What the First Mars Colonists Should Expect From the Journey


If humanity ever gets serious about colonizing Mars, recruiting people to make the journey should be the least of our worries. When the Dutch nonprofit Mars One called for volunteers in 2013 to join its inaugural Mars mission, more than 200,000 people applied. And Mars One didn't dance around the nature of the trip: Aspiring astronauts knew they were signing up for a one-way ride.

But a willingness to die on the Red Planet is but one small prerequisite for getting there. Before leaving Earth, Mars-bound travelers must prepare for the physical challenges, like g-forces and microgravity. Passengers might also want to remove their gall bladder and appendix before the flight to avoid any rupturing due to pressure changes.

After the 150-day voyage through space, the real trial begins. Things we take for granted on Earth, like Wi-Fi, electricity, and access to the outdoors, will be hard to replicate on Mars. Beyond simply surviving, the first colonists will be tasked with making Mars habitable for future generations. Terraforming the planet to support life will be a centuries-long process.

To learn more about what it could take to travel to and survive on Mars, check out the below video from ASAP Science.

[h/t Nerdist]

Does Sound Travel Faster or Slower in Space?


Viktor T. Toth:

It is often said that sound doesn’t travel in space. And it is true … in empty space. Sound is pressure waves, that is, propagating changes in pressure. In the absence of pressure, there can be no pressure waves, so there is no sound.

But space is is not completely empty and not completely devoid of pressure. Hence, it carries sound. But not in a manner that would match our everyday experience.

For instance, if you were to put a speaker in interstellar space, its membrane may be moving back and forth, but it would be exceedingly rare for it to hit even a single atom or molecule. Hence, it would fail to transfer any noticeable sound energy to the thin interstellar medium. Even the somewhat denser interplanetary medium is too rarefied for sound to transfer efficiently from human scale objects; this is why astronauts cannot yell to each other during spacewalks. And just as it is impossible to transfer normal sound energy to this medium, it will also not transmit it efficiently, since its atoms and molecules are too far apart, and they just don’t bounce into each other that often. Any “normal” sound is attenuated to nothingness.

However, if you were to make your speaker a million times bigger, and let its membrane move a million times more slowly, it would be able to transfer sound energy more efficiently even to that thin medium. And that energy would propagate in the form of (tiny) changes in the (already very tiny) pressure of the interstellar medium, i.e., it would be sound.

So yes, sound can travel in the intergalactic, interstellar, interplanetary medium, and very, very low frequency sound (many octaves below anything you could possibly hear) plays an important role in the formation of structures (galaxies, solar systems). In fact, this is the mechanism through which a contracting cloud of gas can shed its excess kinetic energy and turn into something compact, such as a star.

How fast do such sounds travel, you ask? Why, there is no set speed. The general rule is that for a so-called perfect fluid (a medium that is characterized by its density and pressure, but has no viscosity or stresses) the square of the speed of sound is the ratio of the medium’s pressure to its energy density. The speed of sound, therefore, can be anything between 0 (for a pressureless medium, which does not carry sound) to the speed of light divided by the square root of three (for a very hot, so-called ultrarelativistic gas).

This post originally appeared on Quora. Click here to view.

The Orionid Meteor Shower Peaks This Weekend


October is always a great month for skywatching. If you missed the Draconids, the first meteor shower of the month, don't despair: the Orionids peak this weekend. If you've ever wanted to get into skywatching, this is your chance.

The Orionids is the second of two meteor showers caused by the debris field left by the comet Halley. (The other is the Eta Aquarids, which appear in May.) The showers are named for the constellation Orion, from which they seem to originate.

The shower is expected to peak overnight from Sunday, October 21, to Monday, October 22, when you can plan to see 15 to 20 super-fast meteors per hour. The best time for viewing is between 2 a.m. and 5 a.m., when Orion appears completely above the horizon. Make a late-night picnic of the occasion, because it takes about an hour for your eyes to adjust to the darkness. Bring a blanket and a bottle of wine, lay out and take in the open skies, and let nature do the rest.

There's a chance that the Moon might interfere with the meteors' visibility, according to Space.com. Leading up to its full state on October 24, the Moon will be in a waxing gibbous phase, becoming larger and brighter in the sky as the Orionids speed past Earth. Limiting light pollution where you can—such as by avoiding city lights—will help.

If clouds interfere with your Orionids experience, don't fret. There will be another meteor shower, the Leonids, in November, and the greatest of them all in December: the Geminids.

A version of this story appeared in 2017.