Oceans covered much of Mars in the ancient past, and seasonal dark streaks observed on the Red Planet's surface today may be caused by salty flowing water.įurther, NASA's Curiosity rover has found carbon-containing organic molecules and "fixed" nitrogen, basic ingredients necessary for Earth-like life, on the Martian surface.įarther afield, observations by NASA's Kepler space telescope suggest that nearly every star in the sky hosts planets - and many of these worlds may be habitable. The key is to build a body of evidence that cannot be explained away by anything other than biology, says Vago.For example, oceans of liquid water slosh beneath the icy shells of the Jupiter moons Europa and Ganymede, as well as that of the Saturn satellite Enceladus. If we happen upon past life relics, we need to be able to tick a good number of independent biosignatures and to do it repeatedly with various samples, says Vago. Depending on how they were entombed, they may be preserved, he says. The microbes would have died long ago the cell membranes would have ruptured and their chemical guts spread into the geological record, says Vago. When organisms are metabolically active, they can repair any radiation induced damage so we would have access to a high concentration of biomolecules, he says. Present life would give itself away via the sheer quantity and good state of preservation of the biomolecules, says Vago. ![]() When it comes semantics at a hypothetical post-detection press conference, he says that rather than ‘this was/is life,’ official statements are more likely to read: ‘Currently, the only explanation for our results is life we could not think of any other way to produce our findings.’ Will MOMA be able to differentiate between past and present life? We need both sides for a consistent interpretation, he says. The optimists will declare to have seen evidence for life while the pessimists will carefully search for non-biological explanations, says Goesmann. While the identification of molecules will most likely contain little ambiguity, the significance for “life detection” is tricky, he says. What is MOMA’s biggest scientific challenge?Ĭonverting results into significance, Fred Goesmann, MOMA’s Principal Investigator, and a planetary scientist at Germany’s Max Planck Institute in Gottingen, told me via email. The probability that we may find something that is suggestive of life is something like 50%, he says. The probability that we will find organic molecules, I think is like 100%, says Vago. This will enable the team to avoid sample contamination by perchlorates, colorless and odorless salts, that can be an unwanted byproduct of the kind of heat needed to conduct such sample analysis. Instead of thermal heat, MOMA will use a laser to separate the largest organic compounds from the minerals to which they were originally bound. Then these gas phase chemical samples will undergo onboard analysis to determine if they look promising for biology in both their makeup and their distribution. To do so, MOMA will either use heat or ultraviolet laser pulses to convert chemical species in the samples into a gas phase. ![]() Mass spectrometers measure the chemical makeup and mass of given substances in gaseous states. MOMA must first vaporize the compounds it collects so they can be detected by the instrument’s mass spectrometer. Dig a foot and a half below the surface and the temperature is minus 60 degrees Fahrenheit it's a wonderful freezer, he says. Once Mars lost its surface water, it turned very cold, says Vago. The ensuing cold temperatures beneath the surface would also have aided in their preservation. ![]() Once Mars lost its water and dried out, these microbial colonies would have turned into microfossils preserved by this sedimentary ash. Because Mars is thought to have been very volcanically active at the time, ash from its volcanoes would have fallen on its ocean’s surface. Some four billion years ago, it’s likely there were microbial colonies living in some sort of hydrothermal system beneath the surface of Oxia Planum.
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Other programs CalifeĬalife lets you run commands as another user by typing your own password, if authorized. Notably, systemd-based systems will prompt you for the root password when you boot this way. On many systems booting into single user mode will give the user access to a root shell without prompting for a password. You can also get to single user mode by using the telinit command: telinit 1 however, this command requires you to already have gotten root privileges via some other method in order to run. Typically, this is the smallest number of services required to have a usable system. Rather, the system will only start the services defined for run-level 1. Note that booting into single-user mode is not the same as booting the system normally and logging in as root. You can boot into single user mode by passing single or emergency on the kernel command line. This is intended primarily for emergency maintenance situations where booting into a multi-user run-level is not possible. Single user mode, or run-level 1, also gives you root privileges. Logging in directly as root is mainly useful in emergency situations, such as disk failures or when you've locked yourself out of your account. Be very careful, and avoid running complex applications as root as they might do something you didn't intend. If there is a root password set and you are in possession of it, you can simply type root at the login prompt and enter the root password. (The point is to limit the damage if the root password is accidentally leaked to someone.) Logging in as root On some systems, you need to be in group number 0 (called wheel) to use su. ![]() To run multiple commands as root, it is more convenient to start an interactive shell. Note that you need quotes so that the command is not parsed by your shell, but passed intact to the root shell that su runs. The command to run must be passed using the -c option. ![]() When run with no user specified, su will default to the root account. It lets you run a command as another user, provided you know that user's password. The su command exists on most unix-like systems. Read the sudoers man page for more information use sudo visudo to edit the sudoers file. Sudo is very configurable for example it can be configured to let a certain user only execute certain commands as root. The difference is that -i re initializes the environment to sane defaults, whereas -s uses your configuration files for better or for worse.įor more information, see the sudo website, or type man sudo on your system. Sometimes, it is more convenient to run an interactive shell as root. If you need to run several commands as root, prefix each of them with sudo. a typo.) It is often configured to not ask again for a few minutes so you can run several sudo commands in succession. (The purpose is to limit the damage if you leave your keyboard unattended and unlocked, and also to ensure that you really wish to run that command and it wasn't e.g. Sudo requires that you type your own password. If you don't know a separate root password, use this method. This is the preferred method on most systems, including Ubuntu, Linux Mint, (arguably) Debian, and others. Running a shell command as root sudo (preferred when not running a graphical display)
![]() “EVs are fast,” Ahire says, “and the eCrate performance is equal to or better than an internal combustion engine.” While so much industry talk these days is focused on electrification, Ahire makes clear that Chevrolet Performance respects both technologies. We decided there’s absolutely no need for a fake engine sound.” Lingenfelter says the original plan was to install an emulator that would re-create the roar of a V8 engine that enthusiasts love: “But when we finished the car and heard the electric sound, it’s kind of a jet engine sound, not loud, but it has a power to it - we loved it. A traditional install where they couldn’t see anything would not have been as accepted.” “The El Camino brings the electric side of it to a much more visual level. “If they can see it, they can evaluate it and ask questions,” Lingenfelter says. Lingenfelter instead mounted all the electronics and wires and components right under the hood to look like a regular engine. In place of the engine, most EVs offer a place for more stuff. ![]() Or at least nothing like what you find in a vehicle powered by internal combustion. Pop the hood on most production EVs, and what you typically see is nothing. The Lingenfelter team was purposeful from the start. “It’s a cool car and enthusiasts love it.” That’s one reason they chose the El Camino as the canary to send into the electrified coal mine. “We wanted this car to build a bridge for traditional car folks, to help them get past the mental barriers around electrification,” company owner and CEO Ken Lingenfelter says. |
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