Low-grade methane leaks are bad for business (that gas could be heating up a home) and bad for the environment (it traps heat up in the atmosphere). Because a methane spill is invisible and has no smell — unless there's about to be an explosion (and if so, run!) — it can be hard to track one down.

That's where a tricked-out Google Street View car comes into play. Google Earth Outreach and the Environmental Defense Fund have teamed up to turn several Subaru Imprezas into mobile methane trackers. As Bloomberg reports, scientists add tubing across the front grill, which helps push a constant stream through a very small dehumidifier and then into a gas analyzer. Real-time data is streamed to a monitor, showing how fast the car is driving and the amount of methane on the street.

The pilot project's results were released on Wednesday, with information coming in from Boston, Indianapolis, and Staten Island. The findings seem to show that older cities have more of an issue with leaks, likely due to old infrastructures. Indianapolis, which has newer pipes, was the cleanest, with just one leak recorded for every 200 miles.

Those involved in the project are excited to use the information as a way of influencing how cities plan in the future. "This is the beginning of what I really see as a big shift in the way we can give people data about the environments they live in," Steven Hamburg, chief scientist for the EDF, told Bloomberg.

For in-depth maps of methane leaks in the three areas, visit the Environmental Defense Fund website. Catherine Garcia

The highly anticipated fight between undefeated boxing world champion Floyd Mayweather Jr. and the current UFC lightweight champion, Conor McGregor, could hit a snag if McGregor doesn't lose 10 pounds by Saturday, Mayweather warned FightHype.com on Tuesday. The limit for the light middleweight class is 154 pounds.

"Conor McGregor is extremely heavy right now, extremely heavy," Mayweather said. "I think he's like 164. So he's still got 10 pounds to go." It's unclear whether Mayweather knows definitively that McGregor is overweight or is just adding fuel to the publicity fire.

Mayweather added that McGregor "better get them extra millions ready or somebody's going to pay a fine. You gotta get that weight down. A true champion is disciplined and very responsible." He said that if McGregor didn't make weight, there'd still be a fight, "but it's going to be a heavy fine. Give me that money." Jeva Lange

George and Amal Clooney's Clooney Foundation for Justice has donated $1 million to fight hate groups in the U.S. after violent protests in Charlottesville, Virginia, earlier this month, the Los Angeles Times reports. The Clooneys joined forces with the Southern Poverty Law Center to "increase the capacity of the SPLC to combat hate groups in the United States."

"Amal and I wanted to add our voice (and financial assistance) to the ongoing fight for equality," said actor George Clooney in a statement. "There are no two sides to bigotry and hate." The couple added: "What happened in Charlottesville, and what is happening in communities across our country, demands our collective engagement to stand up to hate."

The SPLC follows more than 1,600 extremist groups across the country, including the neo-Nazi, white nationalist, and neo-Confederate groups that rallied in Charlottesville. Jeva Lange

President Trump is holding a campaign-style rally in Phoenix, Arizona, on Tuesday night, where he is expected to focus on immigration, border security, and national unity. Trump will meet with border patrol officers ahead of the event and could possibly visit the border as well, The New York Times reports.

The rally comes amid a push within the White House for Trump to "strike an ambitious deal with Congress that offers [children of immigrants shielded by the DREAM Act] protection in exchange for legislation that pays for a border wall and more detention facilities, curbs legal immigration, and implements E-verify, an online system that allows businesses to check immigration status," McClatchy writes.

Phoenix Mayor Greg Stanton (D) asked Trump last week to postpone the rally, especially if he plans to pardon Joe Arpaio, the former Maricopa County sheriff recently convicted of criminal contempt after he disregarded a federal judge's order to stop arresting immigrants based solely on the suspicion that they had entered the country illegally. Jeva Lange

No one can quite figure out why the family of Housing and Urban Development Secretary Ben Carson keeps hanging out around HUD, New York and ProPublica report. Carson's wife, Candy, has "been spending far more time inside the department's headquarters at L'Enfant Plaza than anyone could recall a secretary's spouse doing in the past," with Candy confusing things even more when she slipped an awkward "we" into a speech about the work Carson's department would be doing.

In addition to "the omnipresent Mrs. Carson," there are also the unexpected contributions of Carson's second-oldest son:

Ben Carson Jr., who goes by B.J. and co-founded an investment firm in Columbia, Maryland, that specializes in infrastructure, health care, and workforce development, was showing up on email chains within the department and appearing often at headquarters. One day, he was seen leaving the tenth-floor office of David Eagles, the new COO, who was crafting a HUD reorganization to accompany the cuts. [New York/ProPublica]

When asked about his "active role," Ben Jr. told reporter Alec MacGillis, "With anything where we can be helpful, if Dad asks us to come along and help out, we'll always do that. We're here to offer support, whatever we can do." When pressed, Ben Jr. added puzzlingly: "If you're a concerned citizen and you're not spending time in D.C. trying to actually make sure the right things are happening, then you probably could do more. You should have access to your public officials, and if that's not allowed, then there's a big problem with how the representatives are handling their relationship with citizens." Read the full report at New York. Jeva Lange

If you're a politician looking to build up your social media following, your best bet is to avoid the political center. That's the conclusion of a new analysis by Pew Research Center, which found that the closer a lawmaker is to the ideological extremes, the larger their social media presence tends to be.

(Pew)

The disparity was stark. In the House, the representatives furthest to the left and right "had a median of 14,361 followers as of July 25, compared with 9,017 followers for those in the middle of the ideological spectrum," Pew reports. In the Senate, the more ideological lawmakers had a median following of 78,360. Centrists had just 32,626.

Beyond general polarization, Pew attributes its findings at least in part to a tendency among the politicians at the edges of the political spectrum to share more inflammatory — and thus more engaging — content. Lawmakers with a clear philosophical stance also tend to get more media exposure, Pew notes. Bonnie Kristian

Trump campaign surrogate Katrina Pierson decided to defend retaining Confederate monuments in positions of public honor during a Fox & Friends segment Monday morning by arguing the history of slavery and the Civil War is "good history" that shows "how special and wonderful this country is."

Pierson was speaking with Fox host Ainsley Earhardt opposite Wendy Osefo, a Johns Hopkins University professor and Democratic strategist. Osefo argued the statues represent a "nefarious" part of U.S. history, a part that "doesn't deserve a place on state grounds; it deserves a place in museums." Pierson disagreed, and the result was this remarkable exchange (which has been edited lightly for clarity amid furious crosstalk):

"It absolutely deserves a place," Pierson interjected, "because bad history is still good history for this country."

"Slavery is good history?" Osefo asked in shock.

"Absolutely," Pierson responded. "Where would we be today if not for that Civil War? How would people know how special and wonderful this country is?" [Mediaite]

Pierson appeared to be arguing that slavery and the Civil War was a character-building experience for the United States, and that the country's founders were laudable for being "slave owners who actually put in a place to change the laws." The segment rapidly descended into chaos as Osefo demanded to know whether Pierson realizes that hundreds of thousands of people suffered and died in this "good history."

Pierson's father is African-American, a fact she has used in service of her support for President Trump. "A racist does not pick a single black mother to represent his entire freaking presidential campaign," Pierson said in reference to herself and Trump in a New York Times article last week.

Watch the Fox conversation below. Bonnie Kristian

The New York Times' conservative op-ed columnist Bret Stephens ruled Rex Tillerson "a nominee for worst secretary of state ever" on Morning Joe on Tuesday, throwing in a comparison to Cambodian dictator Pol Pot for good measure, Mediaite reports.

"The State Department is also part of the machinery of government and that machinery has to run in order for normal things to happen like having relationships with foreign countries or having consular services for U.S. people, or doing all the things the State Department has to do, " Stephens told the Morning Joe hosts. "And Tillerson seems to be of a kind of Maoist school, in which it's — maybe it's Pol Pot."

"Wow," Scarborough jumped in. "If that is in fact the case, that is like one of the worst secretaries of state of all time."

"I don't mean killing fields," Stephens was quick to clarify. Catch up on what he did mean below. Jeva Lange