July 20, 2021 marks the 52th anniversary of the first moon landing. The National Space Center will provide you with super-size space experiences: a giant Earth model, a domed planetarium （穹顶天文台） and a 42-meter rocket tower. It's all under cover so it's a good place to visit on a rainy day.

Ticket

It's not cheap-adult $15, 5-to-16-year-olds $12-but once you've paid you can revisitas many times as you want in a year, and admission is free for kids under five.

Opening hours

10 am-4 pm Monday to Friday, 10 am-5 pm weekends and school holidays.

What about lunch?

The Boosters Cafe serves reasonably priced hot and cold snacks and drinks at the foot of the center's two rockets. The cafe offers vegetarian (素食的)option too.

Exit through the gift shop?

It's stocked with souvenirs including books, games and telescopes. Some are quite pricey. The gift shop is the first thing you pass on entry and also the last thing you see as you leave.

The number of British students going to US universities has been climbing steadily over the past decade. The latest available figures (from 2017- 2018) show 11,460 British students are choosing to study in US. This represents a small drop (0.3%) from the previous year, showing that American degrees remain a popular choice.

Among the most popular American universities for British students are, Harvard, Y ale, Princeton, Stanford and also institutions with convenient location-- New York University in New York City, or the University of Southern California in Los Angeles, for example.

Two factors motivate young people to head west for universities: academic opportunity and the increasing availability of financial aid for foreign students. Anthony Nemecek, an education expert, explains, “While there are many reasons British students consider higher education study in the US, the main reason is the wide range of choice on offer, both subjects and institutions, as well as not having to decide their *major/course' until the end of the second year."

One reason why the Brits may be unwilling to pursue a US degree is the cost. The University of Oxford, for example, estimates living costs of f14,850 in 2020, along with course fees of f9,250, so a total of f24,100. The Massachusetts Institute of Technology (MIT), a world-leading specialist in science, costs $73,1 60 (£59,447; more than twice as much as Oxford), but most students at MIT will get financial aid. MIT is home to a financial aid program for international students, making it a great place to apply if money is not enough.

On a cold November morning in Y osemite National Park, on the south-west face of EL Capitan, Alex Honnold holds on to the side of the wall with nothing but the tips of his fingers and two thin edges of shoes, attempting to do something that professionals have long wanted to do--a“free solo” climb of the world's most terrifying cliff (悬崖). That means he is alone and climbing without a rope as he makes his way up more than half a mile of rock.

Paul Preuss, the father of the free soloing, stated the key of the climbing was to master a mountain with superior physical and mental skill, not “artificial aid". Having made some 150 ropeless climbs by the age of 27, he fell to his death in 1913 while free soloing in the Austrian Alps. But Preuss's ideas survived and inspired the “free climbing”movement of the 1960s, which supported using ropes and other safety equipment. The next free soloist appeared in 1973, when Henry Barber climbed up the 1,00--feet north face of Yosemite's Sentinel Rock without a rope. In 1976, John Bachar free soloed New Dimensions, a 300-foot cliff in Yosemite and Peter Croft free soloed two of Yosemite's most celebrated routes--- Astroman and Rostrum--in the same day.

Croft's achievement stood until 2007, when Honnold, then 22, astonished the world by repeating Croft's Astroman--Rostrum masterpiece and free soloed two famously tough routes in Zion National Park and Y osemite. Now, Honnold is attempting much higher goals and he is well on his way to completing the greatest rock climb in history.

Micro-plastics have occupied almost every part of the planet today, including the most distant reaches.

The Arctic is far from clean, though it s rarely stepped in by visitors. Melanie Bergmann, a marine ecologist (海洋生态学家) and her colleagues had been studying plastics on the Arctic seafloor since 2002. In deep sea, they found about 6,0000 particles (微粒) in every 2.2 pounds of mud. In sea ice, there were as much as 12,000 pieces per 34 ounces of melted ice.

Scientists measured micro-plastics in snow from this distant location and found a lot, which could only have caught rides on the wind. The study raises concerns about the pollution that micro-plastics brought to the air, bringing a health risk to people and animals that breathe them in. But they are less worried about the threat that breathed-in pollutants have to wildlife than about polluted snow going into water.

The science on the health effects of micro-plastics is still going on.“For human health, we now now very little," says micro-plastics researcher Chelsea Rochman, “There is a lot of concern. For wildlife, we know that micro-plastics may go into every level of the food chain." Laboratory studies find some physical and chemical effects from micro-plastics, but the findings vary by the plastic type, shape experiments will be carried out soon with use of equipment if financial support approves."

Even worse is the threat from airborne micro-plastics in the area---too small to be noticed and may actually enter cells. Research on that also has been done and it could be a bigger problem, according to Rochman.