Technology

Updated at 4:35 p.m. ET

After the huge sell-off Wednesday, U.S. stocks fell sharply again Thursday. At one point, the Dow was down nearly 700 points. By late afternoon, it had regained some ground but closed down 546 points or a little more than 2 percent.

Over the past two days, the Dow has lost 1,378 points. The S&P 500 was down 2 percent for the day. The Nasdaq lost 1.25 percent.

Passwords that took seconds to guess, or were never changed from their factory settings. Cyber vulnerabilities that were known, but never fixed. Those are two common problems plaguing some of the Department of Defense's newest weapons systems, according to the Government Accountability Office.

The flaws are highlighted in a new GAO report, which found the Pentagon is "just beginning to grapple" with the scale of vulnerabilities in its weapons systems.

Google plans to shutter its Google+ social network for consumers, citing its limited adoption with users. The tech giant announced the decision at the same time that it disclosed that the privacy of up to a half-million Google+ accounts could have been affected by a "bug."

The company says it discovered and patched the issue in March but decided not to disclose it immediately. It said it had no evidence that any third-party developer was aware of the bug or had misused profile data.

New laws in Europe and California are forcing tech companies to protect users' privacy or risk big fines.

Now, the industry is fearing that more states will enact tough restrictions. So it's moving to craft federal legislation that would pre-empt state laws and might put the Federal Trade Commission in charge of enforcement.

Europe enacted a tough law in May which requires, among other things, that companies make data breaches public within 72 hours of discovering them.

Paige Thesing has struggled with insomnia since high school. "It takes me a really long time to fall asleep — about four hours," she says. For years, her mornings were groggy and involved a "lot of coffee."

After a year of trying sleep medication prescribed by her doctor, she turned to the internet for alternate solutions. About four months ago, she settled on a mobile phone meditation app called INSCAPE.

A year ago, Chinese President Xi Jinping stood before the 19th Communist Party Congress and laid out his ambitious plan for China to become a world leader by 2025 in advanced technologies such as robotics, biotechnology and artificial intelligence.

It was seen as a direct challenge to U.S. leadership in advanced technology. James Lewis, a specialist in China and technology at the Center for Strategic and International Studies, says China recognizes that technological superiority helps give the United States an edge in national security and wants in on it.

At the Vdara Hotel and Spa in Las Vegas, robots are at the front line of room service. "Jett" and "Fetch" are delivery robots, designed to look like dogs, each about three feet high.

They can bring items from the hotel's cafe right to your room. Among their many capabilities, they can travel alone across the lobby, remotely call for an elevator, and even alert guests when they arrive at their hotel room through an automated phone message.

This week in the Russia investigations: 21st century great power competition means the challenge of defending American democracy will get tougher, not easier.

The woods are dark and deep

Americans inside and outside of Washington, D.C., spent the last week transfixed by the drama over President Trump's nominee for the Supreme Court, but there also were ample reminders about how the rest of the world is not standing still.

The Department of Transportation has announced new federal voluntary guidance on the development and use of automated vehicles — with the goal of "removing unnecessary barriers" to innovation.

Last week, Facebook announced the most serious security breach in its history, in which unknown hackers were able to log onto the accounts of nearly 50 million Facebook users.

Updated at 2 p.m. ET

A federal grand jury in Pennsylvania has indicted seven Russian military intelligence officers, accusing them of hacking into U.S. and international anti-doping agencies and sports federations and of accessing data related to 250 athletes from about 30 countries.

Most of the Twitter accounts that spread disinformation during the 2016 presidential campaign remain active now, according to an ambitious new study released on Thursday.

Knight Foundation researchers examined millions of tweets and concluded that more than 80 percent of the accounts associated with the 2016 disinformation campaign are still posting — even after Twitter announced back in July that it had instituted a purge of fake accounts.

Capitol Police have arrested a man accused of publishing to the Internet restricted personal information about South Carolina Republican Sen. Lindsey Graham.

Travelers arriving in New Zealand may be asked to enter their passcode or fingerprint to allow customs agents to search their electronic devices. And if they don't comply? They could be fined up to 5,000 New Zealand dollars — about $3,270 U.S.

This is due to new legislation called the Customs and Excise Act 2018, which updates language from a 1996 law. The law, which went into effect this week, also gives agents the authority to copy or clone any data on searched devices.

The Mascot lander floated down to the surface of an asteroid hurtling through space, capturing photographs and other data, according to the German Aerospace Center. The lander sent a photo of its descent — showing its own shadow on the asteroid's surface.

The craft's Twitter feed echoed Alice in Wonderland, declaring: "And then I found myself in a place like no place on Earth. A land full of wonder, mystery and danger!"

Updated on Wednesday at 4:15 p.m. ET

Wednesday afternoon, at exactly 2:18 p.m. ET, million of Americans received a text headlined "Presidential Alert" on their cellphones.

But it wasn't exactly from President Trump. Rather, it was a test of a new nationwide warning system that a president could use in case of an armed attack by another country, a cyberattack or a widespread natural disaster.

Astrophysicist Neil deGrasse Tyson is an expert on just about everything.

India has 1.3 billion people, and no equivalent of the Social Security number. About 4 in 10 births go unregistered. Less than 2 percent of the population pays income tax.

Many more are eligible for welfare benefits but may never have collected them, either because they can't figure out how or a middleman stole their share.