Why it matters: Commentators often refer to the middle of the U.S. as a single entity, like "middle America" or, more pejoratively, "flyover country." This makes the economic vitality of the northern plains all the more striking.

• As is clear in the chart above, most working-age adults in the region have jobs. And people born into low-income households are moving into the middle class with greater ease than other Americans.
• The top six metro areas in terms of upward mobility — defined as the average income of people with the poorest parents — are all in the northern plains.

The region's' prosperity has been driven in part by a massive expansion of shale oil and gas production in the Bakken region of North Dakota and elsewhere in the region.

• "Energy creates cyclical but significant job creation, small firm growth, and consumer activity," Mark Muro, who co-authored the report, tells Axios.

The boom has driven North Dakota to the top of the economic indicators:

• Its wage growth has been 2.3% a year, compared with 0.8% for the rest of the country.
• 80.9% of the state's working-age population was working, second only to Minnesota, at 81.1% — again leading the country.
• In hard economics, GDP per capita in North Dakota rose at 3% a year, the fastest in the country; productivity grew at a sizzling at 2.4% annual growth, while it was flat for the rest of the nation.
• North Dakota also had the 10th-lowest poverty rate in the country, at 10.5%; Minnesota was the fourth-lowest at 9.9%.

But, but but ... The boom has brought growing crime, especially against women, and environmental destruction.

• "This economic prosperity has come with devastating social by-products," says Richard Edwards, director of the Center for Great Plains Studies at the University of Nebraska. “We are paying a high, high price for such ‘prosperity.’”

Other factors, in addition to the fracking boom, have buttressed the region's economy.

• In rural areas, depopulation has resulted in better wages for those left behind. "Demand for an increasingly limited number of individuals is resulting in an increase in income" and better job prospects, Joe Brusuelas, chief economist of RSM US, tells Axios.
• And in cities such as Omaha, Lincoln, Sioux Falls, and the Twin Cities, industries are thriving along with the rest of the country. Employers can easily find workers among migrants from the surrounding countryside, said Edwards, the University of North Dakota professor.

Go deeper:

• Two Americas: The geographical wage gap has stopped closing
• Why rural counties are dying in America

The big picture: The first discovery of a planet orbiting a star other than the sun was only thirty years ago.

• In 1988, scientists announced the discovery of a planet orbiting a pulsar nearly 5,000 light years away.
• Over the last three decades, the pace of discovery has only quickened: More than half of confirmed exoplanet discoveries have been announced in the last four years.

Most of the recent discoveries were detected by the Kepler space telescope, the first space-based telescope designed specifically to find earth-size planets orbiting other stars. "Kepler was a complete game changer," MIT astronomer Sara Seager told Axios.

• That's why Seager is enthusiastic about analyzing the findings from Kepler's successor, the Transiting Exoplanet Survey Satellite (TESS), which was launched in April.
• TESS searches for Earth-like planets in an area of the sky closer to Earth than where Kepler looked, making it easier for astronomers to later confirm the planets' existence by calculating their mass.

Since TESS began making observations in July, it has already made two confirmed exoplanet discoveries. Scientists expect it to make thousands more as it sends its findings back to Earth. "Every month we get a deluge of data," Seager said.

What's next: Neither TESS, nor Kepler, nor any of the massive land-based telescopes searching the galaxy for planets, are able to capture actual images of exoplanets.

• Instead, they detect their presence by measuring changes in their stars' light over time.

The bottom line: The technology for capturing even pixel-sized images of exoplanets — which would help scientists better assess whether their atmospheres are suitable for life — is still many years away.

By the numbers: 1,706 Democratic congressional candidates have spent or raised money during the current cycle. That breaks the previous record set in 2010, when 1,688 Republican congressional candidates registered with the FEC.

• But the enthusiasm gap between parties was far larger in 2010. During that cycle, only 1,136 Democratic candidates ran for Congress, compared to 1,550 GOP candidates this time around.

The bottom line: The number of candidates in itself doesn't guarantee election victories. But it's one more sign of how motivated Democrats are this year, and that could lead to victories if it translates into high Democratic voter turnout.