Tag Archives: Astrophysics

A Star Orbiting in the Extreme Gravity of a Black Hole Validates General Relativity

At the center of the Milky Way galaxy, nearly 26,000 light-years away, a cluster of stars circles close to the supermassive black hole known as Sagittarius A*. As these few dozen stars, called S-stars, approach the black hole—which is about four million times more massive than the sun—its immense gravitational force whips them around faster than 16 million miles per hour. In fact, the gravitational pull of Sagittarius A* is so intense that it warps the light from these stars when they stray too close, stretching the wavelengths toward the red part of the electromagnetic spectrum. Continue reading A Star Orbiting in the Extreme Gravity of a Black Hole Validates General Relativity

Four Types of Stars That Will Not Exist for Billions or Even Trillions of Years

The early universe was filled with strange and mysterious objects. Shortly after the Big Bang, large clouds of material may have formed black holes directly, without first coalescing into stars as we see today. Pseudo-galaxies lit up a sea of neutral hydrogen to make the universe transparent, releasing photons where before there was nothing but darkness. And short-lived stars made of nothing but hydrogen and helium may have flashed in and out of existence like sparks in the night. Continue reading Four Types of Stars That Will Not Exist for Billions or Even Trillions of Years

Gaze in Awe at Hubble’s Most Detailed View of the Triangulum Galaxy

Usually when astronomers talk about our neighboring galaxy, they’re talking about Andromeda, which is a cozy 2.5 million light-years away. But just a little farther—okay, 500,000 light-years farther—is another spiral galaxy, the third largest in our local group. Hubble has just released its most detailed view yet of that galaxy, which is known as Triangulum (can you see why?). Continue reading Gaze in Awe at Hubble’s Most Detailed View of the Triangulum Galaxy

Discovery of ‘Goblin’ Solar System Object Bolsters the Case for Planet Nine

Astronomers have discovered an object, dubbed “the Goblin,” in the outer reaches of the Solar System. The dwarf planet never gets any closer to the Sun than 6 billion miles, but experts say its orbital configuration points to the existence of a much larger, more distant planet —the elusive Planet Nine. Continue reading Discovery of ‘Goblin’ Solar System Object Bolsters the Case for Planet Nine

Explorers Will Face Dangerous Amounts of Radiation On Their Trip to Mars

Traveling to Mars is the next great step in humanity’s space journey. In Hollywood, the recent movie The Martian and television series The First present reaching the Red Planet as more of a near-term logistics challenge rather than a pie-in-the-sky space dream. NASA is currently orienting itself toward a “Moon to Mars” Mission, but the technical hurdles facing a Mars mission are still massive. One of the most difficult challenges is dealing with the dose of radiation any interplanetary astronauts would face. Meghan Bartels at Space.com reports that new data from the European Space Agency (ESA) has refined our model for radiation during the journey to and from Mars, and it doesn’t look good. Continue reading Explorers Will Face Dangerous Amounts of Radiation On Their Trip to Mars