The future of NASA's aging Voyager spacecraft, which over the last 45 years have collected data no human-made probes have ever gathered, is starting to come into sharper focus.
Why it matters: Voyager 1 and Voyager 2 are the only functional human-made spacecraft currently in interstellar space.
In the midst of an unprecedented heat wave, the U.K. on Tuesday broke its national record for the highest temperature ever registered, with a provisional reading of 104.36°F (40.2°C) at London's Heathrow Airport, according to the country's weather service.
Why it matters: This is the first time the U.K. has breached this temperature that is more common in tropical and desert climates, and studies point to climate change as a key factor behind the scorchingly hot temperatures.
While the heat in Europe is garnering the most headlines, a potent heat wave is hitting the U.S. as well. The heat stretches from the Canadian border to the U.S. border with Mexico, with 100 million under heat warnings and advisories.
Driving the news: Heat warnings on Tuesday cover the entire state of Oklahoma and the vast majority of Texas, where the electrical grid will once again be tested.
Why it matters: The fact that we've arrived at this point — with deadly extreme heat virtually shutting down major industrialized nations, but without changing course to curb greenhouse gas emissions — is depressing and baffling to the scientists who have been warning about this moment for years.
The U.K. has likely endured its "warmest night," and its hottest day ever is forecast to follow on Tuesday as Europe's historic heat wave spreads north.
What's happening: Temperatures were above 25°C (77°F) in some parts of the U.K. overnight, per provisional Met Office data, as its first-ever Red warning for heat covers much of England. Temperatures could exceed 40°C (104°F) for the first time Tuesday. Southern Germany and eastern France were forecast to see similar temperatures.
Some 40 million Americans are under heat alerts due to "dangerous and intense," potentially record-breaking heat across the Plains and Mississippi Valley that's expected to expand into the Southeast this week.
The big picture: The National Weather Service issued a red flag warning for Texas, and there are heightened fire dangers in several states. Firefighters are already battling 89 large fires across 12 states. An excessive heat warning was in effect for all of Oklahoma for Tuesday, with highs of 110-112°F expected — 16°F above the state's average.
An unprecedented heat wave is underway in France and the U.K. that is likely to topple all-time national high temperature records and potentially kill several thousand people. The scorching heat is moving north into a more vulnerable region after tormenting Spain and Portugal.
The manager of most of the United Kingdom's railway network warned passengers to not travel over Monday and Tuesday unless "absolutely necessary" because of a potentially record-breaking heat wave underway in France and the U.K.
Why it matters: Heat waves can have a brutal effect on infrastructure — like railways and tarmacs — not designed to withstand abnormally high temperatures, which can disrupt transportation for thousands of people when they should not be outside for a prolonged period of time.
U.K. Prime Minister Boris Johnson, who recently resigned from his post but is staying on until a replacement is chosen, has faced backlash for missing multiple emergency Cabinet meetings to discuss the country's dangerous heat wave.
Why it matters: The unprecedented heat wave is likely to set a new all-time national high temperature record, with the U.K. Met Office forecasting the country's first-ever occurrence of a temperature of 104°F (40°C) during the event, Axios' Andrew Freedman writes.
