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There are seven meanings listed in OED's entry for the noun hypothesis , two of which are labelled obsolete. See ‘Meaning & use’ for definitions, usage, and quotation evidence.
OED is undergoing a continuous programme of revision to modernize and improve definitions. This entry has not yet been fully revised.
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British english, u.s. english, where does the noun hypothesis come from.
Earliest known use
The earliest known use of the noun hypothesis is in the late 1500s.
OED's earliest evidence for hypothesis is from 1596, in the writing of Earl of Essex.
hypothesis is a borrowing from Greek.
Etymons: Greek ὑπόθεσις .
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Pronunciation, compounds & derived words, entry history for hypothesis, n..
hypothesis, n. was first published in 1899; not yet revised.
hypothesis, n. was last modified in July 2023.
Revision of the OED is a long-term project. Entries in oed.com which have not been revised may include:
Revisions and additions of this kind were last incorporated into hypothesis, n. in July 2023.
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June 24, 2024
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by University of Warsaw
The gravitational wave detectors LIGO and Virgo have detected a population of massive black holes whose origin is one of the biggest mysteries in modern astronomy. According to one hypothesis, these objects may have formed in the very early universe and may include dark matter, a mysterious substance filling the universe.
A team of scientists from the OGLE (Optical Gravitational Lensing Experiment) survey from the Astronomical Observatory of the University of Warsaw have announced the results of nearly 20-year-long observations indicating that such massive black holes may comprise at most a few percent of dark matter . Another explanation, therefore, is needed for gravitational wave sources. The results of the research were published in a study in Nature and a study in The Astrophysical Journal Supplement Series .
Various astronomical observations indicate that ordinary matter, which we can see or touch, comprises only 5% of the total mass and energy budget of the universe. In the Milky Way, for every 1 kg of ordinary matter in stars, there is 15 kg of dark matter, which does not emit any light and interacts only by means of its gravitational pull.
"The nature of dark matter remains a mystery. Most scientists think it is composed of unknown elementary particles," says Dr. Przemek Mr.óz from the Astronomical Observatory, University of Warsaw, the lead author of both articles. "Unfortunately, despite decades of efforts, no experiment (including experiments carried out with the Large Hadron Collider) has found new particles that could be responsible for dark matter."
Since the first detection of gravitational waves from a merging pair of black holes in 2015, the LIGO and Virgo experiments have detected more than 90 such events. Astronomers noticed that black holes detected by LIGO and Virgo are typically significantly more massive (20–100 solar masses) than those known previously in the Milky Way (5–20 solar masses).
"Explaining why these two populations of black holes are so different is one of the biggest mysteries of modern astronomy," says Dr. Mr.óz.
One possible explanation postulates that LIGO and Virgo detectors have uncovered a population of primordial black holes that may have formed in the very early universe. Their existence was first proposed over 50 years ago by British theoretical physicist Stephen Hawking, and independently, by the Soviet physicist Yakov Zeldovich.
"We know that the early universe was not ideally homogeneous—small density fluctuations gave rise to current galaxies and galaxy clusters," says Dr. Mr.óz. "Similar density fluctuations, if they exceed a critical density contrast, may collapse and form black holes."
Since the first detection of gravitational waves, more and more scientists have been speculating that such primordial black holes may comprise a significant fraction, if not all, of dark matter.
Fortunately, this hypothesis can be verified with astronomical observations. We observe that copious amounts of dark matter exist in the Milky Way. If it were composed of black holes, we should be able to detect them in our cosmic neighborhood. Is this possible, given that black holes do not emit any detectable light?
According to Einstein's theory of general relativity, light may be bent and deflected in the gravitational field of massive objects, a phenomenon called gravitational microlensing .
"Microlensing occurs when three objects—an observer on Earth, a source of light, and a lens—virtually ideally align in space," says Prof. Andrzej Udalski, the principal investigator of the OGLE survey. "During a microlensing event, the source's light may be deflected and magnified, and we observe a temporary brightening of the source's light."
The duration of the brightening depends on the mass of the lensing object: the higher the mass, the longer the event. Microlensing events by solar mass objects typically last several weeks, whereas those by black holes that are 100 times more massive than the sun would last a few years.
The idea of using gravitational microlensing to study dark matter is not new. It was first proposed in the 1980s by Polish astrophysicist Bohdan Paczyński. His idea inspired the start of three major experiments: Polish OGLE, American MACHO, and French EROS. The first results from these experiments demonstrated that black holes less massive than one solar mass may comprise less than 10% of dark matter. These observations were not, however, sensitive to extremely long-timescale microlensing events, and therefore, not sensitive to massive black holes, similar to those recently detected with gravitational-wave detectors.
In the new article in The Astrophysical Journal Supplement Series , OGLE astronomers present the results of nearly 20-year-long photometric monitoring of almost 80 million stars located in a nearby galaxy, called the Large Magellanic Cloud, and the searches for gravitational microlensing events. The analyzed data was collected during the third and fourth phases of the OGLE project from 2001 to 2020.
"This data set provides the longest, largest, and most accurate photometric observations of stars in the Large Magellanic Cloud in the history of modern astronomy," says Prof. Udalski.
The second article, published in Nature , discusses the astrophysical consequences of the findings.
"If the entire dark matter in the Milky Way was composed of black holes of 10 solar masses, we should have detected 258 microlensing events," says Dr. Mr.óz. "For 100 solar mass black holes, we expected 99 microlensing events. For 1,000 solar mass black holes—27 microlensing events."
In contrast, the OGLE astronomers have found only 13 microlensing events. Their detailed analysis demonstrates that all of them can be explained by the known stellar populations in the Milky Way or the Large Magellanic Cloud itself, not by black holes.
"That indicates that massive black holes can compose at most a few percent of dark matter," says Dr. Mr.óz.
The detailed calculations demonstrate that black holes of 10 solar masses may comprise at most 1.2% of dark matter, 100 solar mass black holes—3.0% of dark matter, and 1,000 solar mass black holes—11% of dark matter.
"Our observations indicate that primordial black holes cannot comprise a significant fraction of the dark matter, and simultaneously, explain the observed black hole merger rates measured by LIGO and Virgo," says Prof. Udalski.
Therefore, other explanations are needed for massive black holes detected by LIGO and Virgo. According to one hypothesis, they formed as a product of the evolution of massive, low-metallicity stars. Another possibility involves mergers of less massive objects in dense stellar environments, such as globular clusters.
"Our results will remain in astronomy textbooks for decades to come," adds Prof. Udalski.
Przemek Mróz et al, Microlensing Optical Depth and Event Rate toward the Large Magellanic Cloud Based on 20 yr of OGLE Observations, The Astrophysical Journal Supplement Series (2024). DOI: 10.3847/1538-4365/ad452e
Journal information: arXiv , Nature
Provided by University of Warsaw
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COMMENTS
hypothesis: [noun] an assumption or concession made for the sake of argument. an interpretation of a practical situation or condition taken as the ground for action.
A hypothesis is a tentative statement about the relationship between two or more variables. It is a specific, testable prediction about what you expect to happen in a study. It is a preliminary answer to your question that helps guide the research process. Consider a study designed to examine the relationship between sleep deprivation and test ...
HYPOTHESIS definition: 1. an idea or explanation for something that is based on known facts but has not yet been proved…. Learn more.
HYPOTHESIS meaning: 1. an idea or explanation for something that is based on known facts but has not yet been proved…. Learn more.
Developing a hypothesis (with example) Step 1. Ask a question. Writing a hypothesis begins with a research question that you want to answer. The question should be focused, specific, and researchable within the constraints of your project. Example: Research question.
Hypothesis definition: a proposition, or set of propositions, set forth as an explanation for the occurrence of some specified group of phenomena, either asserted merely as a provisional conjecture to guide investigation (working hypothesis ) or accepted as highly probable in the light of established facts.. See examples of HYPOTHESIS used in a sentence.
Definition: Hypothesis is an educated guess or proposed explanation for a phenomenon, based on some initial observations or data. It is a tentative statement that can be tested and potentially proven or disproven through further investigation and experimentation. Hypothesis is often used in scientific research to guide the design of experiments ...
The hypothesis of Andreas Cellarius, showing the planetary motions in eccentric and epicyclical orbits. A hypothesis (pl.: hypotheses) is a proposed explanation for a phenomenon.For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous observations that cannot satisfactorily be explained with ...
hypothesis, something supposed or taken for granted, with the object of following out its consequences (Greek hypothesis, "a putting under," the Latin equivalent being suppositio ). Discussion with Kara Rogers of how the scientific model is used to test a hypothesis or represent a theory. Kara Rogers, senior biomedical sciences editor of ...
hypothesis: 1 n a tentative insight into the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena "a scientific hypothesis that survives experimental testing becomes a scientific theory" Synonyms: possibility , theory Types: show 17 types... hide 17 types... hypothetical a hypothetical ...
3 meanings: 1. a suggested explanation for a group of facts or phenomena, either accepted as a basis for further verification.... Click for more definitions.
A hypothesis (plural hypotheses) is a proposed explanation for an observation. The definition depends on the subject. In science, a hypothesis is part of the scientific method. It is a prediction or explanation that is tested by an experiment. Observations and experiments may disprove a scientific hypothesis, but can never entirely prove one.
The hypothesis is one of the early steps in the entire scientific process. Scientists form a hypothesis after asking a question and conducting their initial research. Once they made a hypothesis, scientists can then conduct their research or experiment, analyze the results and assess the validity of their hypothesis statement. Learn about what ...
A research hypothesis (also called a scientific hypothesis) is a statement about the expected outcome of a study (for example, a dissertation or thesis). To constitute a quality hypothesis, the statement needs to have three attributes - specificity, clarity and testability. Let's take a look at these more closely.
A hypothesis is a prediction of what will be found at the outcome of a research project and is typically focused on the relationship between two different variables studied in the research. It is usually based on both theoretical expectations about how things work and already existing scientific evidence. Within social science, a hypothesis can ...
It seeks to explore and understand a particular aspect of the research subject. In contrast, a research hypothesis is a specific statement or prediction that suggests an expected relationship between variables. It is formulated based on existing knowledge or theories and guides the research design and data analysis. 7.
Hypothesis Meaning. A hypothesis is a proposed statement that is testable and is given for something that happens or observed. It is made using what we already know and have seen, and it's the basis for scientific research. A clear guess tells us what we think will happen in an experiment or study.
Simple hypothesis. A simple hypothesis is a statement made to reflect the relation between exactly two variables. One independent and one dependent. Consider the example, "Smoking is a prominent cause of lung cancer." The dependent variable, lung cancer, is dependent on the independent variable, smoking. 4.
If the hypothesis is a relational hypothesis, then it should be stating the relationship between variables. The hypothesis must be specific and should have scope for conducting more tests. The way of explanation of the hypothesis must be very simple and it should also be understood that the simplicity of the hypothesis is not related to its ...
A hypothesis is an assumption made before any research has been done. It is formed so that it can be tested to see if it might be true. A theory is a principle formed to explain the things already shown in data. Because of the rigors of experiment and control, it is much more likely that a theory will be true than a hypothesis.
Hypothesis is a prediction of the outcome of a study. Hypotheses are drawn from theories and research questions or from direct observations. In fact, a research problem can be formulated as a hypothesis. To test the hypothesis we need to formulate it in terms that can actually be analysed with statistical tools.
The earliest known use of the noun hypothesis is in the late 1500s. OED's earliest evidence for hypothesis is from 1596, in the writing of Earl of Essex. hypothesis is a borrowing from Greek. Etymons: Greek ὑπόθεσις. See etymology.
The gravitational wave detectors LIGO and Virgo have detected a population of massive black holes whose origin is one of the biggest mysteries in modern astronomy. According to one hypothesis ...