【推荐1】What really happens during death? This question has greatly interested humankind for centuries.

Now, for the first time, scientists have recorded a dying brain, and they have made a shocking discovery: our life may truly flash before our eyes when we die.

A new study saw scientists from across the globe delve into the final moments of an 87-year-old man’s life. As published in the Frontiers in Aging Neuroscience journal, the patient died of a heart attack, and his doctors at Vancouver General Hospital in British Columbia recorded his brain in the process.

Researchers specifically studied the 30-second intervals before and after the patient’s heart stopped. What they discovered was that his life might have literally flashed before his eyes, as his brain produced neural oscillations (神经振荡). Commonly known as brain waves, neural oscillations essentially define the electrical activity of our brains. The oscillations occur at different frequencies and have generally been categorized into different states of consciousness.

In this case, the patient’s heart attack showed sudden changes in the patient’s alpha and gamma waves. This interaction has long been known to correlate with memory recall, dreaming, meditation, the processing of information, and conscious perception — in other words, flashbacks.

It’s important to note that this study is the first of its kind, as the live brain activity of a dying human being has never been measured like this before. On the other hand, these oscillations have been previously monitored in rats, which suggests the brain might launch the same biological response to death in multiple species. The study does provide certain considerations, however, such as the patient’s brain being damaged by bleeding and swelling while this activity was recorded.

Ultimately, the findings have forced us to redefine when life truly begins and ends — and not to grieve too deeply, though. Something we may learn from this research is: although our loved ones have their eyes closed and are ready to leave us to rest, their brains may be replaying some of the nicest moments they experienced in their lives.

【推荐3】Many are familiar with the potentially deadly danger caused by lightning, which is blamed for an average of 43 deaths in the United States each year, based on data from 1989 to 2018. However, the researchers recently uncovered a surprising and beneficial impact of lighting.

Published at the end of April in Science, the new study found that lightning may play a bigger role in global climate change than what was previously known by the   scientific community, “Lightning increases the atmosphere's ability to clean itself,” the researchers wrote in the study.

The study, which included efforts from nine atmospheric experts across a dozen universities and meteorological agencies, was based on an airborne research flight conducted by a NASADC-8 storm-chasing plane in 2012. The plane used to examine the top part of the top part of thunderstorm clouds, which are known as anvils (砧状云).

According to Dr.William Brune, a professor of meteorology and atmospheric sciences at Pennsylvania State University and co-author of the study, researchers initially thought there was a problem with the equipment on the plane, which was being used to measure the hydroxyl radicals（羟基自由基）in the atmosphere. But soon they realized the sharp increase they observed came along with lightning flashes.

Hydroxyl radicals, described as a “chemical cleaner” by Science Direct, are important chemical compounds (化合物) found in the atmosphere due to the reactive nature with other organic molecules (有机分子).

Researchers previously understood that lightning could help to clean the atmosphere, but there was no evidence that it could produce compounds like these radicals. As a result, the study estimates that somewhere between 2% and 16% of the cleaning that happens naturally in the Earth's atmosphere, is done by lightning.

Why is this significant? The existence of the hydroxyl radicals helps to reduce chemicals like carbon dioxide and methane in the atmosphere. These chemicals, known for greenhouse gases, have been proven to contribute to rising temperatures associated with climate change.