Interstellar dust

Only about 0.7 percent of the mass of the interstellar space is within the sort of solid grains, but these grains have a profound effect on the physical conditions within the gas. Their main effect is to soak up stellar radiation; for photons unable to ionize hydrogen and for wavelengths outside absorption lines or bands, the dust grains are far more opaque than the gas. The dust absorption increases with photon energy, so long-wavelength radiation (radio and far-infrared) can penetrate dust freely, near-infrared very well , and ultraviolet relatively poorly. Dark, cold molecular clouds, within which all star formation takes place, owe their existence to dust. Besides absorbing starlight, the dust acts to heat the gas under some conditions (by ejecting electrons produced by the photoelectric effect, following the absorption of a stellar photon) and to chill the gas under other conditions (because the dust can radiate energy more efficiently than the gas then generally is colder). the most important chemical effect of dust is to supply the sole site of molecular hydrogen formation on grain surfaces. It also removes some heavy elements (especially iron and silicon) that might act as coolants to the gas. The optical appearance of most nebulae is significantly modified by the obscuring effects of the dust.

Comments

What is cosmic dust?

What is cosmic dust? The Universe may be a very dusty place. cloud consists of small particles of solid material floating around within the space between the celebs . it's not an equivalent because the dust you discover in your house but more like smoke with small particles varying from collections of just a couple of molecules to grains of 0.1 mm in size. Dust is vital because we discover many it around young stars. actually it helps them to make , and it's also the staple from which planets just like the Earth are formed. The diagram below illustrates the cloud cycle. Dust is made in stars and is then blown off during a slow wind or a huge star explosion. The dust is then ‘recycled’ within the clouds of gas between stars and a few of it's consumed when subsequent generation of stars begins to make . Astronomers wont to consider dust as a nuisance because it absorbs the light from objects, keeping them hidden from our optical telescopes making the Universe app

why interstellar travel happening soon?

The term “moonshot” is usually invoked to denote a project so outrageously ambitious that it can only be described by comparing it to the Apollo 11 mission to land the primary human on the Moon. The Breakthrough Starshot Initiative transcends the moonshot descriptor because its purpose goes far beyond the Moon. The aptly-named project seeks to visit the closest stars. The brainchild of Russian-born tech entrepreneur billionaire Yuri Milner, Breakthrough Starshot was announced in April 2016 at a news conference joined by renowned physicists including Hawking and Freeman Dyson. While still early, the present vision is that thousands of wafer-sized chips attached to large, silver lightsails are going to be placed into Earth orbit and accelerated by the pressure of an intense Earth-based laser hitting the lightsail. After just two minutes of being driven by the laser, the spacecraft are going to be traveling at one-fifth the speed of light—a thousand-fold faster than any macroscopi

How NASA Will Protect Astronauts From Space Radiation at the Moon

How NASA Will Protect Astronauts From Space Radiation at the Moon August 1972, as NASA scientist Ian Richardson remembers it, was hot. In Surrey, England, where he grew up, the fields were brown and dry, and other people tried to remain indoors — out of the Sun, televisions on. except for several days that month, his TV picture kept ending . “Do not adjust your set,” he recalls the BBC announcing. “Heat isn’t causing the interference. It’s sunspots.” The same sunspots that disrupted the tv signals led to enormous solar flares — powerful bursts of energy from the Sun — Aug. 4-7 that year. Between the Apollo 16 and 17 missions, the solar eruptions were a mishap for lunar explorers. Had they been in orbit or on the Moon’s surface, they might have experienced high levels of radiation sparked by the eruptions. Today, the Apollo-era flares function a reminder of the threat of radiation exposure to technology and astronauts in space. Understanding and predicting solar eruptions is cru

Space wonder

Search This Blog