An impact event is a collision between astronomical objects causing measurable effects. Impact events have physical consequences and have been found to occur in planetary systems, though the most frequent involve asteroids, comets or meteoroids and have minimal effect; when large objects impact terrestrial planets such as the Earth, there can be significant physical and biospheric consequences, though atmospheres mitigate many surface impacts through atmospheric entry. Impact craters and structures are dominant landforms on many of the Solar System's solid objects and present the strongest empirical evidence for their frequency and scale. Impact events appear to have played a significant role in the evolution of the Solar System since its formation. Major impact events have shaped Earth's history, have been implicated in the formation of the Earth–Moon system, the evolutionary history of life, the origin of water on Earth and several mass extinctions; the prehistoric Chicxulub impact, 66 million years ago, is believed to be the cause of the Cretaceous–Paleogene extinction event.
Throughout recorded history, hundreds of Earth impacts have been reported, with some occurrences causing deaths, property damage, or other significant localised consequences. One of the best-known recorded events in modern times was the Tunguska event, which occurred in Siberia, Russia, in 1908; the 2013 Chelyabinsk meteor event is the only known such incident in modern times to result in numerous injuries, excluding the 1490 Ch'ing-yang event in China. The Chelyabinsk meteor is the largest recorded object to have encountered the Earth since the Tunguska event; the Comet Shoemaker–Levy 9 impact provided the first direct observation of an extraterrestrial collision of Solar System objects, when the comet broke apart and collided with Jupiter in July 1994. An extrasolar impact was observed in 2013, when a massive terrestrial planet impact was detected around the star ID8 in the star cluster NGC 2547 by NASA's Spitzer space telescope and confirmed by ground observations. Impact events have been a background element in science fiction.
In April 2018, the B612 Foundation reported "It’s 100 per cent certain we’ll be hit, but we’re not 100 per cent certain when." In 2018, physicist Stephen Hawking, in his final book Brief Answers to the Big Questions, considered an asteroid collision to be the biggest threat to the planet. In June 2018, the US National Science and Technology Council warned that America is unprepared for an asteroid impact event, has developed and released the "National Near-Earth Object Preparedness Strategy Action Plan" to better prepare. According to expert testimony in the United States Congress in 2013, NASA would require at least five years of preparation before a mission to intercept an asteroid could be launched. Major impact events have shaped Earth's history, having been implicated in the formation of the Earth–Moon system, the evolutionary history of life, the origin of water on Earth, several mass extinctions. Impact structures are the result of impact events on solid objects and, as the dominant landforms on many of the System's solid objects, present the most solid evidence of prehistoric events.
Notable impact events include the Late Heavy Bombardment, which occurred early in history of the Earth–Moon system, the Chicxulub impact, 66 million years ago, believed to be the cause of the Cretaceous–Paleogene extinction event. Small objects collide with Earth. There is an inverse relationship between the frequency of such events; the lunar cratering record shows that the frequency of impacts decreases as the cube of the resulting crater's diameter, on average proportional to the diameter of the impactor. Asteroids with a 1 km diameter strike Earth every 500,000 years on average. Large collisions – with 5 km objects – happen once every twenty million years; the last known impact of an object of 10 km or more in diameter was at the Cretaceous–Paleogene extinction event 66 million years ago. The energy released by an impactor depends on diameter, density and angle; the diameter of most near-Earth asteroids that have not been studied by radar or infrared can only be estimated within about a factor of two based on the asteroid brightness.
The density is assumed because the diameter and mass are generally estimates. Due to Earth's escape velocity, the minimum impact velocity is 11 km/s with asteroid impacts averaging around 17 km/s on the Earth; the most probable impact angle is 45 degrees. Impact conditions such as asteroid size and speed, but density and impact angle determine the kinetic energy released in an impact event; the more energy is released, the more damage is to occur on the ground due to the environmental effects triggered by the impact. Such effects can be shock waves, heat radiation, the formation of craters with associated earthquakes, tsunamis if water bodies are hit. Human populations are vulnerable to these effects. Large seiche waves arising from earthquakes and large-scale deposit of debris can occur within minutes of impact, thousands of kilometres from impact. Stony asteroids with a diameter of 4 meters enter Earth's atmosphere about once a year. Asteroids with a diameter of 7 meters enter the atmosphere about every 5 years with as much kinetic energy as the atomic bomb dropped on Hiroshima, but the air burst is reduced to just 5 kilotons.
These ordinarily explode in the upper atmosphere and most or all of the solids are vaporized. However, asteroids with a diameter of 20 m, which strike Earth tw
Financial management focuses on ratios and debts. It is useful for portfolio management, distribution of dividend, capital raising and looking after fluctuations in foreign currency and product cycles. Financial managers are the people who will do research and based on the research, decide what sort of capital to obtain in order to fund the company's assets as well as maximizing the value of the firm for all the stockholders, it refers to the efficient and effective management of money in such a manner as to accomplish the objectives of the organization. It is the specialized function directly associated with the top management; the significance of this function is not seen in the'Line' but in the capacity of the'Staff' in overall of a company. It has been defined differently by different experts in the field; the term applies to an organization or company's financial strategy, while personal finance or financial life management refers to an individual's management strategy. It includes how to allocate capital, i.e. capital budgeting.
Not only for long term budgeting, but how to allocate the short term resources like current liabilities. It deals with the dividend policies of the share holders. “Financial management may be defined as that area or set of administrative function in an organization which are related with arrangement of cash and credit so that organization may have the means to carry out its objective as satisfactorily as possible." - by Howard & Opton. Profit maximization happens; this is the main objective of Financial Management. Wealth maximization means maximization of shareholders' wealth, it is an advanced goal compared to profit maximization. Survival of company is an important consideration when the financial manager makes any financial decisions. One incorrect decision may lead company to be bankrupt. Maintaining proper cash flow is a short run objective of financial management, it is necessary for operations to pay the day-to-day expenses e.g. raw material, electricity bills, rent etc. A good cash flow ensures the survival of company.
Minimization on capital cost in financial management can help operations gain more profit. It is vague:- There are several types of profits before interest and taxes, profit before taxes, profit after taxes, cash profit etc Estimating the Requirement of Funds: Businesses make forecast on funds needed in both short run and long run, they can improve the efficiency of funding; the estimation is based on production budget. Determining the Capital Structure: Capital structure is how a firm finances its overall operations and growth by using different sources of funds. Once the requirement of funds has estimated, the financial manager should decide the mix of debt and equity and types of debt. Investment Fund: A good investment plan can bring businesses huge returns. To ascertain maximum profit as well as maintain the core value of the organization For new enterprises, it is important to make a good estimation on costs, sales. Consideration on appropriate length sources of finances can help businesses avoid the cash flow problems the failure of setting up.
There are fixed and current sides of assets balance sheet. Fixed assets refers to assets that cannot be converted into cash like plant, equipment etc. A current asset is an item on an entity's balance sheet, either cash, a cash equivalent, or which can be converted into cash within one year, it is not easy for start ups to forecast the current asset, because there are changes in receivables and payables. Investment management related to financial management, is the professional asset management of various securities Managerial finance, a branch of finance concerned with the managerial significance of financial techniques. Corporate finance, a branch of finance concerned with monetary resource allocations made by corporations Financial management for IT services, financial management of IT assets and resources Financial Planning Association, an organization for finance and economics students and professionals Financial Management Service, a bureau of the U. S. Treasury which provides financial services for the government Financial planner, or personal financial planner, is a professional who prepares financial plans for people
Cosmic Variance is a collaborative weblog discussing physics and other topics, written by JoAnne Hewett, Mark Trodden, Sean Carroll, Risa Wechsler, Julianne Dalcanton, John Conway, Daniel Holz. It is the successor to Carroll's earlier blog Preposterous Universe, which began in early 2004 and ran through much of 2005; the blog's name comes from the cosmology concept of cosmic variance. Cosmic Variance has become "undoubtedly the most popular blog written by physicists." In 2006, Nature reported that it was the fourth most popular science blog and one of only five blogs by scientists in the 3500 most popular blogs. As of July 26, 2007, Cosmic Variance had a Technorati authority of 1001 and rank of 2277. In 2008, the blog became part of the Discover magazine website. Most writing on Cosmic Variance focuses on modern physics and cosmology, at a level accessible to the interested non-scientist. However, topics of discussion have ranged including science and religion, science journalism, higher education, politics.
Several discussions on Cosmic Variance have gained attention in the print media, including a discussion on women in science that compared physicist Lisa Randall to Jodie Foster and a post by John Conway about his discovery of a "bump" in particle accelerator data that turned out not to be caused by the Higgs boson. When the engagement of Carroll to science writer Jennifer Ouellette was first announced on his blog, the story was picked up by both the New York Times and the prominent scientific journal Nature. Cosmic Variance has hosted a number of guest bloggers, including string theorist Joseph Polchinski reviewing Lee Smolin's book The Trouble With Physics. Cosmic Variance Blog review at PhysicsWeb