about War of Seven Kingdoms, the Chinese Game of Thrones?
---Sure. Although each event _____ a well-known actor playing the key roles, it has all its plots well _____on established historical records and archaeological findings.
A.features; grounded B.characteristics; witnessed
C.stars; depended D.displays; commented
I watched Mike's adolescence, _____ he ran into trouble, _____things at the wrong time and misunderstood by many people.
A.when; saying B.which; said C.when; said D.which; saying
China’s year-on-year growth in consumer price index ________ an almost eight-year high at 4.5 percent in November ________ higher prices of pork and other meat said the National Bureau of Statistics on Tuesday.
A.hit; but for B.beat; due to C.beat; but for D.hit; due to
