Philip Plait's Blog, page 22

Fly me to the Moon… and then a near-Earth asteroid

Well this is interesting: NASA is launching a spacecraft to explore asteroids on Artemis I, the first test flight in their push to return to the Moon.

The spacecraft is called Near-Earth Asteroid, or NEA Scout, and get this: It’s using a solar sail as propulsion, the first interplanetary mission to do so!

OK, first: Artemis I is a full-up test flight of the Space Launch System (or SLS) and Orion capsule. It will be uncrewed, and will send Orion into orbit around the Moon for a week or so befor...

Seeing stars born at the dawn of the Universe

Astronomers have found six galaxies that look to be at the thin hairy edge of the observable Universe, so far away that we see them not long after their very first stars were born — the cosmic dawn.

Incredibly, just seeing stars in them at all means we can learn about what they were like even earlier in their history, perhaps around 100 million years after the birth of the Universe itself!

There are two key physical properties of the Universe needed to make an observation like this. One is tha...

A newly discovered and huge structure in the Milky Way was hidden right in front of us

We think of the Milky Way galaxy as having well-defined spiral arms swooping around it, starting near the galactic center and smoothly stretching to the outer reaches.

However, a team of astronomers has found a big surprise: By examining stars in a nearby spiral arm they’ve discovered a new structure that sticks out from it like an unruly cowlick, and amazingly one that contains some of the most celebrated and best-studied nebulae in the galaxy. It was hidden in plain sight all along, like find...

Narrowing down the source of the dinosaur-killer asteroid

Where did the dinosaur-killer asteroid come from?

This is a question of great scientific and titillating public interest. We know that 66 million years ago an asteroid 10 kilometers in size slammed into the Earth just off the coast of what is now the Yucatan Peninsula in the Gulf of Mexico, carving out the 180-kilometer-wide Chicxulub crater and setting off a complicated chain of events that killed off something like 75% of all species on the planet including all the non-avian dinosaurs, so yea...

Saturn's core is big and fuzzy — and its gravity is written in the rings

Saturn's rings are the most magnificent and exquisitely shaped structures in the solar system. And, it turns out, they make an excellent gravitational seismograph to determine what's going on inside the planet itself.

Although not connected physically, the planet and rings are connected gravitationally.

New work analyzing images of Saturn's rings show that waves in the rings are created by changing gravity from Saturn's core as it sloshes around inside the planet like a bag of jelly, and which...

Orange you glad I have another optical illusion to confuse your brain?

So who would you trust more: me, your cosmic host on this journey through the Universe; or your brain, which is a squishy lump of meat trapped forever inside a skull into which it barely fits?

Surprise! It's me.

I can prove this. For example, remember the Internet furor a few years back over a dress that some people swore was white and gold, and others furiously defended it as being black and blue?

This was a fantastic example of how messed up our brains are about color (and how tenaciously w...

We're probably safe from an impact by the asteroid Bennu for another 300 years

Well, some much-needed good news: A new paper has just been published showing that we're pretty safe from an impact by the near-Earth asteroid Bennu until at least the year 2300.

Cool.

Mind you, there's a slight chance of an impact on September 24, 2182, but a) it's only about 0.04%, and 2) that's a long time from now.

Bennu is a half-kilometer wide asteroid on an orbit that takes it from about 130 to 200 million kilometers from the Sun, one which also crosses very close to the orbit of our o...

Good news: Immensely powerful red dwarf superflares may not sterilize their planets

Any aliens living on a planet huddling close to a red dwarf star can breathe a sigh of relief (assuming they breathe, and can sigh, and feel relief): It’s possible extremely powerful explosive stellar flares don’t sterilize the planets as previously thought.

Maybe.

Red dwarf stars are much smaller, cooler, and dimmer than the Sun. Also unlike the Sun red dwarfs are fully convective, meaning hot plasma rises from their core all the way to their surface (in the Sun the convective region is much ...

The Perseids peak this week! Here's how to watch one of the best meteor showers of 2021

The sky is falling! Or it will on the evening of August 12/13, when the Perseid meteor shower reaches its peak. This is a reliable shower, with around 60–100 meteors per hour (or about one per minute), though sometimes more are seen.

Even better: The Moon is a thin crescent and sets a couple of hours after the Sun, so it won't out any meteors with its light.

What follows below is a detailed checklist of what you need to watch the shower (modified from articles from years past), but for the cr...

Confirmed! A tiny nearby exoplanet with only 40% of Earth's mass

A planetary system just 35 light years from Earth hosts four and possibly five planets. This includes one (if it exists) that's squarely in its star's habitable zone, and another that's the lightest-weight planet ever found using the radial velocity method: It has only 40% of Earth's mass. That's pretty cool.

The host star is a red dwarf called L98-59, which is substantially smaller, cooler, and dimmer than the Sun, shining only 1% as bright as our own star. Three planets were already known to ...