Tuesday, February 21, 2017

As hard as ... hydrogen?

At sufficiently high pressure, hydrogen liquefies starting at about 33 Kelvin.(*) That's cold. At about 14 Kelvin and yet more pressure, hydrogen will become a solid. And, it has been theorized since 1935, under enough pressure solid hydrogen can take metallic form.

(*) For mysterious reasons, absolute temperatures are shown in units of Kelvin, and not (as every other temperature scale would suggest) degrees Kelvin.

Not quite this easy
How much pressure? In round numbers, call it five million standard atmospheres. The amazing thing is, Harvard scientists reported last month that they had formed metallic hydrogen in the lab. "U.S. scientists create metallic hydrogen, a possible superconductor, ending quest." That's seriously cool. And high pressure.

Monday, February 13, 2017

This (maybe) is how the world ends ...

SF writers enjoy wreaking (fictitious!) mass destruction, and I'm no exception. In Dark Secret, for example, I pretty much sterilized the solar system with a gamma ray burst. (That's not a spoiler ... you find this out early in the novel. The story is all about what comes after the discovery of that imminent danger.)(*)

Amazon link
(*) I know what you're thinking: gamma rays travel at light speed -- because they are (high-frequency) light. If the arrival of gamma rays is the first you know about a GRB in the galactic neighborhood? Well, you're toast. That said, one of the mechanisms that can produce a GRB emits "I'm going to blow" indications before the actual blast (warnings which you won't detect without a gravitational-wave observatory, such as, but more sensitive than, LIGO).

How else, at a global or grander level, might things go Really Bad? I haven't done a death-by-asteroid novel (yet), but rocks from the sky are popular among my peers. (Though not so much with dinosaurs. Just sayin'.) A recent study suggests that asteroids may pose a bigger risk to us homo saps than formerly supposed. See "Fresh craters point to constant 'churning' of moon's surface." The takeaway: More than 200 new craters popped up on the moon over the past seven years – a third more than expected.

And the moon, after all, is quite nearby ...

Tuesday, February 7, 2017

The universe never ceases to amaze

A few wonders (some still at the speculation stage, admittedly) to ponder:

Light's not only pushy, it can be a drag. "Sun's own light may be slowing its surface spin."

A little light music ...

One of the key parameters in modern cosmological thinking is Hubble's Constant -- and we may not yet know its value. "HOLiCOW! Astronomers measuring the expansion of the universe confirm that we still don’t understand everything."

Pulsars are very power emitters of energy in radio frequencies. Pulsars pulse with metronomic regularity -- except, apparently, not all of them. "Astronomers discover two pulsars with an 'off' switch: Now you see them, now you don’t." (Shades of the "on-off star" in Vernor Vinge's excellent A Deepness in the Sky.)

Rock of ages ...

And again close to home, "The solar system’s weirdest asteroid has frozen water on its surface: 16 Psyche, a metallic relic of the early solar system, just got weirder." (Does 16 Psyche ring a bell? Well it might. Just last month NASA picked it as the target for a future asteroid mission: "NASA Selects Two Missions to Explore the Early Solar System.")
And perhaps that's enough weird for one post ...