Sen. Ted Cruz (R-Texas) might want to watch out; there's a new punk rocker in town.

Rep. Beto O'Rourke (D-Texas) reportedly plans to declare Friday that he is running for Cruz's Senate seat in 2018, people familiar with the decision have told The Houston Chronicle. Described by the paper as a pro-marijuana term-limit-supporting liberal who "played in three punk rock bands during and after his college years at Columbia University," O'Rourke, 44, said he was "very moved" to run for Senate in an interview earlier this month.

While Cruz failed in his bid for the presidency last year, he still has a wealth of fundraising sources across the nation and O'Rourke would face an uphill battle against him in the perennial red state. But "Beto brings a fresh approach, a new face, and is someone who is able to connect with Texans across the board," said Matt Angle, the executive director of the Lone Star Project, which promotes Democrats in Texas.

Additionally, because Cruz, as a conservative leader, is a juicy target for liberal groups, O'Rourke could also potentially attract the attention of the senator's out-of-state opponents — and their money.

May the best punk rocker win. Jeva Lange

Game of Thrones just went out on top by breaking another viewership record.

The series' final episode, "The Iron Throne," drew 19.3 million viewers on Sunday, The Hollywood Reporter writes. This includes 13.6 million people who tuned into the initial 9:00 p.m. airing, as well as those who tuned in for replays and those who streamed the episode online.

This breaks Game of Thrones' previous ratings record — 18.4 million people tuned in last Sunday night to the season's fifth episode, "The Bells." It also sets a new record for HBO itself. The season 4 premiere of The Sopranos previously held the HBO record for biggest linear audience with 13.4 million viewers in 2002, although this was before the rise of streaming.

These impressive viewership numbers Game of Thrones has been drawing each week don't factor in those who watch the episode beyond Sunday night. When including those who watch later, HBO says the eighth season has been averaging 44.2 million viewers, Deadline reports.

Now, the network can only hope to retain these tens of millions of viewers for the forthcoming Game of Thrones spinoffs and that fans' watch hasn't ended quite yet. Brendan Morrow

Of the many mysteries of the beloved former planet Pluto, the likely presence of a liquid ocean under its icy surface is one of the biggest. Now, a new study is offering up a theory on how its ocean has avoided freezing along with the rest of the dwarf planet.

The new research, published on Monday in Nature Geoscience, used data from NASA's New Horizon spacecraft, which collected data from Pluto and its moon Charon back in 2015. That data, combined with computer simulations, determined that Pluto's ocean is probably insulated from the well-below-freezing temperatures of its surface and atmosphere by a layer of gas, CNN reported.

Methane, which would likely be released from Pluto's core back while it was still forming, "would be thick and have low thermal conductivity," which would allow it to act as an insulator between the large amounts of ice on the dwarf planet's surface and the liquid water underneath.

It's possible that similar insulating layers of gas exist elsewhere in our galaxy and beyond, hiding similar oceans from the extreme cold of outer space. This would make "the existence of extraterrestrial life more plausible," said Shunichi Kamata, the study's lead author. Read more at CNN. Shivani Ishwar

Rep. Justin Amash (R-Mich.) is back with another scorching Twitter thread.

On Saturday, Amash, a common critic of Trump, became the first sitting Republican congressmember to call for the president's impeachment. His GOP colleagues predictably had a big problem with that, but Amash still spelled out why he thinks Trump's impeachment defenders "are resting their argument on several falsehoods" in a series of Monday tweets.

According to Amash's reasoning, Trump's defenders "say there were no underlying crimes," "say obstruction of justice requires an underlying crime," claim Trump should be able to end a "frivolous investigation," and attempt to redefine "high crimes and misdemeanors." But there were "many" crimes — not that obstruction of justice charges require them, Amash continues in his thread. The "high crimes and misdemeanors" portion of impeachment proceedings aren't even "defined in the constitution," Amash also said, adding that a president just has to commit "conduct that violates the public trust."

Amash's Saturday tweetstorm has already led Michigan state Rep. Jim Lower (R) to announce he'll primary Amash next year. House Minority Leader Kevin McCarthy (R-Calif.) told Fox News that Amash "just want to have attention," though as CNN's Haley Byrd said in a tweet, that doesn't usually seem to be Amash's top priority. Kathryn Krawczyk

The Game of Thrones finale might have been highly controversial among fans, but the show's leads are defending it as a fitting conclusion.

Several cast members have begun to weigh in with post-finale interviews, including Emilia Clarke, who spoke with Entertainment Weekly and called Daenerys' final scene "beautiful and touching." While admitting she initially had a difficult time processing her character's fate, she ultimately concluded that it was the "logical" outcome.

In an interview with The New Yorker, Clarke also defended the finale as "the only way it could end," adding she's "not sure it could" have gone differently for Daenerys.

Kit Harington similarly defended Daenerys' ending, telling Entertainment Weekly "this has been building" for many seasons and that there's "nothing done in this show that isn't truthful to the characters." While he didn't comment on Jon Snow's own conclusion, Harington previously said he was "maybe not happy, but very satisfied" with how things wrapped up.

Recently, comments from Clarke, Harington, and other Thrones stars appearing to express negative feelings about season eight have gained traction online, with one such compilation racking up nearly 12 million YouTube views. But based on these new quotes, it's clear those clips don't exactly paint the full picture, showing Clarke appearing to laugh nervously while attempting to not give away whether her character has a happy ending and Harington being sarcastic when he calls the ending "disappointing" before clarifying he actually thought it was "epic."

Isaac Hempstead-Wright also wrote in a Monday essay that he was thrilled with the finale, which he argued is fitting because "life doesn’t have neat, happy endings," while Sophie Turner similarly praised it and slammed the fan petition to remake the season as "disrespectful."

While expressing their own approval, prior to the finale airing, a number of stars did predict it would be divisive, which turned out to be even more accurate than they might have had in mind. Brendan Morrow

Artificial intelligence is officially joining the fight against cancer.

Google on Monday announced new research in training an AI tool to recognize the signs of lung cancer from a CT scan of a patient's chest. The research, which began in late 2017, has culminated in an AI capable of diagnosing lung cancer with better accuracy than certified radiologists.

In order to test the AI, Google showed it 45,856 chest CT scans, comparing the AI's diagnoses with those of six board-certified radiologists, Engadget reported. Google's AI was able to detect cancer in 5 percent more of these screenings than the radiologists; it also reduced false diagnoses by "more than 11 percent."

Radiologists typically have to view up to hundreds of images from a single CT scan in order to make a successful diagnosis for lung cancer; Google's AI is able to generate a three-dimensional image instead of 2-D ones, as well as detecting specific areas of malignant tissue in the lungs, which radiologists are often unable to do from images alone.

This AI modeling technique represents a breakthrough in the ability to diagnose cancers early on. Lung cancer, which accounts for more than 1.7 million deaths every year around the world, is often not caught until later stages, when treatment has a much lower chance of success. Google's technology will have to undergo further research and testing before becoming available as a diagnosis tool, but the company hopes to "make early detection more accessible." Shivani Ishwar

President Trump's trade war with China is about to go global.

Trump has spent pretty much his entire presidency trying to negotiate a trade deal with China, with both countries levying tit-for-tat tariffs all the while. And while those tariffs have mainly hurt American farmers so far, a new Morgan Stanley analysis published by Reuters suggests they could turn into a problem for the whole world.

After a brief hibernation, trade talks with China started up again earlier this month. And in the middle of those discussions, Trump upped a 10 percent tariff on $200 billion worth of Chinese exports to 25 percent, leading China to, of course, retaliate. If that pattern continues, specifically "if talks stall, no deal is agreed upon, and the U.S. imposes 25 percent tariffs on the remaining circa $300 billion of imports from China," then "we see the global economy heading towards recession," a Morgan Stanley analyst wrote in a Monday memo. The Federal Reserve Board would then have to cut interest rates down to zero, the analyst predicted.

Back in the states, the Peterson Institute for International Economics estimates Trump's current tariffs translate to an average tax hike of $550 for each American family, Politico reports. Extending that tariff to $500 billion worth of goods could lead to a $2,200 tax spike for a family of three. That effectively erases the $800 average tax cut U.S. families saw under Trump's Tax Cuts & Jobs Act. Making matters even worse, companies including Walmart are warning that ongoing tariffs will just lead to higher consumer prices. Read more about the everyday negatives of Trump's tariffs at Politico. Kathryn Krawczyk