Instruct: Given a question, retrieve relevant documents that answer the question.
Query: Are there rivers of liquid hydrogen outside of our solar system?
The Gliese 581 planetary system contains multiple planets that may be candidates for surface water, including Gliese 581c,[60] Gliese 581d, might be warm enough for oceans if a greenhouse effect was operating,[61] and Gliese 581e.[62]
The Taleghan solar hydrogen energy system is a stand-alone photovoltaic–hydrogen demonstration project in Taleghan, Qazvin Province, Iran. It is developed by the Renewable Energy Organization of Iran (SUNA).
As of December 2015, the confirmed liquid water in the Solar System outside Earth is 25-50 times the volume of Earth's water (1.3 billion cubic kilometers).[5]
A concept to provide low Earth orbit (LEO) propellant depots that could be used as way-stations for other spacecraft to stop and refuel on the way to beyond-LEO missions has proposed that waste gaseous hydrogen—an inevitable byproduct of long-term liquid hydrogen storage in the radiative heat environment of space—would be usable as a monopropellant in a solar-thermal propulsion system. The waste hydrogen would be productively utilized for both orbital stationkeeping and attitude control, as well as providing limited propellant and thrust to use for orbital maneuvers to better rendezvous with other spacecraft that would be inbound to receive fuel from the depot.
The four outer planets of the Solar System are gas giants. They share some atmospheric commonalities. All have atmospheres that are mostly hydrogen and helium and that blend into the liquid interior at pressures greater than the critical pressure, so that there is no clear boundary between atmosphere and body.
The objects of the inner Solar System are composed mostly of rock,[33] the collective name for compounds with high melting points, such as silicates, iron or nickel, that remained solid under almost all conditions in the protoplanetary nebula.[34] Jupiter and Saturn are composed mainly of gases, the astronomical term for materials with extremely low melting points and high vapour pressure, such as hydrogen, helium, and neon, which were always in the gaseous phase in the nebula.[34] Ices, like water, methane, ammonia, hydrogen sulfide, and carbon dioxide,[33] have melting points up to a few hundred kelvins.[34] They can be found as ices, liquids, or gases in various places in the Solar System, whereas in the nebula they were either in the solid or gaseous phase.[34] Icy substances comprise the majority of the satellites of the giant planets, as well as most of Uranus and Neptune (the so-called "ice giants") and the numerous small objects that lie beyond Neptune's orbit.[33][35] Together, gases and ices are referred to as volatiles.[36]
The demonstration project of the Taleghan solar hydrogen energy system was developed in 1996–2005. It is located at the altitude above sea level. The system consists of a 10 kW photovoltaic array, 3.5 kW electrolysis system with a hydrogen-production capacity of , a 0.4 kW proton exchange membrane fuel cell, 60 batteries and a hydrogen storage tank. The initial cost of the system was US$193,563.
Hydrogen sulfide has often been detected in the interstellar medium. It also occurs in the clouds of planets in our solar system.
Titan, the largest moon of Saturn, is the only known moon in the Solar System with a significant atmosphere. Data from the "Cassini–Huygens" mission refuted the hypothesis of a global hydrocarbon ocean, but later demonstrated the existence of liquid hydrocarbon lakes in the polar regions—the first stable bodies of surface liquid discovered outside Earth. Analysis of data from the mission has uncovered aspects of atmospheric chemistry near the surface that are consistent with—but do not prove—the hypothesis that organisms there if present, could be consuming hydrogen, acetylene and ethane, and producing methane.
A concept to provide low Earth orbit (LEO) propellant depots that could be used as way-stations for other spacecraft to stop and refuel on the way to beyond-LEO missions has proposed that waste gaseous hydrogen—an inevitable byproduct of long-term liquid hydrogen storage in the radiative heat environment of space—would be usable as a monopropellant in a solar-thermal propulsion system. The waste hydrogen would be productively utilized for both orbital stationkeeping and attitude control, as well as providing limited propellant and thrust to use for orbital maneuvers to better rendezvous with other spacecraft that would be inbound to receive fuel from the depot.
Astrooceanography is the study of oceans outside planet Earth. Unlike other planetary sciences like astrobiology, astrochemistry and planetary geology, it only began after the discovery of underground oceans in Saturn's Titan and Jupiter's Ganymede. This field remains speculative until further missions reach the oceans beneath the rock or ice layer of the moons. There are many theories related to celestial bodies in the Solar System, from oceans made of diamond in Neptune to a gigantic ocean of liquid hydrogen that may exist underneath Jupiter's surface.
Slush hydrogen is a combination of liquid hydrogen and solid hydrogen at the triple point with a lower temperature and a higher density than liquid hydrogen. It is formed by bringing liquid hydrogen down to nearly the melting point (14.01 K or −259.14 °C) that increases density by 16–20% as compared to liquid hydrogen. It is proposed as a rocket fuel in place of liquid hydrogen in order to improve tankage and thus reduce the dry weight of the vehicle.
After the Mariner missions proved there was no life on Mars, she never returned to her solar system. When she started to write planetary romance again in the 70s, she invented a new solar system outside our own.
Gas giants consist mostly of hydrogen and helium. The Solar System's gas giants, Jupiter and Saturn, have heavier elements making up between 3 and 13 percent of their mass. Gas giants are thought to consist of an outer layer of molecular hydrogen, surrounding a layer of liquid metallic hydrogen, with a probable molten core with a rocky composition.
It is also important to take losses due to fuel production, transportation, and storage into account. Fuel cell vehicles running on compressed hydrogen may have a power-plant-to-wheel efficiency of 22% if the hydrogen is stored as high-pressure gas, and 17% if it is stored as liquid hydrogen. Fuel cells cannot store energy like a battery, except as hydrogen, but in some applications, such as stand-alone power plants based on discontinuous sources such as solar or wind power, they are combined with electrolyzers and storage systems to form an energy storage system. Most hydrogen is used for oil refining, chemicals and fertilizer production and therefore produced by steam methane reforming, which emits carbon dioxide. The overall efficiency (electricity to hydrogen and back to electricity) of such plants (known as "round-trip efficiency"), using pure hydrogen and pure oxygen can be "from 35 up to 50 percent", depending on gas density and other conditions.. The electrolyzer/fuel cell system can store indefinite quantities of hydrogen, and is therefore suited for long-term storage.
A hydrogen atom attached to a relatively electronegative atom is the hydrogen bond donor.[9] C-H bonds only participate in hydrogen bonding when the carbon atom is bound to electronegative substituents, as is the case in chloroform, CHCl3.[10] In a hydrogen bond, the electronegative atom not covalently attached to the hydrogen is named proton acceptor, whereas the one covalently bound to the hydrogen is named the proton donor. In the donor molecule, the H center is protic. The donor is a Lewis base. Hydrogen bonds are represented as H···Y system, where the dots represent the hydrogen bond. Liquids that display hydrogen bonding (such as water) are called associated liquids.
It may have an exceptionally large core composed of elements heavier than hydrogen and helium: the initial theoretical models gave the core a mass of 70 times Earth's mass; further refinements suggest 80-110 Earth masses. As a result, the planet has been described as a "super-Neptune", in analogy to the core-dominated outer ice giants of our solar system, though whether the core of HD 149026 b is mainly icy or rocky is not currently known. Robert Naeye in "Sky & Telescope" claimed "it contains as much or more heavy elements (elements heavier than hydrogen and helium) than all the planets and asteroids in our solar system combined". In addition to uncertainties of radius, its tidal heating over its history needs be taken into account; if its current orbit is circular and if that had evolved from a more eccentric one, the extra heat increases its expected radius per its model and thereby its core radius.
In February 2017, NASA announced that its Spitzer Space Telescope had revealed seven Earth-size planets in the TRAPPIST-1 system orbiting an ultra-cool dwarf star 40 light-years away from our solar system. Three of these planets are firmly located in the habitable zone, the area around the parent star where a rocky planet is most likely to have liquid water. The discovery sets a new record for greatest number of habitable-zone planets found around a single star outside our solar system. All of these seven planets could have liquid water – the key to life as we know it – under the right atmospheric conditions, but the chances are highest with the three in the habitable zone.
Zinner's PhD research was in high energy physics. He subsequently studied the effects that the environment within our solar system would have on the moon and the parent bodies of meteors, using nuclear particle tracks, micrometeoid craters, and elements in the solar wind. His later research was focused on the information contained in presolar grains carried by early meteorites. These grains were formed in atmospheres and explosions of stars outside of earth's solar system. They can provide information about the history of stellar nucleosynthesis and the formation of the solar system.
The Aerojet Rocketdyne RS-68 (Rocket System 68) is a liquid-fuel rocket engine that uses liquid hydrogen (LH2) and liquid oxygen (LOX) as propellants in a gas-generator power cycle. It is the largest hydrogen-fueled rocket engine ever flown.
The combustion chambers in the SABRE engine are cooled by the oxidant (air/liquid oxygen) rather than by liquid hydrogen to further reduce the system's use of liquid hydrogen compared to stoichiometric systems.
Liquid hydrogen is a common liquid rocket fuel for rocketry applications — both NASA and the United States Air Force operate a large number of liquid hydrogen tanks with an individual capacity up to 3.8 million liters (1 million U.S. gallons). In most rocket engines fueled by liquid hydrogen, it first cools the nozzle and other parts before being mixed with the oxidizer — usually liquid oxygen (LOX) — and burned to produce water with traces of ozone and hydrogen peroxide. Practical H–O rocket engines run fuel-rich so that the exhaust contains some unburned hydrogen. This reduces combustion chamber and nozzle erosion. It also reduces the molecular weight of the exhaust, which can actually increase specific impulse, despite the incomplete combustion.
Liquid hydrogen can be used as the fuel for an internal combustion engine or fuel cell. Various submarines (Type 212 submarine, Type 214 submarine) and concept hydrogen vehicles have been built using this form of hydrogen (see DeepC, BMW H2R). Due to its similarity, builders can sometimes modify and share equipment with systems designed for liquefied natural gas (LNG). However, because of the lower volumetric energy, the hydrogen volumes needed for combustion are large. Unless direct injection is used, a severe gas-displacement effect also hampers maximum breathing and increases pumping losses.
Power to liquid is similar to power to gas, however the hydrogen produced by electrolysis from wind and solar electricity isn't converted into gases such as methane but into liquids such as methanol. Methanol is easier to handle than gases, and requires fewer safety precautions than hydrogen. It can be used for transportation, including aircraft, but also for industrial purposes or in the power sector.
The isotopic homogeneity of our planet and the Solar System provides a blank slate on which to detect the effect of nuclear processes on Earth, in the Solar System, and in objects coming to us from outside the Solar System. Awaiting more here, see natural abundance.
Although traditional definitions of the habitable zone assume that carbon dioxide and water vapor are the most important greenhouse gases (as they are on the Earth),[25] a study[38] led by Ramses Ramirez and co-author Lisa Kaltenegger has shown that the size of the habitable zone is greatly increased if prodigious volcanic outgassing of hydrogen is also included along with the carbon dioxide and water vapor. The outer edge in our solar system would extend out as far as 2.4 AU in that case. Similar increases in the size of the habitable zone were computed for other stellar systems. An earlier study by Ray Pierrehumbert and Eric Gaidos [37] had eliminated the CO2-H2O concept entirely, arguing that young planets could accrete many tens to hundreds of bars of hydrogen from the protoplanetary disc, providing enough of a greenhouse effect to extend the solar system outer edge to 10 AU. In this case, though, the hydrogen is not continuously replenished by volcanism, and is lost within millions to tens-of-millions of years.