Another stunning example of gravitational lensing in deep space revealed by #JWST.

And there is a single Milky Way star in this image.

Everything else is a galaxy. This view from @NASAWebb @ESA_Webb shows galaxy cluster PLCK G165.7+67.0 (also called G165), an enormous gravitational mass about 3.6 *billion* lightyears away that's so big it's bent the light of yet more distant objects behind it.

Friends, a few weeks ago I told you about something called Phantom—the Venus balloon mission concept I've been leading since January.

In July, we successfully flight-tested a subscale prototype of our balloon in the Nevada desert.

Now we've a video of those tests.

Take a look. This video documents just a tiny bit of the *enormous* amount of work folks have put into developing these balloons—much of that work predating my joining the mission concept team.

Importantly, these tests validate the technologies we hope to propose to NASA for eventual flight.

This. Is. Amazing.

NASA's #ParkerSolarProbe was able to image the surface of #Venus from space in a way we didn't think possible before!

Here, we can see the Aphrodite Terra highland *glowing* through the clouds (left), exactly where radar data tell us it should be (right)! Venus' thick cloud layer obscures the surface from space at visible wavelengths—but there are some "windows" at near-infrared wavelengths where cameras can see through to the surface.

PSP took these images at a wavelength not thought to be able to penetrate the clouds before.

A quick 🧵 about the *size* of the #HungaTonga eruption:

Volcanic eruptions are generally assigned a VEI—Volcanic Explosivity Index—value.

This scale is a general indicator of the explosive character of an eruptive event.

1/ This scale, described by Christopher Newhall and Stephen Self in a 1982 paper, is a general indicator of the explosive character of an eruptive event, and reflects the interplay of an eruption's magnitude, intensity, and energy release rate.

2/

I need you to know I'm being completely serious here.

We have no idea what's inside Uranus. We really don't have a clue what's inside this or there other "ice giant", Neptune.

It's possible that there's a rocky interior, perhaps at least as large as Earth. There might be a water–ammonia ocean above that rocky centre, topped with a thick atmosphere.

But we don't know.

The Solar System is *full* of incredible and fascinating worlds!

Mercury.
Venus.
Earth.
The Moon.
Jupiter.
Saturn.
Uranus and Neptune.
Ceres, Vesta, and the other main asteroid belt bodies.
The myriad other minor bodies scattered across the System.

Every one of them amazing! 🥰 People are pointing out that I forgot somewhere important!

Somewhere that fascinates everyone, that we need to explore more, that holds a special place in our heart.

I am so sorry, Pluto!

We have a new paper out in @PNASNews.

We found stuff that moved on #Venus.

Let's talk about it.

A 🧵 Most rocky worlds are what we call "one-plate planets": they have a single, continuous outer shell that we call the lithosphere.

Mercury (shown here), Mars, the Moon, Io... all one-plate planets.

(2/n)

Psst.

Interested in learning more about #Venus—and why @NASA's decision to go back there with the #VERITAS and #DAVINCI+ missions is such a big flippin' deal?

Read on.

(a 🧵 on comparative planetology) It all comes down to one simple question:

Why is Earth's sibling not its twin?

(Credit to @efrankplanetary for that line.)

Venus and Earth are the same(ish) size, age, and composition (in roughly the ~same proportions), orbiting the same star.

So, uh... what's going on?

Lawyer reassures judge that he is, in fact, not a cat.

https://twitter.com/MikaelThalen/status/1359209202292428800

The cat's panicked expression

Here's live coverage of the UAW @HopeMarsMission in English—the spacecraft is going to make its orbital insertion burn *in one minute*!! (1030 hrs Eastern)

#ArabsToMars

We should know whether the burn started successfully at around 1041 hrs Eastern

Normalise backing off from things when you realise you're overcommitted/out of spoons—a short, personal 🧵

Yesterday, I let the organisers of an upcoming conference know that I was withdrawing my abstract.

I really didn't want to do this.

(1/) But I realised that I had way too much on my plate to get my presentation done.

Bad planning? Maybe. But a bunch of new stuff arose between the abstract and now.

So after thinking long and hard about it, and prioritising what I absolutely *have* to do, I made the call.

(2/)

I don't know who needs to hear this, but planets are basically just big chemical processing engines (Could be that no one needs to hear this. That's OK.)

OK, buckle up, kiddos—here's a 🧵 on our new Geology paper about the enigmatic tesserae on #Venus, and what our new results mean for our understanding of the Hell Planet

Here we go!

https://twitter.com/ThePlanetaryGuy/status/1306630436836212741

First off: what *are* the tesserae (sing. "tessera")?

In short: dunno! Ha.

The longer answer is that they're very heavily tectonically deformed rocks, and where they're found they're the oldest things around: everything else is on top of them.

Here's what they look like:

Things have quietened enough that I'm going to share my thoughts about the detection of #phosphine on #Venus announced yesterday.

In short: this is a BIG fucking deal. And here's why:

(a 🧵) Phosphine (PH₃) is a fairly rare gas. It forms in giant planets, like #Jupiter, because of the extreme conditions inside them (and because of their hydrogen-rich atmospheres). Neither condition applies to Venus.

PH₃ is also produced by biological activity.

At 8:32 am Pacific time, May 18, 1980, it happened.

#MountStHelens exploded, producing the largest landslide ever recorded, sending a tower of rock and ash 19 km into the stratosphere, and killing 57.

I've added the Empire State Building to this image for scale.

A thread: A shallow earthquake caused the entire northern flank of the volcano to slide. The reduced pressure allowed a huge "cryptodome" of hot, pressurised magma inside the volcano to explode—creating a lateral blast that flattened trees for tens of kilometres.

Yesterday, @geo_spatialist posted this *gorgeous* rendering of a geological map of #Ireland from 1878.

Because I'm procrastinating, here's a short thread on the geology of some of the locales around Ireland, as shown by this map

(1/n) First up: the Wicklow Mountains (white box on map to the right).

These mountains are a) actually not really mountains at all (just big hills), and b) exposed granite intrusions that were pushed up when an ancient ocean called Iapetus closed up ~420 Myr ago (plus or minus)

(2/n)

As people are tucking into Easter eggs today, here's a list of some of the *absolute worst* substitutes for chocolate eggs that #geology can offer you. Consider yourself warned.

A THREAD

(1/n) Type: onion-skinned weathering of massive rocks (including sandstones and granites).

How: formed by weathering along spheroidal fracture planes within the rock mass

Why is bad: it's rock, so will break your teeth, and doesn't at all taste like chocolate

(2/n)

And the shortlist for #AmericasNextDiscoveryMission has been announced!

@NASA has picked four missions for detailed, 9-month studies under the Discovery-class cost cap; one or two mission finalists will be actually selected for flight around the end of the year.

Read on!

(1/n) The first is DAVINCI+ (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging Plus), which is a mission to take detailed chemical measurements as it plunges through the Venus atmosphere!

(2/n)

Day 3 of the #VeneraD workshop!

And we're pivoting away from landing sites now and turning to cloud habitability - with the first talk given by Michael Way, about possible conditions on early #Venus! The next talk is from Shawn Domagal-Goldman, who's describing (remotely, from the US!) how #Venus offers us a useful natural laboratory to understand planetary habitability in general

#VeneraD