Tag: astronomy

Venus

This video makes it look like Venus is much closer to the sun than it actually is (100M km) but still, well done.

2014-07-02: Colonizing Venus

If the thought of Thanksgiving Dinner on Venus gives you the heebie jeebies, you don’t even need to think about plunging into the roiling atmosphere with nothing but a cheap plastic heat shield and a thin balloon to save you from the crematorium that yawns down below. Dangle the bird into the depths of the Stygian hell, feast as someone who walks between worlds and lives on an airship that rides the hell born winds 48km above a surface so hot it glows visibly red.

2014-07-03: Venus is a good fraction of solid surface in the solar system.

2020-09-18: Phosphine on Venus

observations indicate a level of phosphine at 20 parts per billion. That may sound low, but it turns out that from what we currently know, on Venus it’s hard to make anywhere near that much. The phosphine was seen at altitudes of at least 50 km. The environment there is pretty hostile to phosphine, which would decompose fairly rapidly. They estimate that that it should all be gone in less than 1 ka at that level, and probably much faster. So something must be actively making it to keep the levels up. But what?

2021-01-14: Jupiter killed Venus?

we present the results of a study that explores the effect of Jupiter’s location on the orbital parameters of Venus and subsequent potential water-loss scenarios. We argue that these eccentricity variations for the young Venus may have accelerated the atmospheric evolution of Venus toward the inevitable collapse of the atmosphere into a runaway greenhouse state. The presence of giant planets in exoplanetary systems may likewise increase the expected rate of Venus analogs in those systems.

DNA precursors in space

Consider this: we have the capability to detect the presence of very specific molecules from 25k light years away. This is just mind-boggling.

Researchers have discovered prebiotic (pre-life) molecules in interstellar space that may have formed on dusty ice grains floating between the stars. The molecules were detected near the center of our Milky Way Galaxy — specifically, the star-forming region Sagittarius(Sgr) B2(N), which is the richest interstellar chemical environment currently known. 1 of the newly-discovered molecules, called E-cyanomethanimine (E-HNCHCN) is one step in the process that chemists believe produces adenine, 1 of the 4 nucleobases of DNA. The other molecule, called ethanamine, is thought to play a role in forming alanine, 1 of the 20 amino acids in the genetic code.

2014-10-03: Isopropyl cyanide, needed for life

Astronomers have detected radio waves within a giant gas cloud in interstellar space corresponding to an unusual carbon-based molecule called isopropyl cyanide, needed for life. Organic molecules usually found in these star-forming regions consist of a single “backbone” of carbon atoms arranged in a straight chain. But the carbon structure of isopropyl cyanide branches off, making this the first interstellar detection of such a molecule


2014-12-02: DNA itself can also survive in space. This makes Panspermia (and contamination of the seas of europa by humanity’s probes) more likely.

Surviving space flight, 1000°C temperatures, re-entry into Earth’s atmosphere, and landing, 35% of the DNA retained its full biological function

2022-03-13: Peptides can form on cosmic dust

Without any of the enzymes that biochemistry provides, the production of peptides is an inefficient 2-step process that involves first making amino acids and then removing water as the amino acids link up into chains in a process called polymerization. Both steps have a high energy barrier, so they occur only if large amounts of energy are available to help kick-start the reaction.

Because of these requirements, most theories about the origin of proteins have either centered on scenarios in extreme environments, such as near hydrothermal vents on the ocean floor, or assumed the presence of molecules like RNA with catalytic properties that could lower the energy barrier enough to push the reactions forward. And even under those circumstances, “special conditions” would be needed to concentrate the amino acids enough for polymerization. Though there have been many proposals, it isn’t clear how and where those conditions could have arisen on the primordial Earth.

But now a group of astrobiologists showed that peptides, the molecular subunits of proteins, can spontaneously form on the solid, frozen particles of cosmic dust drifting through the universe. Those peptides could in theory have traveled inside comets and meteorites to the young Earth — and to other worlds — to become some of the starting materials for life.

Proxima Centauri

The new planet we’ve found there is so very near our own that its night sky shares most of Earth’s constellations. From the planet’s broiling surface, one could see familiar sights such as the Big Dipper and Orion the Hunter, looking just as they do to our eyes here.

2012-10-19: Saturn as viewed from the moon vs Proxima Centauri viewed from Saturn

2020-04-25:

The proposal assumes a peak spacecraft velocity of 10% of the speed of light. Once launched out of Earth’s gravitational well, the remaining spacecraft is composed of 2 stages. The first stage accelerates the spacecraft to 0.1c, detaches from the second stage, and performs a smaller perpendicular burn to deflect its trajectory toward the Proxima Centauri AB binary system for a flyby of that solar system. The second stage decelerates a scientific payload and provides power and support during a decades-long period of exploration.

2022-03-15:

Why is it so difficult to detect planets around Alpha Centauri? Proxima Centauri is one thing; we’ve found interesting worlds there, though this small, dim star has been a tough target, examined through decades of steadily improving equipment. But Centauri A and B, the G-class and K-class central binary here, have proven impenetrable. Given that we’ve found over 4500 planets around other stars, why the problem here?

Proximity turns out to be a challenge in itself. Centauri A and B are in an orbit around a common barycenter, angled such that the light from one will contaminate the search around the other. It’s a 79-year orbit, with the distance between A and B varying from 35.6 AU to 11.2. You can think of them as, at their furthest, separated by the Sun’s distance from Pluto (roughly), and at their closest, by about the distance to Saturn.

The good news is that we have a window from 2022 to 2035 in which, even as our observing tools continue to improve, the parameters of that orbit as seen from Earth will separate Centauri A and B enough to allow astronomers to overcome light contamination. I think we can be quite optimistic about what we’ll find within the decade, assuming there are indeed planets here. I suspect we will find planets around each, but whether we find something in the habitable zone is anyone’s guess.

Exomoons

the first science project i helped fund made its first discovery. so exciting!

As part of the Hunt for the Exomoons with Kepler (HEK) project, the team analyzed recently released Kepler data and identified systems with transiting planets that show transit variations indicative of hidden companions, such as unseen moons or planets. The team identified the Sun-like star known as KOI-872 (KOI stands for Kepler Objects of Interest) as exceptional in that it shows transits with remarkable time variations over 2 hours.