Tech mogul Elon Musk -- known as widely for slinging cars into the sun's orbit as he is for advocating against COVID-19 safety measures -- took to Twitter Thursday to slam Facebook over its latest privacy policy updates for its supposedly secure encrypted messaging app WhatsApp. Musk instead recommended users choose encrypted messaging app Signal.

The tweet was then retweeted by Twitter CEO Jack Dorsey. Shortly after, Signal tweeted that it was working to handle the surge of new users.

This isn't the first time Musk has publicly sparred with Facebook over privacy concerns. In 2018, he not only had his own personal Facebook page removed, but that of his companies Tesla and SpaceX. His take on the long-fought battle between Signal and WhatsApp isn't off-base, though.

Both of the encrypted messaging apps have been found to have security bugs over the years that have been resolved. For years, WhatsApp has openly collected certain user data to share with parent company Facebook. Its latest policy change just expands that. Signal, on the other hand, has a history of fighting any entity that asks for your data, and adds features to further anonymize you where possible.

Here are the basics of Signal you should know if you're interested in using the secure messaging app.

What Signal is, and how encrypted messaging works
Signal is a typical one-tap install app that can be found in your normal marketplaces like Google's Play Store and Apple's App Store, and works just like the usual text messaging app. It's an open source development provided free of charge by the non-profit Signal Foundation, and has been famously used for years by high-profile privacy icons like Edward Snowden.

Signal's main function is that it can send text, video, audio and picture messages protected by end-to-end encryption, after verifying your phone number and letting you independently verify other Signal users' identity. You can also use it to make voice and video calls, either one-to-one or with a group. For a deeper dive into the potential pitfalls and limitations of encrypted messaging apps, CNET's Laura Hautala's explainer is a life-saver. But for our purposes, the key to Signal is encryption.

Despite the buzz around the term, end-to-end encryption is simple: Unlike normal SMS messaging apps, it garbles up your messages before sending them, and only ungarbles them for the verified recipient. This prevents law enforcement, your mobile carrier and other snooping entities from being able to read the contents of your messages even when they intercept them (which happens more often than you might think).

When it comes to privacy it's hard to beat Signal's offer. It doesn't store your user data. And beyond its encryption prowess, it gives you extended, onscreen privacy options, including app-specific locks, blank notification pop-ups, face-blurring anti-surveillance tools, and disappearing messages. Occasional bugs have proven that the tech is far from bulletproof, of course, but the overall arc of Signal's reputation and results have kept it at the top of every privacy-savvy person's list of identity protection tools.

For years, the core privacy challenge for Signal lay not in its technology but in its wider adoption. Sending an encrypted Signal message is great, but if your recipient isn't using Signal, then your privacy may be nil. Think of it like the herd immunity created by vaccines, but for your messaging privacy.

Now that Musk and Dorsey's endorsements have sent a surge of users to get a privacy booster shot, however, that challenge may be a thing of the past.

Elon Musk displaces Jeff Bezos as richest person on Earth
The Tesla and SpaceX founder has a net worth of $188.5 billion.

Elon Musk has overtaken Jeff Bezos as the richest person in the world, Bloomberg reported Thursday.

Musk, who founded electric car manufacturer Tesla and rocket maker SpaceX, has a net worth of $188.5 billion, which clocks in at about $1.5 billion more than Amazon's Bezos, Bloomberg said, attributing the shift to an increase in the price of Tesla shares.

On Twitter, Musk responded to a tweet about his new standing with two tweets saying "How strange" and "Well, back to work ..."

Musk's been climbing the rankings. In November, he unseated Bill Gates as the second richest person when his net worth hit $128 billion.

Although Bezos hasn't consistently held onto the title, he claimed the top spot in October 2018 (it also happened briefly in 2017) when his net worth hit $160 billion. Gates had previously held the spot for 24 years.

Neither Musk nor Bezos responded to a request for comment.

Elon Musk reveals wild plan to catch SpaceX rocket with a launch tower
The super powerful Super Heavy could launch one Starship and return to Earth to launch another one as soon as an hour later.

One day in the not-too-distant future, Elon Musk envisions blasting off from Earth and sending his next-generation Starship on its way to the moon, Mars or just the other side of the world. Several minutes later, the first-stage booster used for liftoff makes its way back to the launch tower, where it's "caught" by a specially designed arm and readied for another launch in as soon as an hour.

The SpaceX chief hinted at the plan in a series of tweets Wednesday.

We’re going to try to catch the Super Heavy Booster with the launch tower arm, using the grid fins to take the load

— Elon Musk (@elonmusk) December 30, 2020
"We're going to try to catch the Super Heavy Booster with the launch tower arm, using the grid fins to take the load," he wrote in response to another Twitter user.

Super Heavy is the next-generation booster designed to be paired with the SpaceX Starship now under development at the company's facility in Texas. You may have seen the first successful high-altitude test flight of an early Starship prototype earlier this month, which ended with a big bang of a hard landing.

Musk's vision is that Starship will eventually carry up to 100 passengers out into the solar system and on super quick transcontinental flights via space.

The current SpaceX workhorse rocket, the Falcon 9 used to launch satellites and missions to the International Space Station, returns to Earth and lands using retractable landing legs. For Super Heavy, which will rival the largest and most powerful rockets ever built, Musk sees advantages in eliminating those legs.

"Saves mass & cost of legs & enables immediate repositioning of booster on to launch mount -- ready to refly in under an hour," he tweeted.

The move redirects the stress of a landing onto the grid fins, which are located near the top of the booster and are essentially used to steer the rocket during flight, and onto some sort of apparatus on the launch tower that the grid fins will come to rest on.

Musk said using legs to land Super Heavy is still an option as well.

"Legs would certainly work, but best part is no part, best step is no step," he wrote.

When we will see all of this in action isn't clear. SpaceX is working on Super Heavy in Texas, but expect several more test flights of solo Starship prototypes without the big booster before we see any of these possible innovations in real life.

Trump's impeachment process may start Monday. Here's what you should know
More than 200 members of Congress are calling to remove Donald Trump from office in the final days of his presidency. We look at what the process is, how it would take place, and what would result.

More than 200 members of Congress are calling to remove President Donald Trump from office, either through impeachment or the 25th Amendment, with House Democrats planning to introduce the articles of impeachment Monday according to multiple reports. One impeachment article is "incitement of insurrection."

The rally to impeach Trump condemns a violent insurrection of the US Capitol, when a mob breached the building while seeking to overturn the 2020 presidential election results. Trump is widely accused of inciting the crowd to riot for the purpose of interfering with a democratic proceeding. The DOJ does not plan to level incitement charges against Trump or any other speakers at the rally, according to a tweet from an anchor with MSNBC.

If successful, the action would remove Trump from power in his final days as president before the inauguration of President-elect Joe Biden on Jan. 20, as well as possibly curtail some of his privileges as former president. If the articles of impeachment are initiated, it would mark the second time in his presidency that Trump would face the process -- and would make him the first president in history to be impeached twice.

By Friday morning, some forecast that an impeachment vote in the House of Representatives could come by the middle of next week.

As the situation in Washington develops, we'll explain the scope and limitations of impeachment, what the timeline would be before Biden is sworn in as president, and where the situation stands now.

Is it too late to impeach Trump before Biden takes office?
Impeachment can be a long process, but if passed by both chambers in Congress, the effects could be long-lasting. Not only would Trump be removed from the presidency, he would also be disqualified from running for a second presidential term, or "any Office of honor, Trust or Profit under the United States," according to the Constitution (Article 1, Section 3).

If the Senate and House both agreed to impeach Trump, he would also be disqualified from the benefits given to former presidents in the Post Presidents Act, including a pension and security detail.

When Trump was impeached in December 2019, the entire process took months -- from inquiries and investigations beginning in September 2019 to the Senate acquitting him on Feb. 6, 2020. Given the traditionally slow process, it could take too long to impeach Trump and remove him from office prior to the inauguration of Biden on Jan. 20.

It isn't clear if impeachment proceedings would continue after Biden's inauguration, or if Washington, DC or other states would take their own legal action. Biden has made it clear he wants Trump out of office by being sworn into the presidency himself, but ultimately said it was up to Congress to decide.

Read more: Facebook blocks Trump indefinitely following Capitol Hill violence

Rep. Jerry Nadler, a Democrat from New York and chair of the House Committee on the Judiciary, said he supports "bringing articles of impeachment directly to the House floor."

"I am once again urging that the President be impeached and removed from office," Nadler tweeted Thursday evening. "We have a limited period of time in which to act. The nation cannot afford a lengthy, drawn out process."

Despite support from some Republican Congress members, the Senate is currently still a Republican majority. Newly elected Georgian Democratic Senators Jon Ossoff and Raphael Warnock have yet to be sworn in -- as has Vice President-elect Kamala Harris, who would serve as a tiebreaker if the matter came to that. While Harris will be sworn in as vice president on Jan. 20, Georgia has yet to certify its results, and Congress has already convened without Warnock and Ossoff.

What does it take to impeach a sitting president?
A president, along with other officers, can be impeached for "treason, bribery, or other high crimes and misdemeanors," according to Section 4 of Article 2 of the US Constitution.

To impeach, a total of 216 votes are required from the House of Representatives -- a simple majority plus one. A trial is then heard in the Senate, where the US Chief Justice presides. A full two-thirds of the 100 senators must vote to impeach.

If the Senate were to convict Trump, it would not only remove him from the White House as soon as the vote occurred -- it would also prevent him from ever being able to run for a second presidential term.

The White House criticized the move towards impeachment, saying it should be "a time for healing and unity" in a statement Friday. "A politically motivated impeachment against a president with 12 days remaining in his term will only serve to further divide our great country," the White House said.

What's the difference between impeachment and the 25th Amendment?
Congress -- including Republican representatives -- have also been pushing Vice President Mike Pence to invoke the 25th Amendment of the US Constitution to remove Trump from office. Unlike impeachment, which is voted by Congress, the 25th Amendment would require Pence and a majority of the sitting Cabinet secretaries to invoke the power. Alternatively, it could also be invoked by the Vice President and another body that's designated by Congress.

In order to do so, Pence and a majority of sitting Cabinet secretaries must decide a sitting president is unfit for office. Several cabinet members have now resigned.

Pence has reportedly said he will not invoke the 25th Amendment.

"The President of the United States incited an armed insurrection against America," House Speaker Nancy Pelosi said in a press conference Thursday. "In calling for this seditious act, the president has committed an unspeakable assault on our nation and our people. I join the Senate Democratic leader in calling on the Vice President to remove this president by immediately invoking the 25th Amendment."

Read more: 25th Amendment: What it is, how it would remove Trump from power if invoked

Congress certified Biden and Vice President-elect Kamala Harris' victory in the 2020 election in the early hours of Thursday after reconvening Wednesday night following their evacuation from the Capitol. Trump later appeared to grudgingly agree to an "orderly transition" of power.

In a video released Thursday evening, Trump reiterated that he's now working on the transition. "A new administration will be inaugurated on Jan. 20th," Trump said. My focus now turns to ensuring a smooth, orderly, and seamless transition of power."

Why Democrats are pushing impeachment
Pelosi summed up her party's position: "The President's dangerous and seditious acts necessitate his immediate removal from office," she said Thursday.

Minnesota Democratic Rep. Ilhan Omar tweeted Wednesday afternoon that she was drawing up articles of impeachment, while under evacuation of Congress during the insurrection. "Donald J. Trump should be impeached by the House of Representatives & removed from office by the United States Senate," Omar tweeted at the time. "We can't allow him to remain in office, it's a matter of preserving our Republic."

By 7:30 p.m. ET Wednesday, more than 20 Democratic members of Congress had joined calls for Trump's impeachment.

Articles of Impeachment for introduction, so proud of everyone co-leading this effort with us.

We need to move quickly to remove this President from office. pic.twitter.com/vbZtA7g6fc

— Ilhan Omar (@IlhanMN) January 7, 2021
Omar tweeted out the Articles of Impeachment being circulated by the House Democrats just after noon ET Thursday. She is sponsoring the resolution to remove Trump from office, with co-leads Alexandria Ocasio-Cortez, Cori Bush, Mondaire Jones, Rashida Tlaib, Ayanna Pressley, Veronica Escobar, Jamal Bowman, Ted Lieu, Hank Johnson, Al Green and David Cicilline.

In urging Pence to invoke the 25th Amendment, Pelosi said Congress may otherwise move forward with impeachment.

Calling Trump "a complete tool of Putin," Pelosi said it would be "very dangerous" to allow him to continue in office until the inauguration. "While it's only 13 days left, any day can be a horror show for America," she said.

The impeachment had over 150 co-sponsors as of Friday afternoon. Omar tweeted to thank "the hundreds of members" who heard the calls of Americans to impeach.

The House Democrats are meeting Friday afternoon to discuss impeachment. "Our House Dem Caucus is meeting RIGHT NOW to discuss 25th Amendment, Impeachment, and other immediate actions," Rep. Jared Huffman tweeted Friday at 3 p.m. ET. "This is an emergency and we are not waiting to act."

Following the Friday meeting, Pelosi said that if Trump does not immediately resign, the Rules Committee has been instructed to move forward with 25th Amendment legislation and a motion for impeachment. "The House will preserve every option -- including the 25th Amendment, a motion to impeach or a privileged resolution for impeachment," she said in a statement.

Rep. Omar said waiting for Monday would be "too late," tweeting Friday evening "The nation is waiting for us to respond ASAP."

Some Republicans also urge impeachment
Multiple GOP leaders echoed the calls for impeachment, or for Vice President Mike Pence and the Cabinet to invoke the 25th Amendment of the Constitution to remove Trump from power.

In a video on Twitter during the early hours of the insurrection, Wisconsin Republican Rep. Mike Gallagher likened the insurrection to actions seen in so-called "banana republics." Sen. Mitt Romney, a Republican from Utah, took to the chamber floor in later hours to decry Trump's encouragement of the mob.

House Republican Conference Chair Liz Cheney accused the president of "abusing the trust of the people who supported him" while GOP Rep. Adam Kinzinger of Illinois and Sen. Tom Cotton of Arkansas demanded Trump acknowledge his election loss. Former President George W. Bush, the last living Republican president, released a statement calling the violence "sickening."

However, it’s difficult to see the president’s most blind and loyal supporters ever rising to this most pressing occasion. Therefore, I join my colleagues in the House in submitting articles of impeachment for President Trump’s high crimes & misdemeanors against our nation.

— Rep. Linda Sánchez (@RepLindaSanchez) January 7, 2021
Republican Sen. Ben Sasse told CBS News Friday that he would "definitely consider" the impeachment articles if the House votes to impeach.

GOP Sen. Lisa Murkowski has even called for Trump to resign as president immediately. "I want him to resign. I want him out. He has caused enough damage," Murkowski told the Anchorage Daily News late Friday. "If the Republican Party has become nothing more than the party of Trump, I sincerely question whether this is the party for me."

Wasn't Trump impeached once already?
Yes. Trump was previously impeached in December 2019 by the House. However, the Republican-majority Senate acquitted him at the beginning of 2020 -- with the process marked by a record number of tweets from Trump disparaging the impeachment trial.

His previous impeachment involved two articles accusing Trump of abusing power and obstructing Congress. On that occasion, the issue was Trump's dealings with Ukraine, including a phone call in July 2019 during which he appeared to ask that country to investigate ties between Joe Biden, his son Hunter Biden and a Ukrainian gas company.

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